Replace multiple add_basic_rule() calls with per-item-proxy-class add_*_rules().

Rename extension cauldrons to pattern cauldron_*.lua

CONTRIBUTING.md

@@ -32,6 +32,8 @@ playerbase on low spec computers, optimizations are hard to investigate.
 * [Matrix](https://app.element.io/#/room/#mc2:matrix.org)
 * [Reddit](https://www.reddit.com/r/MineClone2/)
 * [Minetest forums](https://forum.minetest.net/viewtopic.php?f=50&t=16407)
+* [ContentDB](https://content.minetest.net/packages/wuzzy/mineclone2/)
+* [OpenCollective](https://opencollective.com/mineclone2)
 
 ## Using git
 MineClone2 is developed using the version control system
@@ -194,9 +196,16 @@ MeseHub, let us know what you think about a topic and help us make
 decisions. Also, note that a lot of discussion takes place on the
 Discord server, so it's definitely worth checking it out.
 
+### Funding
+You can help pay for our infrastructure (Mesehub) by donating to our
+OpenCollective link (See Links section).
+
 ### Crediting
 If you opened or have contributed to an issue, you receive the
 `Community` role on our Discord (after asking for it).
+OpenCollective Funders are credited in their own section in
+`CREDITS.md` and receive a special role "Funder" on our discord (unless
+they have made their donation Incognito).
 
 ## How you can help as a programmer
 (Almost) all the MineClone2 development is done using pull requests.

CREDITS.md

@@ -130,6 +130,9 @@
 * todoporlalibertad
 * Marcin Serwin
 
+## Funders
+* 40W
+
 ## Special thanks
 * celeron55 for creating Minetest
 * Jordach for the jukebox music compilation from Big Freaking Dig

README.md

@@ -85,6 +85,8 @@ The MineClone2 repository is hosted at Mesehub. To contribute or report issues,
 * Matrix: <https://app.element.io/#/room/#mc2:matrix.org>
 * Reddit: <https://www.reddit.com/r/MineClone2/>
 * Minetest forums: <https://forum.minetest.net/viewtopic.php?f=50&t=16407>
+* ContentDB: <https://content.minetest.net/packages/wuzzy/mineclone2/>
+* OpenCollective: <https://opencollective.com/mineclone2>
 
 ## Target
 - Crucially, create a stable, moddable, free/libre clone of Minecraft

mods/CORE/mcl_util/init.lua

@@ -1,5 +1,27 @@
 mcl_util = {}
 
+-- Updates all values in t using values from to*.
+function table.update(t, ...)
+	for _, to in ipairs{...} do
+		for k,v in pairs(to) do
+			t[k] = v
+		end
+	end
+	return t
+end
+
+-- Updates nil values in t using values from to*.
+function table.update_nil(t, ...)
+	for _, to in ipairs{...} do
+		for k,v in pairs(to) do
+			if t[k] == nil then
+				t[k] = v
+			end
+		end
+	end
+	return t
+end
+
 -- Based on minetest.rotate_and_place
 
 --[[

mods/CORE/mcl_worlds/API.md

@@ -12,7 +12,7 @@ Params:
 
 * pos: position
 
-## mcl_worlds.y_to_layer(y)
+## mcl_worlds.y_to_layer(y)
 This function is used to calculate the minetest y layer and dimension of the given <y> minecraft layer.
 Mainly used for ore generation.
 Takes an Y coordinate as input and returns:

mods/ENTITIES/mcl_boats/init.lua

@@ -115,7 +115,7 @@ local boat = {
 	collisionbox = {-0.5, -0.35, -0.5, 0.5, 0.3, 0.5},
 	visual = "mesh",
 	mesh = "mcl_boats_boat.b3d",
-	textures = {"mcl_boats_texture_oak_boat.png"},
+	textures = {"mcl_boats_texture_oak_boat.png", "mcl_boats_texture_oak_boat.png", "mcl_boats_texture_oak_boat.png", "mcl_boats_texture_oak_boat.png", "mcl_boats_texture_oak_boat.png"},
 	visual_size = boat_visual_size,
 	hp_max = boat_max_hp,
 	damage_texture_modifier = "^[colorize:white:0",
@@ -148,6 +148,11 @@ function boat.on_activate(self, staticdata, dtime_s)
 		self._v = data.v
 		self._last_v = self._v
 		self._itemstring = data.itemstring
+
+		while #data.textures < 5 do
+			table.insert(data.textures, data.textures[1])
+		end
+
 		self.object:set_properties({textures = data.textures})
 	end
 end
@@ -434,8 +439,9 @@ for b=1, #boat_ids do
 				pos = vector.add(pos, vector.multiply(dir, boat_y_offset_ground))
 			end
 			local boat = minetest.add_entity(pos, "mcl_boats:boat")
+			local texture = "mcl_boats_texture_"..images[b].."_boat.png"
 			boat:get_luaentity()._itemstring = itemstring
-			boat:set_properties({textures = { "mcl_boats_texture_"..images[b].."_boat.png" }})
+			boat:set_properties({textures = { texture, texture, texture, texture, texture }})
 			boat:set_yaw(placer:get_look_horizontal())
 			if not minetest.is_creative_enabled(placer:get_player_name()) then
 				itemstack:take_item()

mods/ENVIRONMENT/mcl_weather/rain.lua

@@ -228,22 +228,20 @@ if mcl_weather.allow_abm then
 	-- Slowly fill up cauldrons
 	minetest.register_abm({
 		label = "Rain fills cauldrons with water",
-		nodenames = {"mcl_cauldrons:cauldron", "mcl_cauldrons:cauldron_1", "mcl_cauldrons:cauldron_2"},
+		nodenames = {"group:cauldron"},
 		interval = 56.0,
 		chance = 1,
 		action = function(pos, node, active_object_count, active_object_count_wider)
 			-- Rain is equivalent to a water bottle
 			if mcl_weather.rain.raining and mcl_weather.is_outdoor(pos) then
-				if node.name == "mcl_cauldrons:cauldron" then
-					minetest.set_node(pos, {name="mcl_cauldrons:cauldron_1"})
-				elseif node.name == "mcl_cauldrons:cauldron_1" then
-					minetest.set_node(pos, {name="mcl_cauldrons:cauldron_2"})
-				elseif node.name == "mcl_cauldrons:cauldron_2" then
-					minetest.set_node(pos, {name="mcl_cauldrons:cauldron_3"})
-				elseif node.name == "mcl_cauldrons:cauldron_1r" then
-					minetest.set_node(pos, {name="mcl_cauldrons:cauldron_2r"})
-				elseif node.name == "mcl_cauldrons:cauldron_2r" then
-					minetest.set_node(pos, {name="mcl_cauldrons:cauldron_3r"})
+				local newnode
+				if mcl_cauldrons.is_cauldron(node) then
+					if mcl_cauldrons.is_empty(node) or mcl_cauldrons.has_substance(node, "cauldron_water") then
+						newnode = mcl_cauldrons.fill_levels(node, 1, "cauldron_water")
+					end
+				end
+				if newnode then
+					minetest.set_node(pos, newnode)
 				end
 			end
 		end

mods/HUD/mcl_credits/people.lua

@@ -132,6 +132,9 @@ return {
 		"todoporlalibertad",
 		"Marcin Serwin",
 	}},
+	{S("Funders"), 0xF7FF00, {
+		"40W",
+	}},
 	{S("Special thanks"), 0x00E9FF, {
 		"celeron55 for creating Minetest",
 		"Jordach for the jukebox music compilation from Big Freaking Dig",

mods/ITEMS/mcl_banners/init.lua

@@ -348,6 +348,23 @@ minetest.register_node("mcl_banners:hanging_banner", {
 	end,
 })
 
+local function wash_banner(itemstack)
+	local imeta = itemstack:get_meta()
+	local layers_raw = imeta:get_string("layers")
+	local layers = minetest.deserialize(layers_raw)
+	if type(layers) == "table" and #layers > 0 then
+		table.remove(layers)
+		imeta:set_string("layers", minetest.serialize(layers))
+		local newdesc = mcl_banners.make_advanced_banner_description(itemstack:get_definition().description, layers)
+		local mname = imeta:get_string("name")
+		-- Don't change description if item has a name
+		if mname == "" then
+			imeta:set_string("description", newdesc)
+		end
+		return itemstack
+	end
+end
+
 -- for pattern_name, pattern in pairs(patterns) do
 for colorid, colortab in pairs(mcl_banners.colors) do
     for i, pattern_name in ipairs(pattern_names) do
@@ -425,6 +442,10 @@ for colorid, colortab in pairs(mcl_banners.colors) do
 		groups = groups,
 		stack_max = 16,
 
+		_mcl_on_wash = function(itemstack)
+			return wash_banner(itemstack)
+		end,
+
 		on_place = function(itemstack, placer, pointed_thing)
 			local above = pointed_thing.above
 			local under = pointed_thing.under

mods/ITEMS/mcl_cauldrons/API.md

@@ -0,0 +1,88 @@
+# `mcl_cauldrons`
+
+This mod add an API to add cauldrons to mcl.
+
+
+Node definitions
+----------------
+
+Extensions to the base node definitions (as passed to `minetest.register_node()`) for cauldrons:
+
+* `.groups.cauldron`: 1 - is a cauldron
+* `.groups.cauldron_filled`: number 0..3 - content level (0=empty, 3=full)
+* `.groups.cauldron_maximum`: number 1.. - maximum contents level
+* `._mcl_cauldron_substance`: string - content of cauldron (nil for empty)
+
+
+### `mcl_cauldrons.registered_cauldrons`
+Table containing cauldron definitions, indexed by name.
+
+### `mcl_cauldrons.register_cauldron_node(nodename, cauldron_def)`
+
+
+Cauldron interactions
+---------------------
+
+### `mcl_cauldrons.find_cauldron(substance, fill_level)`
+Returns table, { node\_name, node\_definition }, returns nil if no match.
+Find registered cauldron best matching substance and fill level.
+* `substance`: string, one of the groups keys qualifying the content (e.g. `"cauldron_water"`); empty string for empty cauldron.
+* `fill_level`: desired fill level of cauldron; `nil` for first/any match; 0 resolves to empty cauldron.
+
+### `mcl_cauldrons.is_cauldron(node)`
+Returns boolean.
+Test is nodename describes a cauldron.
+* `node`: Minetest node { name, param1, param2 }
+
+### `mcl_cauldrons.is_empty(node)`
+Returns boolean.
+Test cauldron is empty.
+* `node`: Minetest node { name, param1, param2 }
+
+### `mcl_cauldrons.is_full(node)`
+Returns boolean.
+Test cauldron is full.
+* `node`: Minetest node { name, param1, param2 }
+
+### `mcl_cauldrons.has_substance(node, substance)`
+Returns boolean.
+Test the content is a certain substance.
+* `node`: Minetest node { name, param1, param2 }
+* `substance`: string, one of the groups key qualifying the content (e.g. `"cauldron_water"`).
+
+### `mcl_cauldrons.get_maximum(node, substance)`
+Returns number.
+Get the maximum number of levels for requested substance.
+* `node`: Minetest node { name, param1, param2 }
+* `substance`: string, group-key qualifying the content (e.g. `"cauldron_water"`); `nil` for any/do-not-care.
+
+### `mcl_cauldrons.get_level(node, substance)`
+Returns number.
+Get the fill level of the requested substance.
+* `node`: Minetest node { name, param1, param2 }
+* `substance`: string, group-key qualifying the content (e.g. `"cauldron_water"`); `nil` for any/do-not-care.
+
+### `mcl_cauldrons.set_level(node, fill_level, substance)`
+Returns node { name, param1, param2 }.
+Set the fill level of cauldron, with optional explicit substance.
+* `node`: Minetest node { name, param1, param2 }
+* `substance`: string, group-key of cauldron content; `nil` to preserve substance.
+
+### `mcl_cauldrons.fill_levels(node, change_levels, substance)`
+Returns node { name, param1, param2 }.
+Increase levels in cauldron, constrained by game rules.
+* `node`: Minetest node { name, param1, param2 }
+* `substance`: string, group-key of cauldron content; `nil` to preserve substance.
+
+### `mcl_cauldrons.drain_levels(nodename, change_levels, substance)`
+Returns node { name, param1, param2 }.
+Reduce levels in cauldron, constrained by game rules.
+* `node`: Minetest node { name, param1, param2 }
+* `substance`: string, group-key of cauldron content; `nil` to preserve substance.
+
+### `mcl_cauldrons.register_cauldron_node(nodename, cauldron_definition, doc_alias)`
+Register cauldron's node defintion.  Affects `mcl_cauldrons.registered_cauldrons` while ultimately ending up at `minetest.register_node`.
+* `nodename`: string - name to assign to registered node.
+* `cauldron_defintion`: table - node definition (expecting mcl\_cauldrons extensions).
+* `doc_alias`: string - documentation (in-game encyclopedia) entry associated with this definition.
+

mods/ITEMS/mcl_cauldrons/api.lua

@@ -0,0 +1,354 @@
+--- API for Cauldrons in MineClone2.
+
+-- Documentation Generator is LDoc (backwards-compatible with LuaDoc)
+-- $ ldoc -f markdown ...
+
+--- Table of registered cauldron nodes, indexed by name.
+-- Filled by register_cauldron_node().
+mcl_cauldrons.registered_cauldrons = {}
+--- List of recognized substances in cauldron.
+-- Filled by register_cauldron_node()
+-- @see mcl_cauldrons.list_substances
+mcl_cauldrons.substances = {}
+
+
+--- Provided for documentation purposes, frequently-used table format.
+--
+-- Position in world { x, y, z }
+-- @name Position
+-- @class table
+local Position = { x=nil, y=nil, z=nil }
+
+--- Provided for documentation purposes, frequently-used table format.
+--
+-- Node description { name, param1, param2 }, as used by `minetest.get_node()` and `minetest.set_node()`
+-- (not to be confused with node definition)
+-- @name Node
+-- @class table
+local Node = { name=nil, param1=nil, param2=nil }
+
+-- symbolic constants.
+
+--- Levels of cauldron change per bucket.
+mcl_cauldrons.BUCKET_FILL_LEVELS = 3
+--- Levels of cauldron change per bottle (potion).
+mcl_cauldrons.BOTTLE_FILL_LEVELS = 1
+
+
+--- Determine registered cauldron satisfying specifications.
+--
+-- Cauldrons are described by two state variables: { substance, fill\_level }.
+--
+-- Determine the cauldron node definition from these states.
+--
+-- e.g. `make_cauldron("water", 2)` -> `"mcl_cauldrons:cauldron_water_2"`
+--
+-- @param substance string : Desired cauldron substance, nil for any substance.
+-- @param fill_level number : Desired cauldron fill level, nil to match any.
+-- @return 2-value: cauldron node name (string), cauldron node definition (table)
+function mcl_cauldrons.make_cauldron(substance, fill_level)
+	local empty_nodename = "mcl_cauldrons:cauldron"
+	local empty_nodedef = mcl_cauldrons.registered_cauldrons[empty_nodename]
+	if (substance == "") then
+		return empty_nodename, empty_nodedef
+	end
+	for nodename, nodedef in pairs(mcl_cauldrons.registered_cauldrons) do
+		-- matched on substance: 'any', or exact match from .groups.
+		local match_substance = (substance == nil) or (nodedef._mcl_cauldron_substance == substance)
+		-- matched on fill_level: 'any', or exact match from .groups.
+		local match_level = (fill_level == nil) or (nodedef.groups.cauldron_filled == fill_level)
+		if match_substance and match_level then
+			return nodename, nodedef
+		end
+	end
+	-- no match, use empty.
+	return empty_nodename, empty_nodedef
+end
+
+--- Test: node describes a cauldron
+--
+-- @param node Node : Cauldron node description (as from minetest.get_node())
+-- @return boolean: node is a cauldron
+function mcl_cauldrons.node_is_cauldron(node)
+	if node == nil then return false end
+	return (minetest.get_item_group(node.name, "cauldron") ~= 0)
+end
+
+--- Test: position holds a cauldron
+--
+-- @param pos Position : World position (as passed to minetest.get_node())
+-- @return boolean: a cauldron is at position
+function mcl_cauldrons.is_cauldron(pos)
+	local node = minetest.get_node(pos)
+	return mcl_cauldrons.node_is_cauldron(node)
+end
+
+--- Test: cauldron node contains specified substance
+--
+-- @param node Node : Cauldron node description
+-- @param substance string : substance that should be present in cauldron.
+-- @return boolean
+function mcl_cauldrons.node_has_substance(node, substance)
+	--return (minetest.get_item_group(node.name, substance) ~= 0)
+	local nodedef = minetest.registered_nodes[node.name]
+	return (nodedef._mcl_cauldron_substance == substance)
+end
+
+--- Test: cauldron at position contains specified substance
+--
+-- @param pos Position : World position
+-- @param substance string : substance that should be present in cauldron
+-- @return boolean
+function mcl_cauldrons.has_substance(pos, substance)
+	local node = minetest.get_node(pos)
+	return mcl_cauldrons.node_has_substance(node)
+end
+
+--- List of supported substances
+--
+-- @return table: List of substances
+function mcl_cauldrons.list_substances()
+	return mcl_cauldrons.substances
+end
+
+--- Get substance inside cauldron node
+--
+-- @param node Node : Cauldron node description
+-- @return string : Substance inside cauldron
+-- @return `nil`: Cauldron is empty
+function mcl_cauldrons.node_get_substance(node)
+	local nodedef = mcl_cauldrons.registered_cauldrons[node.name]
+	return nodedef._mcl_cauldron_substance
+end
+
+--- Get substance inside cauldron (by position)
+--
+-- @param pos Position : World position
+-- @return string: Substance inside cauldron
+-- @return `nil`: Cauldron is empty
+function mcl_cauldrons.get_substance(pos)
+	local node = minetest.get_node(pos)
+	return mcl_cauldrons.node_get_substance(node)
+end
+
+--- Get maximum number of levels available for cauldron node -> number
+function mcl_cauldrons.node_get_maximum(node)
+	local nodename = node.name
+	return minetest.get_item_group(nodename, "cauldron_maximum")
+end
+
+function mcl_cauldrons.get_maximum(pos)
+	local node = minetest.get_node(pos)
+	return mcl_cauldrons.node_get_maximum(node)
+end
+
+--- Get current level from cauldron node
+--
+-- @param node Node : Cauldron node description
+-- @return number: Typically one of 0,1,2,3
+function mcl_cauldrons.node_get_level(node)
+	return minetest.get_item_group(node.name, "cauldron_filled")
+end
+
+--- Get current level of cauldron (by position)
+--
+-- @param pos Position : World position
+-- @return number: Typically one of 0,1,2,3
+-- Get current level of cauldron -> number
+function mcl_cauldrons.get_level(pos)
+	local node = minetest.get_node(pos)
+	return mcl_cauldrons.node_get_level(node)
+end
+
+--- Test: cauldron node is empty
+--
+-- @param node Node : Cauldron node description
+-- @return boolean
+function mcl_cauldrons.node_is_empty(node)
+	if not mcl_cauldrons.node_is_cauldron(node) then
+		error("not a cauldron", node.name)
+	end
+	if minetest.get_item_group(node.name, "cauldron_filled") == 0 then
+		return true
+	end
+	return false
+end
+
+--- Test: cauldron is empty (by position)
+--
+-- @param pos Position : World position
+-- @return boolean
+function mcl_cauldrons.is_empty(pos)
+	local node = minetest.get_node(pos)
+	return mcl_cauldrons.node_is_empty(node)
+end
+
+--- Test: cauldron node is full
+--
+-- @param node Node : Cauldron node description
+-- @return boolean
+function mcl_cauldrons.node_is_full(node)
+	local maximum = mcl_cauldrons.get_maximum(node)
+	local current = mcl_cauldrons.get_level(node)
+	return (current >= maximum)
+end
+
+--- Test: cauldron is full (by position)
+--
+-- @param pos Position : World position
+-- @return boolean
+function mcl_cauldrons.is_full(pos)
+	local node = minetest.get_node(pos)
+	return mcl_cauldrons.node_is_full(node)
+end
+
+--- Convert cauldron node to satisfy content specifications.
+--
+-- Cauldron specification is subject to normalization based on substance
+-- and fill level (e.g. any substance at level 0 becomes empty cauldron).
+--
+-- @param node Node : node to have its contents changed
+-- @param substance string : intended cauldron substance
+-- @param fill_level number : intended fill level
+-- @return table: new cauldron node
+function mcl_cauldrons.node_set_content(node, substance, fill_level)
+	local newname = mcl_cauldrons.make_cauldron(substance, fill_level)
+	local newnode = table.copy(node)
+	newnode.name = newname
+	return newnode
+end
+
+--- Place cauldron of specified substance and fill level at world position.
+--
+-- Cauldron specification is subject to normalization based on substance
+-- and fill level (e.g. any substance at level 0 becomes empty cauldron).
+--
+-- @param pos Position : World position.
+-- @param substance : string cauldron substance (item def _mcl_cauldron_substance)
+-- @param fill_level number : cauldron fill level (typically 0,1,2,3)
+-- @return table: new cauldron node (as passed to minetest.set_pos())
+function mcl_cauldrons.set_content(pos, substance, fill_level)
+	local node = minetest.get_node(pos)
+	if not mcl_cauldrons.is_cauldron(node) then return end
+	local newnode = mcl_cauldrons.node_set_content(node, substance, fill_level)
+	minetest.set_node(pos, newnode)
+	return newnode
+end
+
+
+--- Wrapper to register cauldron-specific nodes.
+-- additional bookkeeping specific to mcl_cauldrons.
+-- @param nodename string : name of node
+-- @param nodedef table : node description
+-- @param doc_alias string : for documentation purposes, alias for this specified node name.
+function mcl_cauldrons.register_cauldron_node(nodename, nodedef, doc_alias)
+	mcl_cauldrons.registered_cauldrons[nodename] = nodedef
+	minetest.register_node(nodename, nodedef)
+	if doc_alias and has_doc then
+		doc.add_entry_alias("nodes", doc_alias, "nodes", nodename)
+	end
+	-- build list of supported substances.
+	if table.indexof(mcl_cauldrons.substances, nodedef._mcl_cauldron_substance) == -1 then
+		table.insert(mcl_cauldrons.substances, nodedef._mcl_cauldron_substance)
+	end
+end
+
+
+--- List of item proxy classes.
+--
+-- For item interactions (right-click), handlers for items that may interact
+-- with cauldron.
+mcl_cauldrons.item_proxies = {}
+
+--- Add item proxy class.
+--
+-- ItemProxy classes expose `do_apply()` that carries out the duties of
+-- `on_rightclick()` (applying itemstack to cauldron node).  This method
+-- returns 2 values, a boolean and an ItemStack.
+-- The first value is true if no further handling is required (typically
+-- interaction is complete), false if it could not handle the interaction.
+-- Priority of proxy classes are determined by lateness in `add_item_proxy` --
+-- later additions take priority over earlier ones, allowing for stacked mods
+-- to override basal behavior.
+--
+-- @param proxy ItemProxy : ItemProxy prototype (to have do_apply() invoked on it)
+function mcl_cauldrons.add_item_proxy(proxy)
+	if table.indexof(mcl_cauldrons.item_proxies, proxy) == -1 then
+		-- insert at front so newer proxies override older ones.
+		table.insert(mcl_cauldrons.item_proxies, 1, proxy)
+	end
+end
+
+--- Invoke applying item to cauldron node.
+--
+-- carry out all the duties of on_rightclick().
+-- @return ItemStack: item to be wielded in hand (may be same `itemstack`).
+function mcl_cauldrons.apply_item(pos, node, user, itemstack)
+	for _, item_handler in ipairs(mcl_cauldrons.item_proxies) do
+		local handled, retval = item_handler:do_apply(pos, node, user, itemstack)
+		if handled then return retval end
+	end
+	return itemstack
+end
+
+function mcl_cauldrons.node_fill_levels(node, change_levels, substance)
+	-- base rules for filling cauldrons.
+	if change_levels <= 0 then
+		-- no change.
+		return nil
+	end
+	local old_level = mcl_cauldrons.node_get_level(node)
+	local whole, fraction = math.modf(change_levels)
+	local new_level
+	if fraction > 0 then
+		if math.random() < fraction then
+			whole = whole + 1
+		end
+	end
+	if (substance and mcl_cauldrons.node_has_substance(node, substance)) or (substance == nil) then
+		-- same substance, add more.
+		new_level = old_level + whole
+	else
+		-- different substance, delete old content.
+		new_level = whole
+	end
+	-- clamp 0 through 3 inclusive.
+	new_level = math.max(0, math.min(new_level, 3))
+	if substance == nil then
+		substance = mcl_cauldrons.node_get_substance(node)
+	end
+	return mcl_cauldrons.node_set_content(node, substance, new_level)
+end
+
+function mcl_cauldrons.node_drain_levels(node, change_levels, substance)
+	-- base rules for draining cauldrons.
+	if change_levels <= 0 then
+		-- no change.
+		return nil
+	end
+	if (substance and not mcl_cauldrons.node_has_substance(node, substance)) then
+		-- different substance, cannot drain.
+		return nil
+	end
+	local old_level = mcl_cauldrons.node_get_level(node)
+	local whole, fraction = math.modf(change_levels)
+	local new_level
+	if fraction > 0 then
+		if math.random() < fraction then
+			whole = whole + 1
+		end
+	end
+	if (whole > old_level) then
+		-- insufficient amount, no change.
+		return nil
+	end
+	-- same substance, drain.
+	new_level = old_level - whole
+	-- clamp 0 through 3 inclusive.
+	new_level = math.max(0, math.min(new_level, 3))
+	if substance == nil then
+		substance = mcl_cauldrons.node_get_substance(node)
+	end
+	return mcl_cauldrons.node_set_content(node, substance, new_level)
+end
+

mods/ITEMS/mcl_cauldrons/cauldron_lava.lua

@@ -0,0 +1,72 @@
+
+-- lava cauldron as extension of empty cauldron.
+mcl_cauldrons.register_cauldron_node("mcl_cauldrons:cauldron_lava_1",
+	merge_tables(mcl_cauldrons.registered_cauldrons["mcl_cauldrons:cauldron"], {
+	description = S("Cauldron (1/3 Lava)"),
+	groups = {
+		pickaxey = 1,
+		cauldron = 1,
+		cauldron_filled = 1,
+		cauldron_maximum = 3,
+		},
+	node_box = mcl_cauldrons.cauldron_nodeboxes[1],
+	collision_box = mcl_cauldrons.cauldron_nodeboxes[0],
+	tiles = {
+		[1]="(default_lava_source_animated.png^[verticalframe:16:0)^mcl_cauldrons_cauldron_top.png",
+	},
+	drop = "mcl_cauldrons:cauldron",
+	_mcl_cauldron_substance = "lava",
+}), "mcl_cauldrons:cauldron")
+
+-- lava cauldron 2/3 as extension of 1/3.
+mcl_cauldrons.register_cauldron_node("mcl_cauldrons:cauldron_lava_2",
+	merge_tables(mcl_cauldrons.registered_cauldrons["mcl_cauldrons:cauldron_lava_1"], {
+	description = S("Cauldron (2/3 Lava)"),
+	groups = {
+		cauldron_filled = 2,
+		},
+	node_box = mcl_cauldrons.cauldron_nodeboxes[2],
+}), "mcl_cauldrons:cauldron")
+
+-- lava cauldron 3/3 as extension of 1/3.
+local LIGHT_LAVA = minetest.registered_nodes["mcl_core:lava_source"].light_source
+mcl_cauldrons.register_cauldron_node("mcl_cauldrons:cauldron_lava_3",
+	merge_tables(mcl_cauldrons.registered_cauldrons["mcl_cauldrons:cauldron_lava_1"], {
+	description = S("Cauldron (3/3 Lava)"),
+	groups = {
+		cauldron_filled = 3,
+		},
+	paramtype = "light",
+	light_source = LIGHT_LAVA,
+	node_box = mcl_cauldrons.cauldron_nodeboxes[3],
+}), "mcl_cauldrons:cauldron")
+
+
+
+-- Bucket interaction, lava.
+
+local BucketProxy = mcl_cauldrons.BucketProxy
+
+function BucketProxy.is_lava(itemstack)
+	if itemstack:get_name() == "mcl_buckets:bucket_lava" then return true end
+	-- other tests.
+end
+
+function BucketProxy:sound_lava(new_itemstack, new_cauldron_node)
+	local nodedef = minetest.registered_nodes["mcl_core:lava_source"]
+	if self.is_empty(new_itemstack) then
+		-- lava placed.
+		return nodedef.sounds.place, { pitch = 1.0 + math.random(-10, 10) * .005 }
+	else
+		-- lava taken.
+		return nodedef.sounds.dug, { pitch = 1.0 + math.random(-10, 10) * .005 }
+	end
+end
+
+function BucketProxy.make_lava(old_itemstack, cauldron_node)
+	return ItemStack("mcl_buckets:bucket_lava")
+end
+
+
+BucketProxy:add_bucket_rules("lava", BucketProxy.is_lava, BucketProxy.make_lava, BucketProxy.sound_lava)
+

mods/ITEMS/mcl_cauldrons/cauldron_river_water.lua

@@ -0,0 +1,75 @@
+
+-- river water cauldron as extension of empty cauldron.
+mcl_cauldrons.register_cauldron_node("mcl_cauldrons:cauldron_river_water_1",
+	merge_tables(mcl_cauldrons.registered_cauldrons["mcl_cauldrons:cauldron"], {
+	description = S("Cauldron (1/3 River Water)"),
+	groups = {
+		pickaxey = 1,
+		cauldron = 1,
+		cauldron_filled = 1,
+		cauldron_maximum = 3,
+		},
+	node_box = mcl_cauldrons.cauldron_nodeboxes[1],
+	collision_box = mcl_cauldrons.cauldron_nodeboxes[0],
+	tiles = {
+		[1]="(default_river_water_source_animated.png^[verticalframe:16:0)^mcl_cauldrons_cauldron_top.png",
+	},
+	drop = "mcl_cauldrons:cauldron",
+	_mcl_cauldron_substance = "river_water",
+}), "mcl_cauldrons:cauldron")
+-- water cauldron 2/3 as extension of 1/3.
+mcl_cauldrons.register_cauldron_node("mcl_cauldrons:cauldron_river_water_2",
+	merge_tables(mcl_cauldrons.registered_cauldrons["mcl_cauldrons:cauldron_river_water_1"], {
+	description = S("Cauldron (2/3 River Water)"),
+	groups = {
+		cauldron_filled = 2,
+		},
+	node_box = mcl_cauldrons.cauldron_nodeboxes[2],
+}), "mcl_cauldrons:cauldron")
+-- water cauldron 3/3 as extension of 1/3.
+mcl_cauldrons.register_cauldron_node("mcl_cauldrons:cauldron_river_water_3",
+	merge_tables(mcl_cauldrons.registered_cauldrons["mcl_cauldrons:cauldron_river_water_1"], {
+	description = S("Cauldron (3/3 River Water)"),
+	groups = {
+		cauldron_filled = 3,
+		},
+	node_box = mcl_cauldrons.cauldron_nodeboxes[3],
+}), "mcl_cauldrons:cauldron")
+
+
+-- bucket interactions, river water.
+
+local BucketProxy = mcl_cauldrons.BucketProxy
+
+function BucketProxy.is_river_water(itemstack)
+	if (itemstack:get_name() == "mcl_buckets:bucket_river_water") then return true end
+	-- other tests.
+end
+
+function BucketProxy.make_river_water(itemstack, cauldron_node)
+	for scan_name, scan_def in pairs(minetest.registered_items) do
+		-- TODO: expand mcl_buckets node definitions.
+	end
+end
+
+
+BucketProxy:add_bucket_rules("river_water", BucketProxy.is_river_water, "mcl_buckets:bucket_river_water", BucketProxy.sound_water)
+
+
+
+-- bottle interactions, river water.
+
+local BottleProxy = mcl_cauldrons.BottleProxy
+
+function BottleProxy.is_river_water(itemstack)
+	if (itemstack:get_name() == "mcl_potions:river_water") then return true end
+	-- other tests.
+end
+
+function BottleProxy.make_river_water(old_itemstack, cauldron_node)
+	return ItemStack("mcl_potions:river_water")
+end
+
+
+BottleProxy:add_bottle_rules("river_water", BottleProxy.is_river_water, "mcl_potions:bottle_river_water", BottleProxy.sound_water)
+

mods/ITEMS/mcl_cauldrons/config.ld

@@ -0,0 +1,8 @@
+-- LDoc (LuaDoc derivative) configuration; not a linker script.
+-- $ luarocks install --local ldoc markdown
+
+project = 'mcl_cauldrons'
+file = { 'api.lua', 'cauldron_lava.lua', 'cauldron_river_water.lua', 'init.lua', 'register.lua' }
+all = true
+format = 'markdown'
+

mods/ITEMS/mcl_cauldrons/doc/index.html

@@ -0,0 +1,69 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
+   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html>
+<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
+<head>
+    <title>Reference</title>
+    <link rel="stylesheet" href="ldoc.css" type="text/css" />
+</head>
+<body>
+
+<div id="container">
+
+<div id="product">
+	<div id="product_logo"></div>
+	<div id="product_name"><big><b></b></big></div>
+	<div id="product_description"></div>
+</div> <!-- id="product" -->
+
+
+<div id="main">
+
+
+<!-- Menu -->
+
+<div id="navigation">
+<br/>
+<h1>mcl_cauldrons</h1>
+
+
+
+
+<h2>Modules</h2>
+<ul class="nowrap">
+  <li><a href="modules/api.html">api</a></li>
+  <li><a href="modules/init.html">init</a></li>
+  <li><a href="modules/register.html">register</a></li>
+</ul>
+
+</div>
+
+<div id="content">
+
+
+
+<h2>Modules</h2>
+<table class="module_list">
+	<tr>
+		<td class="name"  nowrap><a href="modules/api.html">api</a></td>
+		<td class="summary">API for Cauldrons in MineClone2.</td>
+	</tr>
+	<tr>
+		<td class="name"  nowrap><a href="modules/init.html">init</a></td>
+		<td class="summary">Initialization (primary entry point) for mcl_cauldrons.</td>
+	</tr>
+	<tr>
+		<td class="name"  nowrap><a href="modules/register.html">register</a></td>
+		<td class="summary">Base cauldron types.</td>
+	</tr>
+</table>
+
+</div> <!-- id="content" -->
+</div> <!-- id="main" -->
+<div id="about">
+<i>generated by <a href="http://github.com/stevedonovan/LDoc">LDoc 1.4.6</a></i>
+<i style="float:right;">Last updated 2021-11-12 11:20:21 </i>
+</div> <!-- id="about" -->
+</div> <!-- id="container" -->
+</body>
+</html>

mods/ITEMS/mcl_cauldrons/doc/ldoc.css

@@ -0,0 +1,303 @@
+/* BEGIN RESET
+
+Copyright (c) 2010, Yahoo! Inc. All rights reserved.
+Code licensed under the BSD License:
+http://developer.yahoo.com/yui/license.html
+version: 2.8.2r1
+*/
+html {
+    color: #000;
+    background: #FFF;
+}
+body,div,dl,dt,dd,ul,ol,li,h1,h2,h3,h4,h5,h6,pre,code,form,fieldset,legend,input,button,textarea,p,blockquote,th,td {
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+}
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+    text-decoration: none;
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+    margin-left: 20px;
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+input,button,textarea,select {*font-size:100%;
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+/* END RESET */
+
+body {
+    margin-left: 1em;
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+}
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+
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+
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+
+#container {
+    margin-left: 1em;
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+    background-color: #f0f0f0;
+}
+
+#product {
+    text-align: center;
+    border-bottom: 1px solid #cccccc;
+    background-color: #ffffff;
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+
+#product big {
+    font-size: 2em;
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+
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+    background-color: #f0f0f0;
+    border-left: 2px solid #cccccc;
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+
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+    float: left;
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+    padding: 1em;
+    width: 700px;
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+    clear: both;
+    padding: 5px;
+    border-top: 2px solid #cccccc;
+    background-color: #ffffff;
+}
+
+@media print {
+    body {
+        font: 12pt "Times New Roman", "TimeNR", Times, serif;
+    }
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+
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+    }
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+        margin-left: 2%;
+        margin-right: 2%;
+        background-color: #ffffff;
+    }
+
+    #content {
+        padding: 1em;
+        background-color: #ffffff;
+    }
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+        display: none;
+    }
+    pre.example {
+        font-family: "Andale Mono", monospace;
+        font-size: 10pt;
+        page-break-inside: avoid;
+    }
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+
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+    border-width: 1px;
+    border-style: solid;
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+
+
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+    border-width: 1px;
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+    border-color: #cccccc;
+    border-collapse: collapse;
+}
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+    border-width: 1px;
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+}
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+

mods/ITEMS/mcl_cauldrons/doc/modules/api.html

@@ -0,0 +1,905 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
+   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html>
+<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
+<head>
+    <title>Reference</title>
+    <link rel="stylesheet" href="../ldoc.css" type="text/css" />
+</head>
+<body>
+
+<div id="container">
+
+<div id="product">
+	<div id="product_logo"></div>
+	<div id="product_name"><big><b></b></big></div>
+	<div id="product_description"></div>
+</div> <!-- id="product" -->
+
+
+<div id="main">
+
+
+<!-- Menu -->
+
+<div id="navigation">
+<br/>
+<h1>mcl_cauldrons</h1>
+
+<ul>
+  <li><a href="../index.html">Index</a></li>
+</ul>
+
+<h2>Contents</h2>
+<ul>
+<li><a href="#Functions">Functions</a></li>
+<li><a href="#Tables">Tables</a></li>
+<li><a href="#Fields">Fields</a></li>
+</ul>
+
+
+<h2>Modules</h2>
+<ul class="nowrap">
+  <li><strong>api</strong></li>
+  <li><a href="../modules/init.html">init</a></li>
+  <li><a href="../modules/register.html">register</a></li>
+</ul>
+
+</div>
+
+<div id="content">
+
+<h1>Module <code>api</code></h1>
+<p>API for Cauldrons in MineClone2.</p>
+<p>
+
+</p>
+
+
+<h2><a href="#Functions">Functions</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#mcl_cauldrons.make_cauldron">mcl_cauldrons.make_cauldron (substance, fill_level)</a></td>
+	<td class="summary">Determine registered cauldron satisfying specifications.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#mcl_cauldrons.node_is_cauldron">mcl_cauldrons.node_is_cauldron (node)</a></td>
+	<td class="summary">Test: node describes a cauldron</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#mcl_cauldrons.is_cauldron">mcl_cauldrons.is_cauldron (pos)</a></td>
+	<td class="summary">Test: position holds a cauldron</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#mcl_cauldrons.node_has_substance">mcl_cauldrons.node_has_substance (node, substance)</a></td>
+	<td class="summary">Test: cauldron node contains specified substance</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#mcl_cauldrons.has_substance">mcl_cauldrons.has_substance (pos, substance)</a></td>
+	<td class="summary">Test: cauldron at position contains specified substance</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#mcl_cauldrons.list_substances">mcl_cauldrons.list_substances ()</a></td>
+	<td class="summary">List of supported substances</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#mcl_cauldrons.node_get_substance">mcl_cauldrons.node_get_substance (node)</a></td>
+	<td class="summary">Get substance inside cauldron node</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#mcl_cauldrons.get_substance">mcl_cauldrons.get_substance (pos)</a></td>
+	<td class="summary">Get substance inside cauldron (by position)</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#mcl_cauldrons.node_get_maximum">mcl_cauldrons.node_get_maximum (node)</a></td>
+	<td class="summary">Get maximum number of levels available for cauldron node -> number</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#mcl_cauldrons.node_get_level">mcl_cauldrons.node_get_level (node)</a></td>
+	<td class="summary">Get current level from cauldron node</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#mcl_cauldrons.get_level">mcl_cauldrons.get_level (pos)</a></td>
+	<td class="summary">Get current level of cauldron (by position)</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#mcl_cauldrons.node_is_empty">mcl_cauldrons.node_is_empty (node)</a></td>
+	<td class="summary">Test: cauldron node is empty</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#mcl_cauldrons.is_empty">mcl_cauldrons.is_empty (pos)</a></td>
+	<td class="summary">Test: cauldron is empty (by position)</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#mcl_cauldrons.node_is_full">mcl_cauldrons.node_is_full (node)</a></td>
+	<td class="summary">Test: cauldron node is full</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#mcl_cauldrons.is_full">mcl_cauldrons.is_full (pos)</a></td>
+	<td class="summary">Test: cauldron is full (by position)</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#mcl_cauldrons.node_set_content">mcl_cauldrons.node_set_content (node, substance, fill_level)</a></td>
+	<td class="summary">Convert cauldron node to satisfy content specifications.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#mcl_cauldrons.set_content">mcl_cauldrons.set_content (pos, substance, fill_level)</a></td>
+	<td class="summary">Place cauldron of specified substance and fill level at world position.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#mcl_cauldrons.register_cauldron_node">mcl_cauldrons.register_cauldron_node (nodename, nodedef, doc_alias)</a></td>
+	<td class="summary">Wrapper to register cauldron-specific nodes.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#mcl_cauldrons.add_item_proxy">mcl_cauldrons.add_item_proxy (proxy)</a></td>
+	<td class="summary">Add item proxy class.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#mcl_cauldrons.apply_item">mcl_cauldrons.apply_item (pos, node, user, itemstack)</a></td>
+	<td class="summary">Invoke applying item to cauldron node.</td>
+	</tr>
+</table>
+<h2><a href="#Tables">Tables</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#mcl_cauldrons.registered_cauldrons">mcl_cauldrons.registered_cauldrons</a></td>
+	<td class="summary">Table of registered cauldron nodes, indexed by name.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#mcl_cauldrons.substances">mcl_cauldrons.substances</a></td>
+	<td class="summary">List of recognized substances in cauldron.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#Position">Position</a></td>
+	<td class="summary">Provided for documentation purposes, frequently-used table format.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#Node">Node</a></td>
+	<td class="summary">Provided for documentation purposes, frequently-used table format.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#mcl_cauldrons.item_proxies">mcl_cauldrons.item_proxies</a></td>
+	<td class="summary">List of item proxy classes.</td>
+	</tr>
+</table>
+<h2><a href="#Fields">Fields</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#mcl_cauldrons.BUCKET_FILL_LEVELS">mcl_cauldrons.BUCKET_FILL_LEVELS</a></td>
+	<td class="summary">Levels of cauldron change per bucket.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#mcl_cauldrons.BOTTLE_FILL_LEVELS">mcl_cauldrons.BOTTLE_FILL_LEVELS</a></td>
+	<td class="summary">Levels of cauldron change per bottle (potion).</td>
+	</tr>
+</table>
+
+<br/>
+<br/>
+
+
+    <h2 class="section-header "><a name="Functions"></a>Functions</h2>
+
+    <dl class="function">
+    <dt>
+    <a name = "mcl_cauldrons.make_cauldron"></a>
+    <strong>mcl_cauldrons.make_cauldron (substance, fill_level)</strong>
+    </dt>
+    <dd>
+    Determine registered cauldron satisfying specifications. </p>
+
+<p> Cauldrons are described by two state variables: { substance, fill_level }.</p>
+
+<p> Determine the cauldron node definition from these states.</p>
+
+<p> e.g. <code>make_cauldron(&quot;water&quot;, 2)</code> -> <code>&quot;mcl_cauldrons:cauldron_water_2&quot;</code>
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">substance</span>
+         string : Desired cauldron substance, nil for any substance.
+        </li>
+        <li><span class="parameter">fill_level</span>
+         number : Desired cauldron fill level, nil to match any.
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+        2-value: cauldron node name (string), cauldron node definition (table)
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "mcl_cauldrons.node_is_cauldron"></a>
+    <strong>mcl_cauldrons.node_is_cauldron (node)</strong>
+    </dt>
+    <dd>
+    Test: node describes a cauldron
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">node</span>
+         Node : Cauldron node description (as from minetest.get_node())
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+        boolean: node is a cauldron
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "mcl_cauldrons.is_cauldron"></a>
+    <strong>mcl_cauldrons.is_cauldron (pos)</strong>
+    </dt>
+    <dd>
+    Test: position holds a cauldron
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">pos</span>
+         Position : World position (as passed to minetest.get_node())
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+        boolean: a cauldron is at position
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "mcl_cauldrons.node_has_substance"></a>
+    <strong>mcl_cauldrons.node_has_substance (node, substance)</strong>
+    </dt>
+    <dd>
+    Test: cauldron node contains specified substance
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">node</span>
+         Node : Cauldron node description
+        </li>
+        <li><span class="parameter">substance</span>
+         string : substance that should be present in cauldron.
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+        boolean
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "mcl_cauldrons.has_substance"></a>
+    <strong>mcl_cauldrons.has_substance (pos, substance)</strong>
+    </dt>
+    <dd>
+    Test: cauldron at position contains specified substance
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">pos</span>
+         Position : World position
+        </li>
+        <li><span class="parameter">substance</span>
+         string : substance that should be present in cauldron
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+        boolean
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "mcl_cauldrons.list_substances"></a>
+    <strong>mcl_cauldrons.list_substances ()</strong>
+    </dt>
+    <dd>
+    List of supported substances
+
+
+
+    <h3>Returns:</h3>
+    <ol>
+
+        table: List of substances
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "mcl_cauldrons.node_get_substance"></a>
+    <strong>mcl_cauldrons.node_get_substance (node)</strong>
+    </dt>
+    <dd>
+    Get substance inside cauldron node
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">node</span>
+         Node : Cauldron node description
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+        <li>
+        string : Substance inside cauldron</li>
+        <li>
+        <code>nil</code>: Cauldron is empty</li>
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "mcl_cauldrons.get_substance"></a>
+    <strong>mcl_cauldrons.get_substance (pos)</strong>
+    </dt>
+    <dd>
+    Get substance inside cauldron (by position)
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">pos</span>
+         Position : World position
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+        <li>
+        string: Substance inside cauldron</li>
+        <li>
+        <code>nil</code>: Cauldron is empty</li>
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "mcl_cauldrons.node_get_maximum"></a>
+    <strong>mcl_cauldrons.node_get_maximum (node)</strong>
+    </dt>
+    <dd>
+    Get maximum number of levels available for cauldron node -> number
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">node</span>
+
+
+
+        </li>
+    </ul>
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "mcl_cauldrons.node_get_level"></a>
+    <strong>mcl_cauldrons.node_get_level (node)</strong>
+    </dt>
+    <dd>
+    Get current level from cauldron node
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">node</span>
+         Node : Cauldron node description
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+        number: Typically one of 0,1,2,3
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "mcl_cauldrons.get_level"></a>
+    <strong>mcl_cauldrons.get_level (pos)</strong>
+    </dt>
+    <dd>
+    Get current level of cauldron (by position)
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">pos</span>
+         Position : World position
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+        number: Typically one of 0,1,2,3
+ Get current level of cauldron -> number
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "mcl_cauldrons.node_is_empty"></a>
+    <strong>mcl_cauldrons.node_is_empty (node)</strong>
+    </dt>
+    <dd>
+    Test: cauldron node is empty
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">node</span>
+         Node : Cauldron node description
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+        boolean
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "mcl_cauldrons.is_empty"></a>
+    <strong>mcl_cauldrons.is_empty (pos)</strong>
+    </dt>
+    <dd>
+    Test: cauldron is empty (by position)
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">pos</span>
+         Position : World position
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+        boolean
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "mcl_cauldrons.node_is_full"></a>
+    <strong>mcl_cauldrons.node_is_full (node)</strong>
+    </dt>
+    <dd>
+    Test: cauldron node is full
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">node</span>
+         Node : Cauldron node description
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+        boolean
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "mcl_cauldrons.is_full"></a>
+    <strong>mcl_cauldrons.is_full (pos)</strong>
+    </dt>
+    <dd>
+    Test: cauldron is full (by position)
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">pos</span>
+         Position : World position
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+        boolean
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "mcl_cauldrons.node_set_content"></a>
+    <strong>mcl_cauldrons.node_set_content (node, substance, fill_level)</strong>
+    </dt>
+    <dd>
+    Convert cauldron node to satisfy content specifications. </p>
+
+<p> Cauldron specification is subject to normalization based on substance
+ and fill level (e.g. any substance at level 0 becomes empty cauldron).
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">node</span>
+         Node : node to have its contents changed
+        </li>
+        <li><span class="parameter">substance</span>
+         string : intended cauldron substance
+        </li>
+        <li><span class="parameter">fill_level</span>
+         number : intended fill level
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+        table: new cauldron node
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "mcl_cauldrons.set_content"></a>
+    <strong>mcl_cauldrons.set_content (pos, substance, fill_level)</strong>
+    </dt>
+    <dd>
+    Place cauldron of specified substance and fill level at world position. </p>
+
+<p> Cauldron specification is subject to normalization based on substance
+ and fill level (e.g. any substance at level 0 becomes empty cauldron).
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">pos</span>
+         Position : World position.
+        </li>
+        <li><span class="parameter">substance</span>
+         : string cauldron substance (item def <em>mcl</em>cauldron_substance)
+        </li>
+        <li><span class="parameter">fill_level</span>
+         number : cauldron fill level (typically 0,1,2,3)
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+        table: new cauldron node (as passed to minetest.set_pos())
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "mcl_cauldrons.register_cauldron_node"></a>
+    <strong>mcl_cauldrons.register_cauldron_node (nodename, nodedef, doc_alias)</strong>
+    </dt>
+    <dd>
+    Wrapper to register cauldron-specific nodes.
+ additional bookkeeping specific to mcl_cauldrons.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">nodename</span>
+         string : name of node
+        </li>
+        <li><span class="parameter">nodedef</span>
+         table : node description
+        </li>
+        <li><span class="parameter">doc_alias</span>
+         string : for documentation purposes, alias for this specified node name.
+        </li>
+    </ul>
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "mcl_cauldrons.add_item_proxy"></a>
+    <strong>mcl_cauldrons.add_item_proxy (proxy)</strong>
+    </dt>
+    <dd>
+    Add item proxy class. </p>
+
+<p> ItemProxy classes expose <code>do_apply()</code> that carries out the duties of
+ <code>on_rightclick()</code> (applying itemstack to cauldron node).  This method
+ returns 2 values, a boolean and an ItemStack.
+ The first value is true if no further handling is required (typically
+ interaction is complete), false if it could not handle the interaction.
+ Priority of proxy classes are determined by lateness in <a href="../modules/api.html#mcl_cauldrons.add_item_proxy">add_item_proxy</a> --
+ later additions take priority over earlier ones, allowing for stacked mods
+ to override basal behavior.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">proxy</span>
+         ItemProxy : ItemProxy prototype (to have do_apply() invoked on it)
+        </li>
+    </ul>
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "mcl_cauldrons.apply_item"></a>
+    <strong>mcl_cauldrons.apply_item (pos, node, user, itemstack)</strong>
+    </dt>
+    <dd>
+    Invoke applying item to cauldron node. </p>
+
+<p> carry out all the duties of on_rightclick().
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">pos</span>
+
+
+
+        </li>
+        <li><span class="parameter">node</span>
+
+
+
+        </li>
+        <li><span class="parameter">user</span>
+
+
+
+        </li>
+        <li><span class="parameter">itemstack</span>
+
+
+
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+        ItemStack: item to be wielded in hand (may be same <code>itemstack</code>).
+    </ol>
+
+
+
+
+</dd>
+</dl>
+    <h2 class="section-header "><a name="Tables"></a>Tables</h2>
+
+    <dl class="function">
+    <dt>
+    <a name = "mcl_cauldrons.registered_cauldrons"></a>
+    <strong>mcl_cauldrons.registered_cauldrons</strong>
+    </dt>
+    <dd>
+    Table of registered cauldron nodes, indexed by name.
+ Filled by register<em>cauldron</em>node().
+
+
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "mcl_cauldrons.substances"></a>
+    <strong>mcl_cauldrons.substances</strong>
+    </dt>
+    <dd>
+    List of recognized substances in cauldron.
+ Filled by register<em>cauldron</em>node()
+
+
+
+
+
+    <h3>See also:</h3>
+    <ul>
+         <a href="../modules/api.html#mcl_cauldrons.list_substances">mcl_cauldrons.list_substances</a>
+    </ul>
+
+
+</dd>
+    <dt>
+    <a name = "Position"></a>
+    <strong>Position</strong>
+    </dt>
+    <dd>
+    Provided for documentation purposes, frequently-used table format. </p>
+
+<p> Position in world { x, y, z }
+
+
+    <h3>Fields:</h3>
+    <ul>
+        <li><span class="parameter">x</span>
+
+
+
+        </li>
+        <li><span class="parameter">y</span>
+
+
+
+        </li>
+        <li><span class="parameter">z</span>
+
+
+
+        </li>
+    </ul>
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "Node"></a>
+    <strong>Node</strong>
+    </dt>
+    <dd>
+    Provided for documentation purposes, frequently-used table format. </p>
+
+<p> Node description { name, param1, param2 }, as used by <code>minetest.get_node()</code> and <code>minetest.set_node()</code>
+ (not to be confused with node definition)
+
+
+    <h3>Fields:</h3>
+    <ul>
+        <li><span class="parameter">name</span>
+
+
+
+        </li>
+        <li><span class="parameter">param1</span>
+
+
+
+        </li>
+        <li><span class="parameter">param2</span>
+
+
+
+        </li>
+    </ul>
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "mcl_cauldrons.item_proxies"></a>
+    <strong>mcl_cauldrons.item_proxies</strong>
+    </dt>
+    <dd>
+    List of item proxy classes. </p>
+
+<p> For item interactions (right-click), handlers for items that may interact
+ with cauldron.
+
+
+
+
+
+
+
+</dd>
+</dl>
+    <h2 class="section-header "><a name="Fields"></a>Fields</h2>
+
+    <dl class="function">
+    <dt>
+    <a name = "mcl_cauldrons.BUCKET_FILL_LEVELS"></a>
+    <strong>mcl_cauldrons.BUCKET_FILL_LEVELS</strong>
+    </dt>
+    <dd>
+    Levels of cauldron change per bucket.
+
+
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "mcl_cauldrons.BOTTLE_FILL_LEVELS"></a>
+    <strong>mcl_cauldrons.BOTTLE_FILL_LEVELS</strong>
+    </dt>
+    <dd>
+    Levels of cauldron change per bottle (potion).
+
+
+
+
+
+
+
+</dd>
+</dl>
+
+
+</div> <!-- id="content" -->
+</div> <!-- id="main" -->
+<div id="about">
+<i>generated by <a href="http://github.com/stevedonovan/LDoc">LDoc 1.4.6</a></i>
+<i style="float:right;">Last updated 2021-11-12 11:20:21 </i>
+</div> <!-- id="about" -->
+</div> <!-- id="container" -->
+</body>
+</html>

mods/ITEMS/mcl_cauldrons/doc/modules/init.html

@@ -0,0 +1,288 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
+   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html>
+<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
+<head>
+    <title>Reference</title>
+    <link rel="stylesheet" href="../ldoc.css" type="text/css" />
+</head>
+<body>
+
+<div id="container">
+
+<div id="product">
+	<div id="product_logo"></div>
+	<div id="product_name"><big><b></b></big></div>
+	<div id="product_description"></div>
+</div> <!-- id="product" -->
+
+
+<div id="main">
+
+
+<!-- Menu -->
+
+<div id="navigation">
+<br/>
+<h1>mcl_cauldrons</h1>
+
+<ul>
+  <li><a href="../index.html">Index</a></li>
+</ul>
+
+<h2>Contents</h2>
+<ul>
+<li><a href="#Tables">Tables</a></li>
+<li><a href="#Fields">Fields</a></li>
+<li><a href="#Local_Functions">Local Functions</a></li>
+</ul>
+
+
+<h2>Modules</h2>
+<ul class="nowrap">
+  <li><a href="../modules/api.html">api</a></li>
+  <li><strong>init</strong></li>
+  <li><a href="../modules/register.html">register</a></li>
+</ul>
+
+</div>
+
+<div id="content">
+
+<h1>Module <code>init</code></h1>
+<p>Initialization (primary entry point) for mcl_cauldrons.</p>
+<p> Adds cauldrons to MineClone2.</p>
+
+
+<h2><a href="#Tables">Tables</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#mcl_cauldrons">mcl_cauldrons</a></td>
+	<td class="summary">Mod namespace.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#MODENV">MODENV</a></td>
+	<td class="summary">mod's environment (preserve references to mod's locals for nested dofile)</td>
+	</tr>
+</table>
+<h2><a href="#Fields">Fields</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#S">S</a></td>
+	<td class="summary">Common Minetest idiom for text/string translation function.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#modpath">modpath</a></td>
+	<td class="summary">Path of the current Minetest mod.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#modname">modname</a></td>
+	<td class="summary">Name of current mod.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#modpath">modpath</a></td>
+	<td class="summary">Path of current mod.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#mclx_core">mclx_core</a></td>
+	<td class="summary">Path to <a href="../modules/init.html#mclx_core">mclx_core</a> (test <a href="../modules/init.html#mclx_core">mclx_core</a> is loaded)</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#has_doc">has_doc</a></td>
+	<td class="summary">Path to <code>doc</code> (test <code>doc</code> is loaded)</td>
+	</tr>
+</table>
+<h2><a href="#Local_Functions">Local Functions</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#dosubfile">dosubfile (relpath)</a></td>
+	<td class="summary">Execute dofile using mod's environment.</td>
+	</tr>
+</table>
+
+<br/>
+<br/>
+
+
+    <h2 class="section-header "><a name="Tables"></a>Tables</h2>
+
+    <dl class="function">
+    <dt>
+    <a name = "mcl_cauldrons"></a>
+    <strong>mcl_cauldrons</strong>
+    </dt>
+    <dd>
+    Mod namespace.
+
+
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "MODENV"></a>
+    <strong>MODENV</strong>
+    </dt>
+    <dd>
+    mod's environment (preserve references to mod's locals for nested dofile)
+
+
+    <h3>Fields:</h3>
+    <ul>
+        <li><span class="parameter">S</span>
+         Idiomatic function for text translation
+        </li>
+        <li><span class="parameter">modpath</span>
+         path of current mod
+        </li>
+        <li><span class="parameter">modname</span>
+         name of current mod
+        </li>
+        <li><span class="parameter">mclx_core</span>
+         path to mclx_core (<a href="../modules/init.html#mclx_core">mclx_core</a> is loaded)
+        </li>
+        <li><span class="parameter">has_doc</span>
+         path to doc (<code>doc</code> is loaded)
+        </li>
+    </ul>
+
+
+
+
+
+</dd>
+</dl>
+    <h2 class="section-header "><a name="Fields"></a>Fields</h2>
+
+    <dl class="function">
+    <dt>
+    <a name = "S"></a>
+    <strong>S</strong>
+    </dt>
+    <dd>
+    Common Minetest idiom for text/string translation function.
+
+
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "modpath"></a>
+    <strong>modpath</strong>
+    </dt>
+    <dd>
+    Path of the current Minetest mod.
+
+
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "modname"></a>
+    <strong>modname</strong>
+    </dt>
+    <dd>
+    Name of current mod.
+
+
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "modpath"></a>
+    <strong>modpath</strong>
+    </dt>
+    <dd>
+    Path of current mod.
+
+
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "mclx_core"></a>
+    <strong>mclx_core</strong>
+    </dt>
+    <dd>
+    Path to <a href="../modules/init.html#mclx_core">mclx_core</a> (test <a href="../modules/init.html#mclx_core">mclx_core</a> is loaded)
+
+
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "has_doc"></a>
+    <strong>has_doc</strong>
+    </dt>
+    <dd>
+    Path to <code>doc</code> (test <code>doc</code> is loaded)
+
+
+
+
+
+
+
+</dd>
+</dl>
+    <h2 class="section-header "><a name="Local_Functions"></a>Local Functions</h2>
+
+    <dl class="function">
+    <dt>
+    <a name = "dosubfile"></a>
+    <strong>dosubfile (relpath)</strong>
+    </dt>
+    <dd>
+    Execute dofile using mod's environment. </p>
+
+<p> The environment provided to the the dofile() is that of the current mod's.
+ Present init.lua locals at the same level for other files in this mod.
+ (roughly emulates #include behavior)
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">relpath</span>
+         string: path to a file under current mod path
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+        whatever dofile() returns.
+    </ol>
+
+
+
+
+</dd>
+</dl>
+
+
+</div> <!-- id="content" -->
+</div> <!-- id="main" -->
+<div id="about">
+<i>generated by <a href="http://github.com/stevedonovan/LDoc">LDoc 1.4.6</a></i>
+<i style="float:right;">Last updated 2021-11-12 11:20:21 </i>
+</div> <!-- id="about" -->
+</div> <!-- id="container" -->
+</body>
+</html>

mods/ITEMS/mcl_cauldrons/init.lua

@@ -1,143 +1,66 @@
+--- Initialization (primary entry point) for mcl_cauldrons.
+-- Adds cauldrons to MineClone2.
+
+--- Common Minetest idiom for text/string translation function.
 local S = minetest.get_translator(minetest.get_current_modname())
+--- Path of the current Minetest mod.
+local modpath = minetest.get_modpath(minetest.get_current_modname())
 
--- Cauldron mod, adds cauldrons.
+--- Mod namespace.
+mcl_cauldrons = {}
 
--- TODO: Extinguish fire of burning entities
 
--- Convenience function because the cauldron nodeboxes are very similar
-local create_cauldron_nodebox = function(water_level)
-	local floor_y
-	if water_level == 0 then	-- empty
-		floor_y = -0.1875
-	elseif water_level == 1 then	-- 1/3 filled
-		floor_y = 1/16
-	elseif water_level == 2 then	-- 2/3 filled
-		floor_y = 4/16
-	elseif water_level == 3 then	-- full
-		floor_y = 7/16
-	end
-	return {
-		type = "fixed",
-		fixed = {
-			{-0.5, -0.1875, -0.5, -0.375, 0.5, 0.5}, -- Left wall
-			{0.375, -0.1875, -0.5, 0.5, 0.5, 0.5}, -- Right wall
-			{-0.375, -0.1875, 0.375, 0.375, 0.5, 0.5}, -- Back wall
-			{-0.375, -0.1875, -0.5, 0.375, 0.5, -0.375}, -- Front wall
-			{-0.5, -0.3125, -0.5, 0.5, floor_y, 0.5}, -- Floor
-			{-0.5, -0.5, -0.5, -0.375, -0.3125, -0.25}, -- Left front foot, part 1
-			{-0.375, -0.5, -0.5, -0.25, -0.3125, -0.375}, -- Left front foot, part 2
-			{-0.5, -0.5, 0.25, -0.375, -0.3125, 0.5}, -- Left back foot, part 1
-			{-0.375, -0.5, 0.375, -0.25, -0.3125, 0.5}, -- Left back foot, part 2
-			{0.375, -0.5, 0.25, 0.5, -0.3125, 0.5}, -- Right back foot, part 1
-			{0.25, -0.5, 0.375, 0.375, -0.3125, 0.5}, -- Right back foot, part 2
-			{0.375, -0.5, -0.5, 0.5, -0.3125, -0.25}, -- Right front foot, part 1
-			{0.25, -0.5, -0.5, 0.375, -0.3125, -0.375}, -- Right front foot, part 2
-		}
+--- Name of current mod.
+local modname = minetest.get_current_modname()
+--- Path of current mod.
+local modpath = minetest.get_modpath(modname)
+--- Path to `mclx_core` (test `mclx_core` is loaded)
+local mclx_core = minetest.get_modpath("mclx_core")
+--- Path to `doc` (test `doc` is loaded)
+local has_doc = minetest.get_modpath("doc")
+--- mod's environment (preserve references to mod's locals for nested dofile)
+-- @field S Idiomatic function for text translation
+-- @field modpath path of current mod
+-- @field modname name of current mod
+-- @field mclx_core path to mclx_core (`mclx_core` is loaded)
+-- @field has_doc path to doc (`doc` is loaded)
+local MODENV = {
+    S = S,
+    modpath = modpath,
+    modname = modname,
+    mclx_core = mclx_core,
+    has_doc = has_doc,
 }
+MODENV.MODENV = MODENV
+setmetatable(MODENV, {__index=_G}) -- chain to global.
+
+--- Execute dofile using mod's environment.
+--
+-- The environment provided to the the dofile() is that of the current mod's.
+-- Present init.lua locals at the same level for other files in this mod.
+-- (roughly emulates #include behavior)
+--
+-- @param relpath string: path to a file under current mod path
+-- @return whatever dofile() returns.
+local function dosubfile(relpath)
+    -- present mod-local environment to nested subfile.
+    if setfenv then
+        -- Lua 5.1
+        local submodule, err = loadfile(modpath .. "/" .. relpath)
+        if err then
+            error(err)
         end
-
-local cauldron_nodeboxes = {}
-for w=0,3 do
-	cauldron_nodeboxes[w] = create_cauldron_nodebox(w)
-end
-
-
--- Empty cauldron
-minetest.register_node("mcl_cauldrons:cauldron", {
-	description = S("Cauldron"),
-	_tt_help = S("Stores water"),
-	_doc_items_longdesc = S("Cauldrons are used to store water and slowly fill up under rain."),
-	_doc_items_usagehelp = S("Place a water bucket into the cauldron to fill it with water. Place an empty bucket on a full cauldron to retrieve the water. Place a water bottle into the cauldron to fill the cauldron to one third with water. Place a glass bottle in a cauldron with water to retrieve one third of the water."),
-	wield_image = "mcl_cauldrons_cauldron.png",
-	inventory_image = "mcl_cauldrons_cauldron.png",
-	use_texture_alpha = minetest.features.use_texture_alpha_string_modes and "opaque" or false,
-	drawtype = "nodebox",
-	paramtype = "light",
-	is_ground_content = false,
-	groups = {pickaxey=1, deco_block=1, cauldron=1},
-	node_box = cauldron_nodeboxes[0],
-	selection_box = { type = "regular" },
-	tiles = {
-		"mcl_cauldrons_cauldron_inner.png^mcl_cauldrons_cauldron_top.png",
-		"mcl_cauldrons_cauldron_inner.png^mcl_cauldrons_cauldron_bottom.png",
-		"mcl_cauldrons_cauldron_side.png"
-	},
-	sounds = mcl_sounds.node_sound_metal_defaults(),
-	_mcl_hardness = 2,
-	_mcl_blast_resistance = 2,
-})
-
--- Template function for cauldrons with water
-local register_filled_cauldron = function(water_level, description, river_water)
-	local id = "mcl_cauldrons:cauldron_"..water_level
-	local water_tex
-	if river_water then
-		id = id .. "r"
-		water_tex = "default_river_water_source_animated.png^[verticalframe:16:0"
+        setfenv(submodule, MODENV)
+        return submodule()
     else
-		water_tex = "default_water_source_animated.png^[verticalframe:16:0"
-	end
-	minetest.register_node(id, {
-		description = description,
-		_doc_items_create_entry = false,
-		use_texture_alpha = minetest.features.use_texture_alpha_string_modes and "opaque" or false,
-		drawtype = "nodebox",
-		paramtype = "light",
-		is_ground_content = false,
-		groups = {pickaxey=1, not_in_creative_inventory=1, cauldron=(1+water_level), cauldron_filled=water_level, comparator_signal=water_level},
-		node_box = cauldron_nodeboxes[water_level],
-		collision_box = cauldron_nodeboxes[0],
-		selection_box = { type = "regular" },
-		tiles = {
-			"("..water_tex..")^mcl_cauldrons_cauldron_top.png",
-			"mcl_cauldrons_cauldron_inner.png^mcl_cauldrons_cauldron_bottom.png",
-			"mcl_cauldrons_cauldron_side.png"
-		},
-		sounds = mcl_sounds.node_sound_metal_defaults(),
-		drop = "mcl_cauldrons:cauldron",
-		_mcl_hardness = 2,
-		_mcl_blast_resistance = 2,
-	})
-
-	-- Add entry aliases for the Help
-	if minetest.get_modpath("doc") then
-		doc.add_entry_alias("nodes", "mcl_cauldrons:cauldron", "nodes", id)
+        -- Lua 5.2+
+        return dofile(modpath .. "/" .. relpath, "bt", MODENV)
     end
 end
 
--- Filled cauldrons (3 levels)
-register_filled_cauldron(1, S("Cauldron (1/3 Water)"))
-register_filled_cauldron(2, S("Cauldron (2/3 Water)"))
-register_filled_cauldron(3, S("Cauldron (3/3 Water)"))
+MODENV.dosubfile = dosubfile
 
-if minetest.get_modpath("mclx_core") then
-	register_filled_cauldron(1, S("Cauldron (1/3 River Water)"), true)
-	register_filled_cauldron(2, S("Cauldron (2/3 River Water)"), true)
-	register_filled_cauldron(3, S("Cauldron (3/3 River Water)"), true)
-end
 
-minetest.register_craft({
-	output = "mcl_cauldrons:cauldron",
-	recipe = {
-		{ "mcl_core:iron_ingot", "", "mcl_core:iron_ingot" },
-		{ "mcl_core:iron_ingot", "", "mcl_core:iron_ingot" },
-		{ "mcl_core:iron_ingot", "mcl_core:iron_ingot", "mcl_core:iron_ingot" },
-	}
-})
+dofile(modpath.."/api.lua")
+dosubfile("register.lua")
 
-minetest.register_abm({
-	label = "cauldrons",
-	nodenames = {"group:cauldron_filled"},
-	interval = 0.5,
-	chance = 1,
-	action = function(pos, node)
-		for _, obj in pairs(minetest.get_objects_inside_radius(pos, 0.4)) do
-			if mcl_burning.is_burning(obj) then
-				mcl_burning.extinguish(obj)
-				local new_group = minetest.get_item_group(node.name, "cauldron_filled") - 1
-				minetest.swap_node(pos, {name = "mcl_cauldrons:cauldron" .. (new_group == 0 and "" or "_" .. new_group)})
-				break
-			end
-		end
-	end
-})

mods/ITEMS/mcl_cauldrons/mod.conf

@@ -1,3 +1,4 @@
 name = mcl_cauldrons
-depends = mcl_core, mcl_sounds
-optional_depends = mclx_core, doc
+description = Add cauldrons to mcl
+depends = mcl_core, mcl_sounds, mcl_buckets
+optional_depends = mclx_core, doc, mcl_potions

mods/ITEMS/mcl_cauldrons/register.lua

@@ -0,0 +1,699 @@
+--- Base cauldron types.
+
+--local S = minetest.get_translator(minetest.get_current_modname())
+-- expected to be provided by setfenv/environment.
+
+
+-- Convenience function because the cauldron nodeboxes are very similar
+local floors_table = {
+	[0]=-0.1875,  -- empty
+	[1]=1/16,  -- 1/3 filled
+	[2]=4/16,  -- 2/3 filled
+	[3]=7/16,  -- full
+}
+
+local create_cauldron_nodebox = function(water_level)
+	local floor_y = floors_table[water_level]
+	return {
+		type = "fixed",
+		fixed = {
+			{-0.5, -0.1875, -0.5, -0.375, 0.5, 0.5}, -- Left wall
+			{0.375, -0.1875, -0.5, 0.5, 0.5, 0.5}, -- Right wall
+			{-0.375, -0.1875, 0.375, 0.375, 0.5, 0.5}, -- Back wall
+			{-0.375, -0.1875, -0.5, 0.375, 0.5, -0.375}, -- Front wall
+			{-0.5, -0.3125, -0.5, 0.5, floor_y, 0.5}, -- Floor
+			{-0.5, -0.5, -0.5, -0.375, -0.3125, -0.25}, -- Left front foot, part 1
+			{-0.375, -0.5, -0.5, -0.25, -0.3125, -0.375}, -- Left front foot, part 2
+			{-0.5, -0.5, 0.25, -0.375, -0.3125, 0.5}, -- Left back foot, part 1
+			{-0.375, -0.5, 0.375, -0.25, -0.3125, 0.5}, -- Left back foot, part 2
+			{0.375, -0.5, 0.25, 0.5, -0.3125, 0.5}, -- Right back foot, part 1
+			{0.25, -0.5, 0.375, 0.375, -0.3125, 0.5}, -- Right back foot, part 2
+			{0.375, -0.5, -0.5, 0.5, -0.3125, -0.25}, -- Right front foot, part 1
+			{0.25, -0.5, -0.5, 0.375, -0.3125, -0.375}, -- Right front foot, part 2
+		}
+	}
+end
+
+-- Generate nodeboxes for cauldrons, (0=empty, 1=1/3 filled, 2=2/3 filled, 3=full)
+mcl_cauldrons.cauldron_nodeboxes = {}
+for w=0,3 do
+	mcl_cauldrons.cauldron_nodeboxes[w] = create_cauldron_nodebox(w)
+end
+
+
+--- Merge tables of declarative objects.
+--
+-- The normal Lua means of inheritance uses setmetatable.
+-- For node definitions, minetest.register_node() breaks/overwrite the metatable for its own use.
+-- This function copies in the "old" keys/values, to let them be overwritten by another (newer) table.
+-- Nested tables are recursively merged/copied, so nested keys may be selectively overridden.
+-- Modifying the returned table does not risk mangling the source/parent table.
+-- This workaround happens to work as declarative objects do not change after instantiation.
+--
+-- @return recursively-merged table of first and second arguments
+local function merge_tables(a,b)
+	local result = {}
+	for k,v in pairs(a) do result[k]=v end
+	for k,v in pairs(b) do
+		if type(a[k]) == "table" then
+			-- recursive merge table (with copy).
+			result[k] = merge_tables(a[k], v)
+		else
+			result[k] = v
+		end
+	end
+	return result
+end
+
+MODENV.merge_tables = merge_tables
+
+
+--------
+--------
+
+local ItemProxy = {}
+
+--- Item Proxy (base prototype).
+--
+-- Interaction with items are done through a proxy that presume certain
+-- behaviors of actual/registered items.
+-- The idea is to avoid invoking mod-specific functions by name
+-- (therefore relying on callbacks from node definition),
+-- as mods may be extend, replace, or disable items.
+--
+-- Initial item proxies include:
+--
+--  * BucketProxy - interacting with bucket-like items (change fill level by 3)
+--  * BottleProxy - interacting with bottle-like items (change fill level by 1)
+--  * BannerProxy - banner-like items (wash banner, deplete 1 level)
+mcl_cauldrons.ItemProxy = ItemProxy
+
+function ItemProxy.__call(self, ...)
+	local child = {
+		__index = self,
+		__call = self.__call,
+		rules = {},
+	}
+	setmetatable(child, child)
+	return child
+end
+setmetatable(ItemProxy, ItemProxy)
+
+--- Handle applying (right-clicking) item to cauldron node.
+--
+-- delegated by do_rightclick()
+-- @param pos Position : position of (cauldron) node
+-- @param node Node : cauldron node description
+-- @param user UserRef : user using the item on cauldron node
+-- @param itemstack ItemStack : item wielded by user
+-- @return 2-value: apply succeded (boolean), itemstack to go in hand (ItemStack, may be same `itemstack`)
+function ItemProxy:do_apply(pos, node, user, itemstack)
+	local newnode, newitemstack, sound_specifier
+	newnode, newitemstack, sound_specifier = self:apply_basic_rules(itemstack, node)
+	if not newnode and not newitemstack then
+		return false
+	end
+	-- TODO: fix the redundancy
+	local held_itemstack = self:common_exchange(pos, newnode, user, itemstack, newitemstack)
+	if sound_specifier then
+		local soundspec
+		local soundparm = {}
+		if type(sound_specifier) == "function" then
+			local spec_parm
+			soundspec, spec_parm = sound_specifier(self, newitemstack, node)
+			if not soundspec then return true, held_itemstack end  -- shortcut
+			if spec_parm then
+				soundparm = table.copy(spec_parm)
+			end
+		else
+			soundspec = sound_specifier
+		end
+		if soundspec then
+			-- update position.
+			soundparm.pos = pos
+			minetest.sound_play(soundspec, soundparm, true)
+		end
+	end
+	return true, held_itemstack
+end
+
+
+
+--------
+--------
+
+local RuleBasedItemProxy = ItemProxy()
+
+--- Item Proxy interaction with cauldron defined by rulesets.
+mcl_cauldrons.RuleBasedItemProxy = RuleBasedItemProxy
+
+--- prototype derivation to keep separate .rules
+function RuleBasedItemProxy.__call(self, ...)
+	local child = {
+		__index = self,
+		__call = self.__call,
+		rules = {},
+	}
+	setmetatable(child, child)
+	return child
+end
+
+function RuleBasedItemProxy.add_basic_rule(self, match_substance, match_level, input_constraint, next_substance, next_level, output_specifier, sound_specifier)
+end
+
+--- common one-for-one item exchange
+--
+-- put new_node at pos, and in exchange take 1 from itemstack, and give 1 of new_item to user.
+-- @return ItemStack: new itemstack to replace `itemstack` (may be itself with changes)
+function RuleBasedItemProxy.common_exchange(self, pos, new_node, user, itemstack, new_itemstack)
+	if new_node ~= nil then
+		minetest.set_node(pos, new_node)
+	end
+	if type(new_itemstack) == "string" then
+		new_itemstack = ItemStack(new_itemstack)
+	end
+	if new_itemstack ~= nil then
+		if minetest.is_creative_enabled(user:get_player_name()) then
+			-- creative inventory: add new_itemstack if missing.
+			local inv = user:get_inventory()
+			if not inv:contains_item("main", new_itemstack) then
+				inv:add_item("main", new_itemstack)
+			end
+		else
+			-- survival.
+			if itemstack:get_count() == 1 then
+				-- swap with new item.
+				return new_itemstack
+			else
+				-- subtract one, deposit new_itemstack
+				itemstack:take_item(1)
+				local inv = user:get_inventory()
+				if inv:room_for_item("main", new_itemstack) then
+					-- add to inventory
+					inv:add_item("main", new_itemstack)
+				else
+					-- drop on ground.
+					minetest.add_item(user:get_pos(), new_itemstack)
+				end
+			end
+		end
+	end
+	return itemstack
+end
+
+--- Add item/cauldron exchange rule.
+--
+-- Rule following the basic cauldron fill/empty and bucket fill/empty pattern:
+--
+-- * cauldron consistes of a particular substance and specific level.
+-- * cauldron turns into one of a particular substance and level.
+-- * the one bucket used turns into one bucket of something else.
+--
+-- @param match_substance string : cauldron substance matching this rule (nil means empty)
+-- @param match_level number : cauldron fill level matching this rule (nil means any, true maps to full)
+-- @param input_constraint
+--  * string => exact match with item name to trigger rule.
+--  * function(ItemStack) => predicate given item stack, to trigger rule.
+-- @param next_substance string : new cauldron content (nil means empty)
+-- @param next_level number : new cauldron fill level (true means full, 0 means empty)
+-- @param output_specifier
+--  * string => specific item name to generate after successful rule match
+--  * function(ItemStack, table) => given old item stack and new cauldron node, generate new item stack on rule match
+-- @param sound_specifier
+--  * string => specific item name to play 'place' sound on match rule.
+--  * function(ItemStack, table) => given ItemStack and new cauldron node, return (soundspec, soundparam)
+
+function RuleBasedItemProxy:add_basic_rule(match_substance, match_level, input_constraint, next_substance, next_level, output_specifier, sound_specifier)
+	local rule = {
+		match_substance = match_substance,
+		match_level = match_level,
+		input_constraint = input_constraint,
+		next_substance = next_substance,
+		next_level = next_level,
+		output_specifier = output_specifier,
+		sound_specifier = sound_specifier,
+	}
+	table.insert(self.rules, rule)
+end
+
+-- helper function for determining if a rule matches.
+function RuleBasedItemProxy:_rule_match(rule, itemstack, cauldron_node)
+	if rule.match_substance ~= mcl_cauldrons.node_get_substance(cauldron_node) then
+		return
+	end
+	if rule.match_level ~= nil then
+		local current_level = mcl_cauldrons.node_get_level(cauldron_node)
+		-- `true` as alias for maximum.
+		if rule.match_level == true then
+			if current_level ~= mcl_cauldrons.BUCKET_FILL_LEVELS then
+				return
+			end
+		elseif current_level ~= rule.match_level then
+			return
+		end
+	end
+	-- else match any level.
+	if type(rule.input_constraint) == "string" then
+		-- require exact string match.
+		if itemstack:get_name() ~= rule.input_constraint then return end
+	elseif type(rule.input_constraint) == "function" then
+		-- require item predicate.
+		if not rule.input_constraint(itemstack) then return end
+	end
+	return true
+end
+
+--- Apply basic rules with given ItemStack and cauldron node.
+--
+-- apply basic (patterned) rules to the provided item stack and cauldron node.
+-- @return 3-value: new cauldron node table, new item stack, sound_specifier
+function RuleBasedItemProxy:apply_basic_rules(itemstack, cauldron_node)
+	local match_rule
+	for i, rule in ipairs(self.rules) do
+		if self:_rule_match(rule, itemstack, cauldron_node) then
+			match_rule = rule
+			break
+		end
+	end
+	if not match_rule then return end
+	-- cauldron transition.
+	local next_level = match_rule.next_level
+	if next_level == true then
+		-- `true` as alias for maximum.
+		next_level = mcl_cauldrons.BUCKET_FILL_LEVELS
+	end
+	local newnode = mcl_cauldrons.node_set_content(cauldron_node, match_rule.next_substance, next_level)
+	local newitemstack
+	if type(match_rule.output_specifier) == "string" then
+		-- one particular item
+		newitemstack = ItemStack(match_rule.output_specifier)
+	elseif type(match_rule.output_specifier) == "function" then
+		-- function.
+		newitemstack = match_rule.output_specifier(itemstack, newnode)
+	end
+	return newnode, newitemstack, match_rule.sound_specifier
+end
+
+
+
+-------
+-------
+
+-- Bucket(-like) item proxy.
+
+local BucketProxy = mcl_cauldrons.RuleBasedItemProxy()
+
+--- Bucket-like interaction with cauldron.
+--
+-- * empty bucket: requires full cauldron, produce something bucket, cauldron becomes empty.
+-- * something bucket: requires empty cauldron, produce empty bucket, cauldron becomes full.
+-- * something bucket: requires compatible-liquid cauldron, produce empty bucket, cauldron becomes full.
+mcl_cauldrons.BucketProxy = BucketProxy
+
+-- TODO: expand mcl_buckets node definitions to avoid relying on name matching.
+
+--- Rule's `input_constraint` callback for empty bucket.
+-- @param itemstack ItemStack : item stack to test.
+function BucketProxy.is_empty(itemstack)
+	if (itemstack:get_name() == "mcl_buckets:bucket_empty") then return true end
+	-- other tests.
+end
+
+--- Rule's `input_constraint` callback for water bucket.
+-- @param itemstack ItemStack : item stack to test.
+function BucketProxy.is_water(itemstack)
+	if (itemstack:get_name() == "mcl_buckets:bucket_water") then return true end
+	-- other tests.
+end
+
+
+--- Rule's `sound_specifier` method for water bucket use.
+-- @param new_itemstack ItemStack : item stack produced due to rule match
+-- @param new_cauldron_node Node : cauldron node produced due to rule match
+-- @return 2-value: sound specifier, sound parameter
+function BucketProxy:sound_water(new_itemstack, new_cauldron_node)
+	-- water bucket.
+	local nodedef = minetest.registered_nodes["mcl_core:water_source"]
+	if self.is_empty(new_itemstack) then
+		-- water placed.
+		return nodedef.sounds.place, { pitch = 1 + math.random(-10, 10) * .005 }
+	else
+		-- water taken.
+		return nodedef.sounds.dug, { pitch = 1 + math.random(-10, 10) * .005 }
+	end
+end
+
+--- Rule's `output_specifier` callback for obtaining an empty bucket.
+-- @param old_itemstack ItemStack : item stack provided as input
+-- @param cauldron_node Node : cauldron node produced due to rule match.
+-- @return ItemStack: item stack to be wielded by user
+function BucketProxy.make_empty(old_itemstack, cauldron_node)
+	-- TODO: scan registered items for first matching "empty bucket" criteria
+	for scan_name, scan_def in pairs(minetest.registered_items) do
+		-- TODO: expand mcl_buckets node definitions.
+	end
+end
+
+--- Rule's `output_specifier` callback for obtaining a water bucket.
+-- @param old_itemstack ItemStack : item stack provided as input
+-- @param cauldron_node Node : cauldron node produced due to rule match.
+-- @return ItemStack: item stack to be wielded by user
+function BucketProxy.make_water(old_itemstack, cauldron_node)
+	-- TODO: scan registered items for first matching "empty bucket" criteria
+	for scan_name, scan_def in pairs(minetest.registered_items) do
+		-- TODO: expand mcl_buckets node definitions.
+	end
+end
+
+
+--- Patterned bucket rules.
+--
+-- Buckets fill to full, empty from full.
+-- @param substance string : substance shared between bucket and cauldron
+-- @param filled_input string/function : filled bucket given to cauldron
+-- @param filled_output string/function : filled bucket taken from cauldron
+-- @param sound_specifier string/function : rule's sound specifier
+function BucketProxy:add_bucket_rules(substance, filled_input, filled_output, sound_specifier)
+	local empty = "mcl_buckets:bucket_empty"
+	local empty_output = "mcl_buckets:bucket_empty"
+	-- full stuff cauldron + empty bucket -> empty cauldron, full bucket
+	self:add_basic_rule(substance, true, empty,  nil, 0, filled_output, sound_specifier)
+	-- any level stuff cauldron + stuff bucket -> full stuff cauldron, empty bucket (may waste bucket)
+	self:add_basic_rule(substance, nil, filled_input,  substance, true, empty_output, sound_specifier)
+	-- empty cauldron + stuff bucket -> full stuff cauldron, empty bucket
+	self:add_basic_rule(nil, 0, filled_input,  substance, true, empty_output, sound_specifier)
+	-- other combinations -> do nothing (no interaction)
+end
+
+
+BucketProxy:add_bucket_rules("water", BucketProxy.is_water, "mcl_buckets:bucket_water", BucketProxy.sound_water)
+
+
+-------
+-------
+
+-- Bottle(-like) item proxy.
+
+local BottleProxy = mcl_cauldrons.RuleBasedItemProxy()
+
+--- Bottle-like interaction with Cauldron.
+--
+-- * empty bottle: requires non-empty cauldron, generate something bottle, reduce cauldron level by 1.
+-- * something bottle: empty cauldron or same-liquid cauldron, generate empty bottle, increase cauldron level by 1.
+mcl_cauldrons.BottleProxy = BottleProxy
+
+-- TODO: expand mcl_potions to avoid relying on name comparisons.
+
+--- Rule's `input_constraint` callback for empty bottle.
+-- @param itemstack ItemStack : item stack to test.
+-- @return boolean
+function BottleProxy.is_empty(itemstack)
+	if (itemstack:get_name() == "mcl_potions:glass_bottle") then return true end
+	-- other tests.
+end
+
+--- Rule's `input_constraint` callback for water bottle.
+-- @param itemstack ItemStack : item stack to test.
+-- @return boolean
+function BottleProxy.is_water(itemstack)
+	if (itemstack:get_name() == "mcl_potions:water") then return true end
+	-- other tests.
+end
+
+--- Rule's `sound_specifier` method for water bottle use.
+-- @param new_itemstack ItemStack : item stack produced from rule matching
+-- @param new_cauldron_node Node : cauldron node produced from rule matching
+-- @return 2-value: sound specifier, sound parameter
+function BottleProxy:sound_water(new_itemstack, new_cauldron_node)
+	if self.is_empty(new_itemstack) then
+		return "mcl_potions_bottle_pour"
+	else
+		return "mcl_potions_bottle_fill"
+	end
+end
+
+--- Rule's `output_specifier` function for obtaining empty bottle.
+-- @param old_itemstack ItemStack : item stack as input to rule matching
+-- @param cauldron_node Node : cauldron node produced from rule matching
+-- @return ItemStack: item stack to be wielded by user
+function BottleProxy.make_empty(old_itemstack, cauldron_node)
+	return ItemStack("mcl_potions:glass_bottle")
+end
+
+--- Rule's `output_specifier` function for obtaining water bottle.
+-- @param old_itemstack ItemStack : item stack as input to rule matching
+-- @param cauldron_node Node : cauldron node produced from rule matching
+-- @return ItemStack: item stack to be wielded by user
+function BottleProxy.make_water(old_itemstack, cauldron_node)
+	return ItemStack("mcl_potions:water")
+end
+
+--- Patterned bottle rules.
+--
+-- Bottles fill by 1 level, drain by 1 level, not wasted on full cauldron.
+-- @param substance string : substance shared between bottle and cauldron.
+-- @param filled_input string/function : filled bottle given to cauldron
+-- @param filled_output string/function : filled bottle taken from cauldron
+-- @param sound_specifier string/function : rule's sound specifier
+function BottleProxy:add_bottle_rules(substance, filled_input, filled_output, sound_specifier)
+	local empty_input = self.is_empty
+	local empty_output = self.make_empty
+	-- stuff cauldron + empty bottle -> stuff cauldron less 1, water bottle
+	self:add_basic_rule(substance, 3, empty_input,  substance, 2, filled_output, sound_specifier)
+	self:add_basic_rule(substance, 2, empty_input,  substance, 1, filled_output, sound_specifier)
+	self:add_basic_rule(substance, 1, empty_input,  nil, 0, filled_output, sound_specifier)
+	-- empty cauldron + stuff bottle -> stuff cauldron 1, empty bottle
+	self:add_basic_rule(nil, 0, filled_input,  substance, 1, empty_output, sound_specifier)
+	-- stuff cauldron + stuff bottle -> stuff cauldron plus 1, empty bottle
+	self:add_basic_rule(substance, 1, filled_input,  substance, 2, empty_output, sound_specifier)
+	self:add_basic_rule(substance, 2, filled_input,  substance, 3, empty_output, sound_specifier)
+	-- full cauldron + stuff bottle -> do nothing (do not waste bottle)
+end
+
+
+BottleProxy:add_bottle_rules("water", BottleProxy.is_water, BottleProxy.make_water, BottleProxy.sound_water)
+
+
+-------
+-------
+
+-- Banner item proxy
+
+local BannerProxy = mcl_cauldrons.RuleBasedItemProxy()
+
+--- Banner-like interaction with Cauldron.
+--
+-- * Apply to water cauldron to wash topmost layer.
+-- * Applying causes water cauldron to drop 1 level.
+mcl_cauldrons.BannerProxy = BannerProxy
+
+-- TODO: better predicate tests
+
+--- Rule's `input_constraint` function for banner.
+-- @param itemstack ItemStack : item stack to test.
+-- @return boolean
+function BannerProxy.is_banner(itemstack)
+	if string.sub(itemstack:get_name(), 1, 12) == "mcl_banners:" then
+		return true
+	end
+	-- other tests.
+end
+
+--- Rule's `output_specifier` function for obtaining washed banner.
+--
+-- In the case of banners, the resulting itemstack is the old itemstack with metadata modification (handled by on_wash()).
+-- @param old_itemstack ItemStack : item stack that was input to rule matching.
+-- @param cauldron_node Node : cauldron node produced from rule matching.
+-- @return ItemStack: to be the item wielded by user
+function BannerProxy.wash_banner(old_itemstack, cauldron_node)
+	local nodedef = old_itemstack:get_definition()
+	local washed_itemstack
+	if nodedef._mcl_on_wash then
+		washed_itemstack = nodedef._mcl_on_wash(old_itemstack)
+	else
+		washed_itemstack = old_itemstack
+	end
+	return washed_itemstack
+end
+
+
+--- Patterned banner rules.
+--
+-- Banner washed in cauldron, reduces by 1 level, may waste washing (blank banner washable)
+-- @param substance string : substance consumed from cauldron
+-- @param sound_specifier string/function : rule's sound specifier
+function BannerProxy:add_banner_rules(substance, sound_specifier)
+	self:add_basic_rule(substance, 3, self.is_banner,  substance, 2, self.wash_banner,  sound_specifier)
+	self:add_basic_rule(substance, 2, self.is_banner,  substance, 1, self.wash_banner,  sound_specifier)
+	self:add_basic_rule(substance, 1, self.is_banner,  nil, 0, self.wash_banner,  sound_specifier)
+end
+
+
+BannerProxy:add_banner_rules("water", "mcl_potions_bottle_pour")
+
+
+
+--------
+--------
+
+
+
+
+-- initial item proxies.
+-- FIXME: I don't like where this is buried, considering how crucial it is to enabling item interaction.  -PH
+mcl_cauldrons.add_item_proxy(mcl_cauldrons.BannerProxy)
+if minetest.get_modpath("mcl_potions") then
+	mcl_cauldrons.add_item_proxy(mcl_cauldrons.BottleProxy)
+end
+mcl_cauldrons.add_item_proxy(mcl_cauldrons.BucketProxy)
+
+
+
+
+--------
+--------
+
+
+
+
+--- Empty cauldron node definition
+-- @name mcl_cauldrons:cauldron
+-- @class table
+mcl_cauldrons.register_cauldron_node("mcl_cauldrons:cauldron", {
+	description = S("Cauldron"),
+	_tt_help = S("Stores water"),
+	_doc_items_longdesc = S("Cauldrons are used to store water and slowly fill up under rain."),
+	_doc_items_usagehelp = S("Place a water pucket into the cauldron to fill it with water. Place an empty bucket on a full cauldron to retrieve the water. Place a water bottle into the cauldron to fill the cauldron to one third with water. Place a glass bottle in a cauldron with water to retrieve one third of the water."),
+	wield_image = "mcl_cauldrons_cauldron.png",
+	inventory_image = "mcl_cauldrons_cauldron.png",
+	use_texture_alpha = minetest.features.use_texture_alpha_string_modes and "opaque" or false,
+	drawtype = "nodebox",
+	paramtype = "light",
+	is_ground_content = false,
+	groups = {pickaxey=1, deco_block=1, cauldron=1},
+	node_box = mcl_cauldrons.cauldron_nodeboxes[0],
+	selection_box = { type = "regular" },
+	tiles = {
+		"mcl_cauldrons_cauldron_inner.png^mcl_cauldrons_cauldron_top.png",
+		"mcl_cauldrons_cauldron_inner.png^mcl_cauldrons_cauldron_bottom.png",
+		"mcl_cauldrons_cauldron_side.png"
+	},
+	sounds = mcl_sounds.node_sound_metal_defaults(),
+	_mcl_hardness = 2,
+	_mcl_blast_resistance = 2,
+
+	-- delegated to by mcl_buckets and mcl_potions.
+	on_rightclick = function(place_pos, node, user, itemstack)
+		return mcl_cauldrons.apply_item(place_pos, node, user, itemstack)
+	end,
+})
+
+
+--- Water cauldron (1/3) node definition.
+--
+-- water cauldron as extension of empty cauldron.
+-- @name mcl_cauldrons:cauldron_water_1
+-- @class table
+mcl_cauldrons.register_cauldron_node("mcl_cauldrons:cauldron_water_1",
+	merge_tables(mcl_cauldrons.registered_cauldrons["mcl_cauldrons:cauldron"], {
+	description = S("Cauldron (1/3 Water)"),
+	groups = {
+		pickaxey = 1,
+		cauldron = 1,
+		cauldron_filled = 1,
+		cauldron_maximum = 3,
+		},
+	node_box = mcl_cauldrons.cauldron_nodeboxes[1],
+	collision_box = mcl_cauldrons.cauldron_nodeboxes[0],
+	tiles = {
+		[1]="(default_water_source_animated.png^[verticalframe:16:0)^mcl_cauldrons_cauldron_top.png",
+	},
+	drop = "mcl_cauldrons:cauldron",
+	_mcl_cauldron_substance = "water",
+}), "mcl_cauldrons:cauldron")
+
+--- Water cauldron (2/3) node definition.
+--
+-- water cauldron 2/3 as extension of 1/3.
+-- @name mcl_cauldrons:cauldron_water_2
+-- @class table
+mcl_cauldrons.register_cauldron_node("mcl_cauldrons:cauldron_water_2",
+	merge_tables(mcl_cauldrons.registered_cauldrons["mcl_cauldrons:cauldron_water_1"], {
+	description = S("Cauldron (2/3 Water)"),
+	groups = {
+		cauldron_filled = 2,
+		},
+	node_box = mcl_cauldrons.cauldron_nodeboxes[2],
+}), "mcl_cauldrons:cauldron")
+
+--- Water cauldron (2/3) node definition.
+--
+-- water cauldron 3/3 as extension of 1/3.
+-- @name mcl_cauldrons:cauldron_water_3
+-- @class table
+mcl_cauldrons.register_cauldron_node("mcl_cauldrons:cauldron_water_3",
+	merge_tables(mcl_cauldrons.registered_cauldrons["mcl_cauldrons:cauldron_water_1"], {
+	description = S("Cauldron (3/3 Water)"),
+	groups = {
+		cauldron_filled = 3,
+		},
+	node_box = mcl_cauldrons.cauldron_nodeboxes[3],
+}), "mcl_cauldrons:cauldron")
+
+
+-- River Water Cauldron
+if minetest.get_modpath("mclx_core") then
+	dosubfile("cauldron_river_water.lua")
+end
+
+-- Lava Cauldron
+if minetest.get_modpath("mclx_core") then
+	dosubfile("cauldron_lava.lua")
+end
+
+-- Crafting recipe: Cauldron
+minetest.register_craft({
+	output = "mcl_cauldrons:cauldron",
+	recipe = {
+		{ "mcl_core:iron_ingot", "", "mcl_core:iron_ingot" },
+		{ "mcl_core:iron_ingot", "", "mcl_core:iron_ingot" },
+		{ "mcl_core:iron_ingot", "mcl_core:iron_ingot", "mcl_core:iron_ingot" },
+	}
+})
+
+minetest.register_abm({
+	label = "cauldrons",
+	nodenames = {"group:cauldron_filled"},
+	interval = 0.5,
+	chance = 1,
+	action = function(pos, node)
+		local EXTINGUISHING_RADIUS = 0.4
+		for _, obj in pairs(minetest.get_objects_inside_radius(pos, EXTINGUISHING_RADIUS)) do
+			if mcl_burning.is_burning(obj) then
+				local newnode = mcl_cauldrons.node_drain_levels(node, 1, "water")
+				if node ~= newnode then
+					-- extinguishing requires 1 level of water from cauldron.
+					minetest.swap_node(pos, newnode)
+					mcl_burning.extinguish(obj)
+					break
+				end
+			end
+		end
+	end
+})
+
+
+-- backwards compatibility
+local aliases = {
+	-- key=old/legacy name; value=current name
+	["mcl_cauldrons:cauldron_1"] = "mcl_cauldrons:cauldron_water_1",
+	["mcl_cauldrons:cauldron_2"] = "mcl_cauldrons:cauldron_water_2",
+	["mcl_cauldrons:cauldron_3"] = "mcl_cauldrons:cauldron_water_3",
+	["mcl_cauldrons:cauldron_1r"] = "mcl_cauldrons:cauldron_river_water_1",
+	["mcl_cauldrons:cauldron_2r"] = "mcl_cauldrons:cauldron_river_water_2",
+	["mcl_cauldrons:cauldron_3r"] = "mcl_cauldrons:cauldron_river_water_3",
+}
+for legacy, current in pairs(aliases) do
+	minetest.register_alias(legacy, current)
+end
+

mods/ITEMS/mcl_cauldrons/spec/README.md

@@ -0,0 +1,6 @@
+Unit testing of mcl\_cauldrons using mineunit.
+
+
+$ luarocks install --server=https://luarocks.org/dev --local mineunit
+$ luarocks install busted
+

mods/ITEMS/mcl_cauldrons/spec/fixtures/default.lua

@@ -0,0 +1,19 @@
+
+-- Add some simple nodes
+
+local function register_default(name)
+	minetest.register_node(":default:"..name, {
+		description = name.." description",
+		tiles = name.."_texture.png",
+		buildable_to = false,
+		walkable = true,
+	})
+end
+
+register_default("furnace")
+register_default("stone")
+register_default("stonebrick")
+register_default("sand")
+register_default("sandstone")
+register_default("sandstonebrick")
+register_default("steelblock")

mods/ITEMS/mcl_cauldrons/spec/fixtures/digilines.lua

@@ -0,0 +1,32 @@
+
+-- Simple digilines mod fixture that logs sent messages, works with some simple digiline mods
+
+mineunit:set_modpath("digilines", "spec/fixtures")
+
+_G.digilines = {
+	_msg_log = {},
+	receptor_send = function(pos, rules, channel, msg)
+		table.insert(_G.digilines._msg_log, {
+			pos = pos,
+			rules = rules,
+			channel = channel,
+			msg = msg,
+		})
+	end,
+	rules = {
+		default = {
+			{x=0,  y=0,  z=-1},
+			{x=1,  y=0,  z=0},
+			{x=-1, y=0,  z=0},
+			{x=0,  y=0,  z=1},
+			{x=1,  y=1,  z=0},
+			{x=1,  y=-1, z=0},
+			{x=-1, y=1,  z=0},
+			{x=-1, y=-1, z=0},
+			{x=0,  y=1,  z=1},
+			{x=0,  y=-1, z=1},
+			{x=0,  y=1,  z=-1},
+			{x=0,  y=-1, z=-1}
+		}
+	}
+}

mods/ITEMS/mcl_cauldrons/spec/fixtures/mesecons.lua

@@ -0,0 +1,29 @@
+
+-- Simple mesecons fixture that allows many node registrations requiring mesecons
+
+mineunit:set_modpath("mesecons", "spec/fixtures")
+mineunit:set_modpath("mesecons_mvps", "spec/fixtures")
+
+mesecon = {
+	state = {},
+	rules = {
+		default = {
+			{x =  0, y =  0, z = -1},
+			{x =  1, y =  0, z =  0},
+			{x = -1, y =  0, z =  0},
+			{x =  0, y =  0, z =  1},
+			{x =  1, y =  1, z =  0},
+			{x =  1, y = -1, z =  0},
+			{x = -1, y =  1, z =  0},
+			{x = -1, y = -1, z =  0},
+			{x =  0, y =  1, z =  1},
+			{x =  0, y = -1, z =  1},
+			{x =  0, y =  1, z = -1},
+			{x =  0, y = -1, z = -1},
+		}
+	}
+}
+mesecon = setmetatable(mesecon, {
+	__call = function(self,...) return self end,
+	__index = function(...) return function(...)end end,
+})

mods/ITEMS/mcl_cauldrons/spec/fixtures/minetest.conf

@@ -0,0 +1 @@
+active_block_range = 1

mods/ITEMS/mcl_cauldrons/spec/fixtures/pipeworks.lua

@@ -0,0 +1,21 @@
+
+-- Simple pipeworks fixture with few no-op methods, enough for technic, metatool and jumpdrive
+
+mineunit:set_modpath("pipeworks", "spec/fixtures")
+
+local function noop(t)
+	return setmetatable(t, {
+		__call = function(self,...) return self end,
+		__index = function(...) return function(...)end end,
+	})
+end
+
+local pipeworks = {
+	button_label = "",
+	fs_helpers = {
+		cycling_button = function(...) return "" end
+	},
+	tptube = {},
+}
+pipeworks.tptube = noop(pipeworks.tptube)
+_G.pipeworks = noop(pipeworks)

mods/ITEMS/mcl_cauldrons/spec/mcl_cauldron_spec.lua

@@ -0,0 +1,812 @@
+#!/usr/bin/env mineunit
+
+-- unit test for mcl_cauldrons, using mineunit (https://github.com/S-S-X/mineunit)
+-- quick primer: this runs *outside* of Minetest, with the mineunit executable,
+-- and calls to actual minetest engine calls must be mocked.
+require("mineunit")
+
+mineunit("player")
+mineunit("protection")
+mineunit("common/after")
+mineunit("server")
+mineunit("voxelmanip")
+
+fixture("default")
+fixture("mesecons")
+fixture("digilines")
+fixture("pipeworks")
+
+-- mock mclx_core
+_get_modpath = minetest.get_modpath
+minetest.get_modpath = function(modname)
+	if modname == "mclx_core" then return modname end
+	if modname == "doc" then return modname end
+	if modname == "mcl_buckets" then return modname end
+	if modname == "mcl_potions" then return modname end
+	if modname == "mcl_banners" then return modname end
+	return _get_modpath(modname)
+end
+
+describe("MineClone2 cauldrons test", function()
+	-- mock liquid sources (mock sound)
+	local s_water_source = "mcl_core:water_source"
+	local s_lava_source = "mcl_core:lava_source"
+	local water_source = {
+		sounds = {
+			place = "place",
+			dig = "dig",
+		}
+	}
+	local lava_source = {
+		paramtype = "light",
+		light_source = minetest.LIGHT_MAX,
+		sounds = {
+			place = "place",
+			dig = "dig",
+		}
+	}
+	minetest.registered_nodes[s_water_source] = water_source
+	minetest.registered_nodes[s_lava_source] = lava_source
+
+	-- Mocked functions and objects.
+	if not minetest.features then
+		minetest.features = {}
+		minetest.features.use_texture_alpha_string_modes = true
+	end
+	if not minetest.get_objects_inside_radius then
+		minetest.get_objects_inside_radius = function(pos, radius) return {} end
+	end
+
+	_G.mcl_sounds = {}
+	_G.mcl_sounds.node_sound_metal_defaults = function(...) end
+	_G.doc = {}
+	_G.doc.add_entry_alias = function(...) end
+
+	-- Create world with 100 x 1 x 3 stone layer and 3 nodes high air layer.
+	world.layout({
+		{{{x=0,y=0,z=-1},{x=99,y=0,z=1}}, "default:stone"},
+		{{{x=0,y=1,z=-1},{x=99,y=3,z=1}}, "air"},
+		-- empty cauldrons at start.
+		{ {x=0, y=1, z=-3}, "mcl_cauldrons:cauldron" },
+	})
+
+	-- Load current mod executing init.lua
+	sourcefile("init")
+
+	-- Execute on mods loaded callbacks to finish loading.
+	mineunit:mods_loaded()
+
+	-- Tell mods that 1 minute passed already to execute possible weird minetest.after hacks.
+	mineunit:execute_globalstep(60)
+
+	local Sam = Player("Sam")
+
+	-- Players join before tests begin
+	setup(function()
+		mineunit:execute_on_joinplayer(Sam)
+	end)
+
+	-- Players leave after tests finished
+	teardown(function()
+		mineunit:execute_on_leaveplayer(Sam)
+	end)
+
+	-- Generate placement test for all registered nodes without not_in_creative_inventory group
+	local function placement_test(name, xpos)
+        return function()
+			Sam:get_inventory():set_stack("main", 1, name)
+			Sam:do_place({x=xpos, y=1, z=0})
+        end
+	end
+	local xpos = 0
+	for nodename, def in pairs(minetest.registered_nodes) do
+		if not (def.groups and def.groups.not_in_creative_inventory) then
+			it("wont crash placing "..nodename, placement_test(nodename, xpos))
+			xpos = xpos + 1
+        end
+	end
+
+	--[[
+	it("placed all nodes", function()
+		pending("This test might be too simple for potentially complex operation and fails if node is changed")
+		local index = 0
+		for nodename, def in pairs(minetest.registered_nodes) do
+			if not (def.groups and def.groups.not_in_creative_inventory) then
+				local node = minetest.get_node({x=index, y=1, z=0})
+				assert.equals(node.name, nodename)
+				index = index + 1
+			end
+		end
+	end)
+	]]
+
+	-- abbreviated symbols
+	local s_cauldron0 = "mcl_cauldrons:cauldron"
+	local s_cauldron1 = "mcl_cauldrons:cauldron_water_1"
+	local s_cauldron2 = "mcl_cauldrons:cauldron_water_2"
+	local s_cauldron3 = "mcl_cauldrons:cauldron_water_3"
+	local s_cauldron1r = "mcl_cauldrons:cauldron_river_water_1"
+	local s_cauldron2r = "mcl_cauldrons:cauldron_river_water_2"
+	local s_cauldron3r = "mcl_cauldrons:cauldron_river_water_3"
+	local s_cauldron1l = "mcl_cauldrons:cauldron_lava_1"
+	local s_cauldron2l = "mcl_cauldrons:cauldron_lava_2"
+	local s_cauldron3l = "mcl_cauldrons:cauldron_lava_3"
+	local s_bucket0 = "mcl_buckets:bucket_empty"
+	local s_bucket1 = "mcl_buckets:bucket_water"
+	local s_bucket1r = "mcl_buckets:bucket_river_water"
+	local s_bucket1l = "mcl_buckets:bucket_lava"
+	local s_bottle0 = "mcl_potions:glass_bottle"
+	local s_bottle1 = "mcl_potions:water"
+	local s_bottle1r = "mcl_potions:river_water"
+	local s_banner0 = "mcl_banners:placeholder_banner"
+
+	it("test state normalizer", function()
+		-- test reducing (substance,fill_level) tuples to a valid cauldron.
+		local result
+		-- synonyms for empty cauldron: (empty,any), (any,0)
+		result = mcl_cauldrons.make_cauldron("empty", 0)
+		assert.equals(s_cauldron0, result)
+		result = mcl_cauldrons.make_cauldron("empty", 1)
+		assert.equals(s_cauldron0, result)
+		result = mcl_cauldrons.make_cauldron("empty", 2)
+		assert.equals(s_cauldron0, result)
+		result = mcl_cauldrons.make_cauldron("empty", 3)
+		assert.equals(s_cauldron0, result)
+		result = mcl_cauldrons.make_cauldron("water", 0)
+		assert.equals(s_cauldron0, result)
+		result = mcl_cauldrons.make_cauldron("water", 1)
+		assert.equals(s_cauldron1, result)
+		result = mcl_cauldrons.make_cauldron("water", 2)
+		assert.equals(s_cauldron2, result)
+		result = mcl_cauldrons.make_cauldron("water", 3)
+		assert.equals(s_cauldron3, result)
+	end)
+
+	it("test state transition rules", function()
+		-- test the rules about filling and emptying cauldrons.
+		local node
+		local newnode
+		local cauldron0 = mcl_cauldrons.registered_cauldrons[s_cauldron0]
+		newnode = mcl_cauldrons.node_fill_levels(cauldron0, 1, "water")
+		assert.equals(s_cauldron1, newnode.name)
+		newnode = mcl_cauldrons.node_fill_levels(cauldron0, 2, "water")
+		assert.equals(s_cauldron2, newnode.name)
+		newnode = mcl_cauldrons.node_fill_levels(cauldron0, 3, "water")
+		assert.equals(s_cauldron3, newnode.name)
+
+		local cauldron1 = mcl_cauldrons.registered_cauldrons[s_cauldron1]
+		assert.is.truthy(mcl_cauldrons.node_has_substance(cauldron1, "water"))
+		assert.equals(1, mcl_cauldrons.node_get_level(cauldron1))
+		newnode = mcl_cauldrons.node_fill_levels(cauldron1, 1, "water")
+		assert.equals(s_cauldron2, newnode.name)
+		newnode = mcl_cauldrons.node_fill_levels(cauldron1, 2, "water")
+		assert.equals(s_cauldron3, newnode.name)
+
+		local cauldron2 = mcl_cauldrons.registered_cauldrons[s_cauldron2]
+		newnode = mcl_cauldrons.node_fill_levels(cauldron2, 1, "water")
+		assert.equals(s_cauldron3, newnode.name)
+		newnode = mcl_cauldrons.node_fill_levels(cauldron2, 2, "water")
+		assert.equals(s_cauldron3, newnode.name)
+		newnode = mcl_cauldrons.node_drain_levels(cauldron2, 1, "water")
+		assert.equals(s_cauldron1, newnode.name)
+		newnode = mcl_cauldrons.node_drain_levels(cauldron2, 2, "water")
+		assert.equals(s_cauldron0, newnode.name)
+
+		local cauldron3 = mcl_cauldrons.registered_cauldrons[s_cauldron3]
+		newnode = mcl_cauldrons.node_drain_levels(cauldron3, 1, "water")
+		assert.equals(s_cauldron2, newnode.name)
+		newnode = mcl_cauldrons.node_drain_levels(cauldron3, 2, "water")
+		assert.equals(s_cauldron1, newnode.name)
+		newnode = mcl_cauldrons.node_drain_levels(cauldron3, 3, "water")
+		assert.equals(s_cauldron0, newnode.name)
+		newnode = mcl_cauldrons.node_drain_levels(cauldron3, 4, "water")
+		assert.equals(nil, newnode)
+	end)
+
+
+	----
+	-- helper functions
+
+	-- all cauldron activity at this position.
+	local CAULDRON_POS = { x=0, y=1, z=-3 }
+
+	-- Make sure node (at CAULDRON_POS) is a particular cauldron.
+	local function force_cauldron(nodename)
+		local node = { name=nodename }
+		minetest.set_node(CAULDRON_POS, node)
+		return minetest.get_node(CAULDRON_POS)
+	end
+
+	local function assert_cauldron(nodename)
+		local node = minetest.get_node(CAULDRON_POS)
+		assert.is_not_nil(node)
+		assert.equals(nodename, node.name)
+		return node
+	end
+
+	-- Make sure Sam has, and is wielding, inventory.
+	local function force_inv(itemname)
+		Sam:get_inventory():set_stack("main", 1, itemname)
+		local itemstack = Sam:get_inventory():get_stack("main", 1)
+		return itemstack
+	end
+
+	local function assert_inv(itemname)
+		itemstack = Sam:get_inventory():get_stack("main", 1)
+		assert.equals(itemname, itemstack:get_name())
+		return itemstack
+	end
+
+	-- mimick right-clicking (placing) item onto cauldron at CAULDRON_POS.
+	local function rclick_cauldron()
+		local node = minetest.get_node(CAULDRON_POS)
+		local nodedef = minetest.registered_nodes[node.name]
+		local itemstack = Sam:get_inventory():get_stack("main", 1)
+		-- do_place() not viable as buckets/potions/etc. (and their on_place()) are not loaded in this unit test.
+		local newstack = nodedef.on_rightclick(CAULDRON_POS, node, Sam, itemstack)
+		Sam:get_inventory():set_stack("main", 1, newstack)
+		return newstack
+	end
+
+
+	-- mock buckets
+	local bucket0 = {
+		description="Bucket",
+		groups = { bucket=1 },
+	}
+	local bucket1 = {
+		description="Water Bucket",
+		groups = { bucket=1 },
+	}
+	local bucket1r = {
+		description="River Water Bucket",
+		groups = { bucket=1 },
+	}
+	local bucket1l = {
+		description="Lava Bucket",
+		groups = { bucket=1 },
+	}
+	minetest.registered_items[s_bucket0] = bucket0
+	minetest.registered_items[s_bucket1] = bucket1
+	minetest.registered_items[s_bucket1r] = bucket1r
+
+	describe("apply empty bucket to cauldron", function()
+		----
+		-- test the implementation details (in the spirit of TDD)
+		it(", implementation details", function()
+
+			-- empty + full water cauldron = empty cauldron, water bucket
+			local itemstack0 = ItemStack(s_bucket0)
+
+			local pos = CAULDRON_POS
+			local node = { name=s_cauldron3 }
+			local newnode, newitemstack = mcl_cauldrons.BucketProxy:apply_basic_rules(itemstack0, node)
+			assert.is_not_nil(newnode)
+			assert.is_not_nil(newitemstack)
+			assert.equals(s_cauldron0, newnode.name)
+			assert.equals(s_bucket1, newitemstack:get_name())
+
+			-- empty bucket + 2/3 water cauldron = nil, nil (no change)
+			local node = { name=s_cauldron2 }
+			newnode, newitemstack = mcl_cauldrons.BucketProxy:apply_basic_rules(itemstack0, node)
+			assert.is_nil(newnode)
+			assert.is_nil(newitemstack)
+
+			-- empty bucket + 1/3 water cauldron = nil, nil (no change)
+			local node = { name=s_cauldron1 }
+			newnode, newitemstack = mcl_cauldrons.BucketProxy:apply_basic_rules(itemstack0, node)
+			assert.is_nil(newnode)
+			assert.is_nil(newitemstack)
+
+			-- empty bucket + empty cauldron = nil, nil (no change)
+			local node = { name=s_cauldron0 }
+			newnode, newitemstack = mcl_cauldrons.BucketProxy:apply_basic_rules(itemstack0, node)
+			assert.is_nil(newnode)
+			assert.is_nil(newitemstack)
+
+			-- empty bucket + lava cauldron = empty cauldron, lava bucket
+			local node = { name=s_cauldron3l }
+			newnode, newitemstack = mcl_cauldrons.BucketProxy:apply_basic_rules(itemstack0, node)
+			assert.is_not_nil(newnode)
+			assert.is_not_nil(newitemstack)
+			assert.equals(s_cauldron0, newnode.name)
+			assert.equals(s_bucket1l, newitemstack:get_name())
+		end)
+
+
+		----
+		-- mimick world activity (validate for gameplay)
+		it(", mimick world activity", function()
+
+			force_cauldron(s_cauldron3)
+			local node = assert_cauldron(s_cauldron3)
+			assert.equals(3, mcl_cauldrons.node_get_level(node))
+			-- start with empty bucket.
+			force_inv(s_bucket0)
+			local itemstack = assert_inv(s_bucket0)
+			assert.equals("mcl_buckets:bucket_empty", itemstack:get_name())
+
+			-- apply itemstack (rightclick empty bucket) to cauldron (full water) -> empty cauldron, water bucket.
+			local newstack = rclick_cauldron()
+			assert.not_equals(nil, newstack)
+			assert.equals("mcl_buckets:bucket_water", newstack:get_name())
+			assert_inv(s_bucket1)
+			-- check cauldron node updated properly.
+			assert_cauldron(s_cauldron0)
+
+			-- apply empty bucket to 2/3 cauldron -> (no change)
+			force_cauldron(s_cauldron2)
+			force_inv(s_bucket0)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron2)
+			assert_inv(s_bucket0)
+
+			-- apply empty bucket to 1/3 cauldron -> (no change)
+			force_cauldron(s_cauldron1)
+			force_inv(s_bucket0)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron1)
+			assert_inv(s_bucket0)
+
+			-- apply empty bucket to empty cauldron -> (no change)
+			force_cauldron(s_cauldron0)
+			force_inv(s_bucket0)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron0)
+			assert_inv(s_bucket0)
+
+
+			-- apply empty bucket to full river water cauldron -> empty cauldron, river water bucket
+			force_cauldron(s_cauldron3r)
+			force_inv(s_bucket0)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron0)
+			assert_inv(s_bucket1r)
+
+			-- apply empty bucket to 2/3 river water cauldron -> empty cauldron, river water bucket
+			force_cauldron(s_cauldron2r)
+			force_inv(s_bucket0)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron2r)
+			assert_inv(s_bucket0)
+
+			-- apply empty bucket to 1/3 river water cauldron -> empty cauldron, river water bucket
+			force_cauldron(s_cauldron1r)
+			force_inv(s_bucket0)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron1r)
+			assert_inv(s_bucket0)
+
+
+			-- apply empty bucket to full lava cauldron -> empty cauldron, lava bucket
+			force_cauldron(s_cauldron3l)
+			force_inv(s_bucket0)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron0)
+			assert_inv(s_bucket1l)
+
+			-- apply empty bucket to 2/3 lava cauldron -> empty cauldron, lava bucket
+			force_cauldron(s_cauldron2l)
+			force_inv(s_bucket0)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron2l)
+			assert_inv(s_bucket0)
+
+			-- apply empty bucket to 1/3 lava cauldron -> empty cauldron, lava bucket
+			force_cauldron(s_cauldron1l)
+			force_inv(s_bucket0)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron1l)
+			assert_inv(s_bucket0)
+		end)
+	end)
+
+	describe("apply water bucket to cauldron", function()
+		----
+		-- test the implementation details (gets messy).
+		it(", implementation details", function()
+			local itemstack0 = ItemStack(s_bucket1)
+
+			-- water bucket + empty cauldrons = full water cauldron, empty bucket
+			local pos = CAULDRON_POS
+			local node = { name=s_cauldron0 }
+
+			local newnode, newitemstack = mcl_cauldrons.BucketProxy:apply_basic_rules(itemstack0, node)
+			assert.is_not_nil(newnode)
+			assert.is_not_nil(newitemstack)
+			assert.equals(s_cauldron3, newnode.name)
+			assert.equals(s_bucket0, newitemstack:get_name())
+
+			-- water bucket + 1/3 cauldron = full water cauldron, empty bucket
+			node = { name=s_cauldron1 }
+			local newnode, newitemstack = mcl_cauldrons.BucketProxy:apply_basic_rules(itemstack0, node)
+			assert.equals(s_cauldron3, newnode.name)
+			assert.equals(s_bucket0, newitemstack:get_name())
+
+			-- water bucket + 2/3 cauldron = full water cauldron, empty bucket
+			node = { name=s_cauldron2 }
+			local newnode, newitemstack = mcl_cauldrons.BucketProxy:apply_basic_rules(itemstack0, node)
+			assert.equals(s_cauldron3, newnode.name)
+			assert.equals(s_bucket0, newitemstack:get_name())
+
+			-- water bucket + full cauldron = full water cauldron, empty bucket (wastes the water bucket)
+			node = { name=s_cauldron3 }
+			local newnode, newitemstack = mcl_cauldrons.BucketProxy:apply_basic_rules(itemstack0, node)
+			assert.equals(s_cauldron3, newnode.name)
+			assert.equals(s_bucket0, newitemstack:get_name())
+		end)
+
+		----
+		-- mimick world activity (validate for gameplay)
+
+		it(", mimick world activity", function()
+			-- apply water bucket to full cauldron -> cauldron_water_3, empty bucket (bucket wasted)
+			force_cauldron(s_cauldron3)
+			force_inv(s_bucket1)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron3)
+			assert_inv(s_bucket0)
+
+			-- apply water bucket to 2/3 cauldron -> cauldron_water_3, empty bucket
+			force_cauldron(s_cauldron2)
+			force_inv(s_bucket1)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron3)
+			assert_inv(s_bucket0)
+
+			-- apply water bucket to 1/3 cauldron -> cauldron_water_3, empty bucket
+			force_cauldron(s_cauldron1)
+			force_inv(s_bucket1)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron3)
+			assert_inv(s_bucket0)
+
+			-- apply water bucket to empty cauldron -> cauldron_water_3, empty bucket
+			force_cauldron(s_cauldron0)
+			force_inv(s_bucket1)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron3)
+			assert_inv(s_bucket0)
+		end)
+	end)
+
+	describe("apply river water bucket to cauldron #riverwaterbucket", function()
+		it(", implementation details", function()
+			assert.is_not_nil(minetest.registered_nodes["mcl_cauldrons:cauldron_river_water_1"])
+			assert.is_not_nil(minetest.registered_nodes["mcl_cauldrons:cauldron_river_water_2"])
+			assert.is_not_nil(minetest.registered_nodes["mcl_cauldrons:cauldron_river_water_3"])
+			----
+			-- test the implementation details (gets messy).
+			local itemstack0 = ItemStack(s_bucket1r)
+
+			-- river water bucket + empty cauldrons = full river water cauldron, empty bucket
+			local pos = CAULDRON_POS
+			local node = { name=s_cauldron0 }
+
+			local newnode, newitemstack = mcl_cauldrons.BucketProxy:apply_basic_rules(itemstack0, node)
+			assert.is_not_nil(newnode)
+			assert.is_not_nil(newitemstack)
+			assert.equals(s_cauldron3r, newnode.name)
+			assert.equals(s_bucket0, newitemstack:get_name())
+
+			-- river water bucket + 1/3 cauldron = full river water cauldron, empty bucket
+			node = { name=s_cauldron1r }
+			local newnode, newitemstack = mcl_cauldrons.BucketProxy:apply_basic_rules(itemstack0, node)
+			assert.equals(s_cauldron3r, newnode.name)
+			assert.equals(s_bucket0, newitemstack:get_name())
+
+			-- river water bucket + 2/3 cauldron = full river water cauldron, empty bucket
+			node = { name=s_cauldron2r }
+			local newnode, newitemstack = mcl_cauldrons.BucketProxy:apply_basic_rules(itemstack0, node)
+			assert.equals(s_cauldron3r, newnode.name)
+			assert.equals(s_bucket0, newitemstack:get_name())
+
+			-- river water bucket + full cauldron = full river water cauldron, empty bucket (wastes the river water bucket)
+			node = { name=s_cauldron3r }
+			local newnode, newitemstack = mcl_cauldrons.BucketProxy:apply_basic_rules(itemstack0, node)
+			assert.equals(s_cauldron3r, newnode.name)
+			assert.equals(s_bucket0, newitemstack:get_name())
+		end)
+
+		----
+		-- mimick world activity (validate for gameplay)
+
+		it(", mimick world activity", function()
+			-- apply river water bucket to full cauldron -> cauldron_water_3, empty bucket (bucket wasted)
+			force_cauldron(s_cauldron3r)
+			force_inv(s_bucket1r)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron3r)
+			assert_inv(s_bucket0)
+
+			-- apply river water bucket to 2/3 cauldron -> cauldron_water_3, empty bucket
+			force_cauldron(s_cauldron2r)
+			force_inv(s_bucket1r)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron3r)
+			assert_inv(s_bucket0)
+
+			-- apply river water bucket to 1/3 cauldron -> cauldron_water_3, empty bucket
+			force_cauldron(s_cauldron1r)
+			force_inv(s_bucket1r)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron3r)
+			assert_inv(s_bucket0)
+
+			-- apply river water bucket to empty cauldron -> cauldron_water_3, empty bucket
+			force_cauldron(s_cauldron0)
+			force_inv(s_bucket1r)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron3r)
+			assert_inv(s_bucket0)
+		end)
+	end)
+
+	describe("apply lava bucket to cauldron #lavabucket", function()
+		it(", implementation details", function()
+			assert.is_not_nil(minetest.registered_nodes["mcl_cauldrons:cauldron_lava_1"])
+			assert.is_not_nil(minetest.registered_nodes["mcl_cauldrons:cauldron_lava_2"])
+			assert.is_not_nil(minetest.registered_nodes["mcl_cauldrons:cauldron_lava_3"])
+			----
+			-- test the implementation details (gets messy).
+			local itemstack0 = ItemStack(s_bucket1l)
+
+			-- lava bucket + empty cauldrons = full lava cauldron, empty bucket
+			local pos = CAULDRON_POS
+			local node = { name=s_cauldron0 }
+
+			local newnode, newitemstack = mcl_cauldrons.BucketProxy:apply_basic_rules(itemstack0, node)
+			assert.is_not_nil(newnode)
+			assert.is_not_nil(newitemstack)
+			assert.equals(s_cauldron3l, newnode.name)
+			assert.equals(s_bucket0, newitemstack:get_name())
+
+			-- lava bucket + 1/3 cauldron = full lava cauldron, empty bucket
+			node = { name=s_cauldron1l }
+			local newnode, newitemstack = mcl_cauldrons.BucketProxy:apply_basic_rules(itemstack0, node)
+			assert.equals(s_cauldron3l, newnode.name)
+			assert.equals(s_bucket0, newitemstack:get_name())
+
+			-- lava bucket + 2/3 cauldron = full lava cauldron, empty bucket
+			node = { name=s_cauldron2l }
+			local newnode, newitemstack = mcl_cauldrons.BucketProxy:apply_basic_rules(itemstack0, node)
+			assert.equals(s_cauldron3l, newnode.name)
+			assert.equals(s_bucket0, newitemstack:get_name())
+
+			-- lava bucket + full cauldron = full lava cauldron, empty bucket (wastes the lava bucket)
+			node = { name=s_cauldron3l }
+			local newnode, newitemstack = mcl_cauldrons.BucketProxy:apply_basic_rules(itemstack0, node)
+			assert.equals(s_cauldron3l, newnode.name)
+			assert.equals(s_bucket0, newitemstack:get_name())
+		end)
+
+		----
+		-- mimick world activity (validate for gameplay)
+
+		it(", mimick world activity", function()
+			-- apply lava bucket to full cauldron -> cauldron_water_3, empty bucket (bucket wasted)
+			force_cauldron(s_cauldron3l)
+			force_inv(s_bucket1l)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron3l)
+			assert_inv(s_bucket0)
+
+			-- apply lava bucket to 2/3 cauldron -> cauldron_water_3, empty bucket
+			force_cauldron(s_cauldron2l)
+			force_inv(s_bucket1l)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron3l)
+			assert_inv(s_bucket0)
+
+			-- apply lava bucket to 1/3 cauldron -> cauldron_water_3, empty bucket
+			force_cauldron(s_cauldron1l)
+			force_inv(s_bucket1l)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron3l)
+			assert_inv(s_bucket0)
+
+			-- apply lava bucket to empty cauldron -> cauldron_water_3, empty bucket
+			force_cauldron(s_cauldron0)
+			force_inv(s_bucket1l)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron3l)
+			assert_inv(s_bucket0)
+		end)
+	end)
+
+
+	-- mock potions
+	local bottle0 = {
+		description="Glass Bottle",
+		groups = { potion=1 },
+	}
+	local bottle1 = {
+		description="Water Bottle",
+		groups = { potion=1 },
+	}
+	local bottle1r = {
+		description="River Water Bottle",
+		groups = { potion=1 },
+	}
+	minetest.registered_items[s_bottle0] = bottle0
+	minetest.registered_items[s_bottle1] = bottle1
+	minetest.registered_items[s_bottle1r] = bottle1r
+
+	describe("apply glass/empty bottle to cauldron", function()
+		----
+		-- implementation details
+
+		it(", implementation details", function()
+			-- empty bottle + full cauldron = cauldron_water_2, water bottle
+			local itemstack0 = ItemStack(s_bottle0)
+			local pos = CAULDRON_POS
+			local node = { name=s_cauldron3 }
+			-- force to full cauldron
+			minetest.set_node(pos, node)
+
+			local newnode, newitemstack = mcl_cauldrons.BottleProxy:apply_basic_rules(itemstack0, node)
+			assert.is_not_nil(newnode)
+			assert.equals(s_cauldron2, newnode.name)
+			assert.equals(s_bottle1, newitemstack:get_name())
+
+			-- empty bottle + 2/3 water cauldron = cauldron_water_1, water_bottle
+			node = { name=s_cauldron2 }
+			local newnode, newitemstack = mcl_cauldrons.BottleProxy:apply_basic_rules(itemstack0, node)
+			assert.is_not_nil(newnode)
+			assert.equals("mcl_cauldrons:cauldron_water_1", newnode.name)
+			assert.equals("mcl_potions:water", newitemstack:get_name())
+
+			-- empty bottle + 1/3 water cauldron = empty cauldron, water_bottle
+			node = { name=s_cauldron1 }
+			local newnode, newitemstack = mcl_cauldrons.BottleProxy:apply_basic_rules(itemstack0, node)
+			assert.equals("mcl_cauldrons:cauldron", newnode.name)
+			assert.equals("mcl_potions:water", newitemstack:get_name())
+
+			-- empty bottle + empty cauldron = nil, nil (no changes)
+			node = { name=s_cauldron0 }
+			local newnode, newitemstack = mcl_cauldrons.BottleProxy:apply_basic_rules(itemstack0, node)
+			assert.equals(nil, newnode)
+			assert.equals(nil, newitemstack)
+		end)
+
+		----
+		-- mimick world activity (validate for gameplay)
+		it(", mimick world activity", function()
+
+			-- apply empty bottle to empty cauldron -> (no change)
+			force_cauldron(s_cauldron0)
+			force_inv(s_bottle0)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron0)
+			assert_inv(s_bottle0)
+
+			-- apply empty bottle to 1/3 cauldron -> empty cauldron, water bottle.
+			force_cauldron(s_cauldron1)
+			force_inv(s_bottle0)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron0)
+			assert_inv(s_bottle1)
+
+			-- apply empty bottle to 2/3 cauldron -> cauldron_water_1, water_bottle.
+			force_cauldron(s_cauldron2)
+			force_inv(s_bottle0)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron1)
+			assert_inv(s_bottle1)
+
+			-- apply empty bottle to full cauldron -> cauldron_water_2, water_bottle.
+			force_cauldron(s_cauldron3)
+			force_inv(s_bottle0)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron2)
+			assert_inv(s_bottle1)
+		end)
+	end)
+
+	describe("apply water bottle to cauldron", function()
+		it("water battle vs cauldron implementation details", function()
+			----
+			-- implementation details
+
+			local itemstack0 = ItemStack(s_bottle1)
+			local pos = CAULDRON_POS
+			local node = { name=s_cauldron0 }
+			-- force to empty cauldron
+			minetest.set_node(pos, node)
+
+			-- water bottle + empty cauldron = cauldron_water_1, empty bottle
+			local newnode, newitemstack = mcl_cauldrons.BottleProxy:apply_basic_rules(itemstack0, node)
+			assert.is_not_nil(newnode)
+			assert.equals(s_cauldron1, newnode.name)
+			assert.equals(s_bottle0, newitemstack:get_name())
+
+			-- water bottle + 1/3 water cauldron = cauldron_water_2, empty bottle
+			node = { name=s_cauldron1 }
+			local newnode, newitemstack = mcl_cauldrons.BottleProxy:apply_basic_rules(itemstack0, node)
+			assert.equals(s_cauldron2, newnode.name)
+			assert.equals(s_bottle0, newitemstack:get_name())
+
+			-- water bottle + 2/3 water cauldron = cauldron_water_3, empty bottle
+			node = { name=s_cauldron2 }
+			local newnode, newitemstack = mcl_cauldrons.BottleProxy:apply_basic_rules(itemstack0, node)
+			assert.equals(s_cauldron3, newnode.name)
+			assert.equals(s_bottle0, newitemstack:get_name())
+
+			-- water bottle + full water cauldron = nil, nil (no change)
+			node = { name=s_cauldron3 }
+			local newnode, newitemstack = mcl_cauldrons.BottleProxy:apply_basic_rules(itemstack0, node)
+			assert.equals(nil, newnode)
+			assert.equals(nil, newitemstack)
+		end)
+
+			----
+			-- mimick world activity (validate for gameplay)
+
+		it("water bottle vs cauldron, mimick world activity", function()
+			-- apply water bottle to empty cauldron -> cauldron1, empty bottle
+			force_cauldron(s_cauldron0)
+			force_inv(s_bottle1)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron1)
+			assert_inv(s_bottle0)
+
+			-- apply water bottle to 1/3 cauldron -> cauldron2, empty bottle
+			force_cauldron(s_cauldron1)
+			force_inv(s_bottle1)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron2)
+			assert_inv(s_bottle0)
+
+			-- apply water bottle to 2/3 cauldron -> cauldron3, empty bottle
+			force_cauldron(s_cauldron2)
+			force_inv(s_bottle1)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron3)
+			assert_inv(s_bottle0)
+
+			-- apply water bottle to full cauldron -> (no change)
+			force_cauldron(s_cauldron3)
+			force_inv(s_bottle1)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron3)
+			assert_inv(s_bottle1)
+		end)
+	end)
+
+	-- mock banner
+	local banner0 = {
+		description="Placeholder Banner",
+		groups = { banner=1 },
+	}
+	minetest.registered_items[s_banner0] = banner0
+
+	describe("apply banner to cauldron", function()
+		it(", implementation details", function()
+			local itemstack0 = ItemStack(s_banner0)
+			local node = { name=s_cauldron3 }
+			local newnode, newitem = mcl_cauldrons.BannerProxy:apply_basic_rules(itemstack0, node)
+			assert.is_not_nil(newnode)
+			assert.is_not_nil(newitem)
+		end)
+
+		it(", mimick world activity", function()
+			force_cauldron(s_cauldron3)
+			assert_cauldron(s_cauldron3)
+			force_inv(s_banner0)
+			assert_inv(s_banner0)
+			rclick_cauldron()
+			assert_cauldron(s_cauldron2)
+			assert_inv(s_banner0)
+		end)
+	end)
+
+
+	-- Execute globalstep few times just to see if something happens
+	it("gloabalstep works", function()
+		for _=1,60 do
+			mineunit:execute_globalstep(0.42)
+		end
+	end)
+
+end)
+

mods/ITEMS/mcl_cauldrons/spec/mineunit.conf

@@ -0,0 +1,5 @@
+time_step = 100
+verbose = 3
+exclude = {
+	"integration_test",
+}

mods/ITEMS/mcl_core/functions.lua

@@ -773,8 +773,7 @@ end
 
 local grass_spread_randomizer = PseudoRandom(minetest.get_mapgen_setting("seed"))
 
--- Return appropriate grass block node for pos
-function mcl_core.get_grass_block_type(pos)
+function mcl_core.get_grass_palette_index(pos)
 	local biome_data = minetest.get_biome_data(pos)
 	local index = 0
 	if biome_data then
@@ -785,7 +784,12 @@ function mcl_core.get_grass_block_type(pos)
 			index = reg_biome._mcl_palette_index
 		end
 	end
-	return {name="mcl_core:dirt_with_grass", param2=index}
+	return index
+end
+
+-- Return appropriate grass block node for pos
+function mcl_core.get_grass_block_type(pos)
+	return {name = "mcl_core:dirt_with_grass", param2 = mcl_core.get_grass_palette_index(pos)}
 end
 
 ------------------------------

mods/ITEMS/mcl_core/nodes_base.lua

@@ -365,7 +365,7 @@ minetest.register_node("mcl_core:dirt_with_grass", {
 	overlay_tiles = {"mcl_core_grass_block_top.png", "", {name="mcl_core_grass_block_side_overlay.png", tileable_vertical=false}},
 	palette = "mcl_core_palette_grass.png",
 	palette_index = 0,
-	color = "#55aa60",
+	color = "#8EB971",
 	is_ground_content = true,
 	stack_max = 64,
 	groups = {handy=1,shovely=1,dirt=2,grass_block=1, grass_block_no_snow=1, soil=1, soil_sapling=2, soil_sugarcane=1, cultivatable=2, spreading_dirt_type=1, enderman_takable=1, building_block=1},

mods/ITEMS/mcl_core/nodes_cactuscane.lua

@@ -53,7 +53,10 @@ minetest.register_node("mcl_core:reeds", {
 	_doc_items_longdesc = S("Sugar canes are a plant which has some uses in crafting. Sugar canes will slowly grow up to 3 blocks when they are next to water and are placed on a grass block, dirt, sand, red sand, podzol or coarse dirt. When a sugar cane is broken, all sugar canes connected above will break as well."),
 	_doc_items_usagehelp = S("Sugar canes can only be placed top of other sugar canes and on top of blocks on which they would grow."),
 	drawtype = "plantlike",
+	paramtype2 = "color",
 	tiles = {"default_papyrus.png"},
+	palette = "mcl_core_palette_grass.png",
+	palette_index = 0,
 	inventory_image = "mcl_core_reeds.png",
 	wield_image = "mcl_core_reeds.png",
 	paramtype = "light",
@@ -79,6 +82,7 @@ minetest.register_node("mcl_core:reeds", {
 	groups = {dig_immediate=3, craftitem=1, deco_block=1, plant=1, non_mycelium_plant=1, dig_by_piston=1},
 	sounds = mcl_sounds.node_sound_leaves_defaults(),
 	node_placement_prediction = "",
+	drop = "mcl_core:reeds", -- to prevent color inheritation
 	on_place = mcl_util.generate_on_place_plant_function(function(place_pos, place_node)
 		local soil_pos = {x=place_pos.x, y=place_pos.y-1, z=place_pos.z}
 		local soil_node = minetest.get_node_or_nil(soil_pos)
@@ -114,6 +118,15 @@ minetest.register_node("mcl_core:reeds", {
 		return false
 
 	end),
+	on_construct = function(pos)
+		local node = minetest.get_node(pos)
+		if node.param2 == 0 then
+			node.param2 = mcl_core.get_grass_palette_index(pos)
+			if node.param2 ~= 0 then
+				minetest.set_node(pos, node)
+			end
+		end
+	end,
 	_mcl_blast_resistance = 0,
 	_mcl_hardness = 0,
 })

mods/ITEMS/mcl_dye/API.md

@@ -0,0 +1,14 @@
+# mcl_dye
+
+# Bone meal API
+Callback and particle functions.
+
+## mcl_dye.add_bone_meal_particle(pos, def)
+Spawns standard or custom bone meal particles.
+* `pos`: position, is ignored if you define def.minpos and def.maxpos
+* `def`: (optional) particle definition
+
+## mcl_dye.register_on_bone_meal_apply(function(pointed_thing, user))
+Called when the bone meal is applied anywhere.
+* `pointed_thing`: exact pointing location (see Minetest API), where the bone meal is applied
+* `user`: ObjectRef of the player who aplied the bone meal, can be nil!

mods/ITEMS/mcl_dye/init.lua

@@ -128,26 +128,35 @@ for _, row in ipairs(dyelocal.dyes) do
 end
 
 -- Bone Meal
-local function bone_meal_particle(pos)
+function mcl_dye.add_bone_meal_particle(pos, def)
+	if not def then
+		def = {}
+	end
 	minetest.add_particlespawner({
-		amount = 10,
-		time = 0.1,
-		minpos = { x = pos.x - 0.5, y = pos.y - 0.5, z = pos.z - 0.5 },
-		maxpos = { x = pos.x + 0.5, y = pos.y + 0.5, z = pos.z + 0.5 },
-		minvel = { x = 0, y = 0, z = 0},
-		maxvel = { x = 0, y = 0, z = 0},
-		minacc = { x = 0, y = 0, z = 0},
-		maxacc = { x = 0, y = 0, z = 0},
-		minexptime = 1,
-		maxexptime = 4,
-		minsize = 0.7,
-		maxsize = 2.4,
+		amount = def.amount or 10,
+		time = def.time or 0.1,
+		minpos = def.minpos or vector.subtract(pos, 0.5),
+		maxpos = def.maxpos or vector.add(pos, 0.5),
+		minvel = def.minvel or vector.new(0, 0, 0),
+		maxvel = def.maxvel or vector.new(0, 0, 0),
+		minacc = def.minacc or vector.new(0, 0, 0),
+		maxacc = def.maxacc or vector.new(0, 0, 0),
+		minexptime = def.minexptime or 1,
+		maxexptime = def.maxexptime or 4,
+		minsize = def.minsize or 0.7,
+		maxsize = def.maxsize or 2.4,
 		texture = "mcl_particles_bonemeal.png^[colorize:#00EE00:125", -- TODO: real MC color
-		glow = 5,
+		glow = def.glow or 5,
 	})
 end
 
-function mcl_dye.apply_bone_meal(pointed_thing)
+mcl_dye.bone_meal_callbacks = {}
+
+function mcl_dye.register_on_bone_meal_apply(func)
+	table.insert(mcl_dye.bone_meal_callbacks, func)
+end
+
+local function apply_bone_meal(pointed_thing)
 	-- Bone meal currently spawns all flowers found in the plains.
 	local flowers_table_plains = {
 		"mcl_flowers:dandelion",
@@ -183,14 +192,21 @@ function mcl_dye.apply_bone_meal(pointed_thing)
 	local pos = pointed_thing.under
 	local n = minetest.get_node(pos)
 	if n.name == "" then return false end
+
+	for _, func in pairs(mcl_dye.bone_meal_callbacks) do
+		if func(pointed_thing, user) then
+			return true
+		end
+	end
+
 	if minetest.get_item_group(n.name, "sapling") >= 1 then
-		bone_meal_particle(pos)
+		mcl_dye.add_bone_meal_particle(pos)
 		-- Saplings: 45% chance to advance growth stage
 		if math.random(1,100) <= 45 then
 			return mcl_core.grow_sapling(pos, n)
 		end
 	elseif minetest.get_item_group(n.name, "mushroom") == 1 then
-		bone_meal_particle(pos)
+		mcl_dye.add_bone_meal_particle(pos)
 		-- Try to grow huge mushroom
 
 		-- Must be on a dirt-type block
@@ -240,39 +256,37 @@ function mcl_dye.apply_bone_meal(pointed_thing)
 		return false
 	-- Wheat, Potato, Carrot, Pumpkin Stem, Melon Stem: Advance by 2-5 stages
 	elseif string.find(n.name, "mcl_farming:wheat_") then
-		bone_meal_particle(pos)
+		mcl_dye.add_bone_meal_particle(pos)
 		local stages = math.random(2, 5)
 		return mcl_farming:grow_plant("plant_wheat", pos, n, stages, true)
 	elseif string.find(n.name, "mcl_farming:potato_") then
-		bone_meal_particle(pos)
+		mcl_dye.add_bone_meal_particle(pos)
 		local stages = math.random(2, 5)
 		return mcl_farming:grow_plant("plant_potato", pos, n, stages, true)
 	elseif string.find(n.name, "mcl_farming:carrot_") then
-		bone_meal_particle(pos)
+		mcl_dye.add_bone_meal_particle(pos)
 		local stages = math.random(2, 5)
 		return mcl_farming:grow_plant("plant_carrot", pos, n, stages, true)
 	elseif string.find(n.name, "mcl_farming:pumpkin_") then
-		bone_meal_particle(pos)
+		mcl_dye.add_bone_meal_particle(pos)
 		local stages = math.random(2, 5)
 		return mcl_farming:grow_plant("plant_pumpkin_stem", pos, n, stages, true)
 	elseif string.find(n.name, "mcl_farming:melontige_") then
-		bone_meal_particle(pos)
+		mcl_dye.add_bone_meal_particle(pos)
 		local stages = math.random(2, 5)
 		return mcl_farming:grow_plant("plant_melon_stem", pos, n, stages, true)
 	elseif string.find(n.name, "mcl_farming:beetroot_") then
-		bone_meal_particle(pos)
+		mcl_dye.add_bone_meal_particle(pos)
 		-- Beetroot: 75% chance to advance to next stage
 		if math.random(1, 100) <= 75 then
 			return mcl_farming:grow_plant("plant_beetroot", pos, n, 1, true)
 		end
 	elseif n.name == "mcl_cocoas:cocoa_1" or n.name == "mcl_cocoas:cocoa_2" then
-		bone_meal_particle(pos)
+		mcl_dye.add_bone_meal_particle(pos)
 		-- Cocoa: Advance by 1 stage
 		mcl_cocoas.grow(pos)
 		return true
 	elseif minetest.get_item_group(n.name, "grass_block") == 1 then
-		local grass_block_pos = {x = pos.x, y = pos.y + 1, z = pos.z}
-		bone_meal_particle(grass_block_pos)
 		-- Grass Block: Generate tall grass and random flowers all over the place
 		for i = -2, 2 do
 			for j = -2, 2 do
@@ -285,6 +299,7 @@ function mcl_dye.apply_bone_meal(pointed_thing)
 					-- Randomly generate flowers, tall grass or nothing
 					if math.random(1,100) <= 90 then
 						-- 90% tall grass, 10% flower
+						mcl_dye.add_bone_meal_particle(pos, {amount = 4})
 						if math.random(1,100) <= 90 then
 							local col = n2.param2
 							minetest.add_node(pos, {name="mcl_flowers:tallgrass", param2=col})
@@ -314,24 +329,24 @@ function mcl_dye.apply_bone_meal(pointed_thing)
 
 	-- Double flowers: Drop corresponding item
 	elseif n.name == "mcl_flowers:rose_bush" or n.name == "mcl_flowers:rose_bush_top" then
-		bone_meal_particle(pos)
+		mcl_dye.add_bone_meal_particle(pos)
 		minetest.add_item(pos, "mcl_flowers:rose_bush")
 		return true
 	elseif n.name == "mcl_flowers:peony" or n.name == "mcl_flowers:peony_top" then
-		bone_meal_particle(pos)
+		mcl_dye.add_bone_meal_particle(pos)
 		minetest.add_item(pos, "mcl_flowers:peony")
 		return true
 	elseif n.name == "mcl_flowers:lilac" or n.name == "mcl_flowers:lilac_top" then
-		bone_meal_particle(pos)
+		mcl_dye.add_bone_meal_particle(pos)
 		minetest.add_item(pos, "mcl_flowers:lilac")
 		return true
 	elseif n.name == "mcl_flowers:sunflower" or n.name == "mcl_flowers:sunflower_top" then
-		bone_meal_particle(pos)
+		mcl_dye.add_bone_meal_particle(pos)
 		minetest.add_item(pos, "mcl_flowers:sunflower")
 		return true
 
 	elseif n.name == "mcl_flowers:tallgrass" then
-		bone_meal_particle(pos)
+		mcl_dye.add_bone_meal_particle(pos)
 		-- Tall Grass: Grow into double tallgrass
 		local toppos = { x=pos.x, y=pos.y+1, z=pos.z }
 		local topnode = minetest.get_node(toppos)
@@ -342,7 +357,7 @@ function mcl_dye.apply_bone_meal(pointed_thing)
 		end
 
 	elseif n.name == "mcl_flowers:fern" then
-		bone_meal_particle(pos)
+		mcl_dye.add_bone_meal_particle(pos)
 		-- Fern: Grow into large fern
 		local toppos = { x=pos.x, y=pos.y+1, z=pos.z }
 		local topnode = minetest.get_node(toppos)
@@ -374,7 +389,7 @@ minetest.register_craftitem("mcl_dye:white", {
 		end
 
 		-- Use the bone meal on the ground
-		if(mcl_dye.apply_bone_meal(pointed_thing) and (not minetest.is_creative_enabled(user:get_player_name()))) then
+		if (apply_bone_meal(pointed_thing, user) and (not minetest.is_creative_enabled(user:get_player_name()))) then
 			itemstack:take_item()
 		end
 		return itemstack
@@ -387,7 +402,7 @@ minetest.register_craftitem("mcl_dye:white", {
 		else
 			pointed_thing = { above = pos, under = droppos }
 		end
-		local success = mcl_dye.apply_bone_meal(pointed_thing)
+		local success = apply_bone_meal(pointed_thing, nil)
 		if success then
 			stack:take_item()
 		end

mods/ITEMS/mcl_enchanting/init.lua

@@ -183,7 +183,7 @@ minetest.register_entity("mcl_enchanting:book", {
 		collisionbox = {0, 0, 0},
 		pointable = false,
 		physical = false,
-		textures = {"mcl_enchanting_book_entity.png"},
+		textures = {"mcl_enchanting_book_entity.png", "mcl_enchanting_book_entity.png", "mcl_enchanting_book_entity.png", "mcl_enchanting_book_entity.png", "mcl_enchanting_book_entity.png"},
 		static_save = false,
 	},
 	_player_near = false,

mods/MAPGEN/mcl_biomes/init.lua

@@ -1496,7 +1496,7 @@ local function register_dimension_biomes()
 		heat_point = 100,
 		humidity_point = 0,
 		_mcl_biome_type = "hot",
-		_mcl_palette_index = 19,
+		_mcl_palette_index = 17,
 	})
 
 	--[[ THE END ]]

tools/Texture_Converter.py

@@ -118,17 +118,6 @@ def colorize_alpha(colormap, source, colormap_pixel, texture_size, destination):
 	colorize(colormap, source, colormap_pixel, texture_size, tempfile2.name)
 	os.system("composite -compose Dst_In "+source+" "+tempfile2.name+" -alpha Set "+destination)
 
-# This function is unused atm.
-# TODO: Implemnt colormap extraction
-def extract_colormap(colormap, colormap_pixel, positions):
-	os.system("convert -size 16x16 canvas:black "+tempfile1.name)
-	x=0
-	y=0
-	for p in positions:
-		os.system("convert "+colormap+" -crop 1x1+"+colormap_pixel+" -depth 8 "+tempfile2.name)
-		os.system("composite -geometry 16x16+"+x+"+"+y+" "+tempfile2.name)
-		x = x+1
-
 def target_dir(directory):
 	if make_texture_pack:
 		return output_dir + "/" + output_dir_name
@@ -397,20 +386,60 @@ def convert_textures():
 		colorize_alpha(FOLIAG, tex_dir+"/blocks/vine.png", "16+39", str(PXSIZE), target_dir("/mods/ITEMS/mcl_core/textures")+"/mcl_core_vine.png")
 
 		# Tall grass, fern (inventory images)
-		pcol = "49+172" # Plains grass color
+		pcol = "50+173" # Plains grass color
 		colorize_alpha(GRASS, tex_dir+"/blocks/tallgrass.png", pcol, str(PXSIZE), target_dir("/mods/ITEMS/mcl_flowers/textures")+"/mcl_flowers_tallgrass_inv.png")
 		colorize_alpha(GRASS, tex_dir+"/blocks/fern.png", pcol, str(PXSIZE), target_dir("/mods/ITEMS/mcl_flowers/textures")+"/mcl_flowers_fern_inv.png")
 		colorize_alpha(GRASS, tex_dir+"/blocks/double_plant_fern_top.png", pcol, str(PXSIZE), target_dir("/mods/ITEMS/mcl_flowers/textures")+"/mcl_flowers_double_plant_fern_inv.png")
 		colorize_alpha(GRASS, tex_dir+"/blocks/double_plant_grass_top.png", pcol, str(PXSIZE), target_dir("/mods/ITEMS/mcl_flowers/textures")+"/mcl_flowers_double_plant_grass_inv.png")
 
-		# TODO: Convert grass palette
-
-		offset = [
-			[ pcol, "", "grass" ], # Default grass: Plains
+		# Convert grass palette: https://minecraft.fandom.com/wiki/Tint
+		grass_colors = [
+			# [Coords or #Color, AdditionalTint], # Index - Minecraft biome name (MineClone2 biome names)
+			["50+173"], # 0 - Plains (flat, Plains, Plains_beach, Plains_ocean, End)
+			["0+255"], # 1 - Savanna (Savanna, Savanna_beach, Savanna_ocean)
+			["255+255"], # 2 - Ice Spikes (IcePlainsSpikes, IcePlainsSpikes_ocean)
+			["255+255"], # 3 - Snowy Taiga (ColdTaiga, ColdTaiga_beach, ColdTaiga_beach_water, ColdTaiga_ocean)
+			["178+193"], # 4 - Giant Tree Taiga (MegaTaiga, MegaTaiga_ocean)
+			["178+193"], # 5 - Giant Tree Taiga (MegaSpruceTaiga, MegaSpruceTaiga_ocean)
+			["203+239"], # 6 - Montains (ExtremeHills, ExtremeHills_beach, ExtremeHills_ocean)
+			["203+239"], # 7 - Montains (ExtremeHillsM, ExtremeHillsM_ocean)
+			["203+239"], # 8 - Montains (ExtremeHills+, ExtremeHills+_snowtop, ExtremeHills+_ocean)
+			["50+173"], # 9 - Beach (StoneBeach, StoneBeach_ocean)
+			["255+255"], # 10 - Snowy Tundra (IcePlains, IcePlains_ocean)
+			["50+173"], # 11 - Sunflower Plains (SunflowerPlains, SunflowerPlains_ocean)
+			["191+203"], # 12 - Taiga (Taiga, Taiga_beach, Taiga_ocean)
+			["76+112"], # 13 - Forest (Forest, Forest_beach, Forest_ocean)
+			["76+112"], # 14 - Flower Forest (FlowerForest, FlowerForest_beach, FlowerForest_ocean)
+			["101+163"], # 15 - Birch Forest (BirchForest, BirchForest_ocean)
+			["101+163"], # 16 - Birch Forest Hills (BirchForestM, BirchForestM_ocean)
+			["0+255"], # 17 - Desert and Nether (Desert, Desert_ocean, Nether)
+			["76+112", "#28340A"], # 18 - Dark Forest (RoofedForest, RoofedForest_ocean)
+			["#90814d"], # 19 - Mesa (Mesa, Mesa_sandlevel, Mesa_ocean, )
+			["#90814d"], # 20 - Mesa (MesaBryce, MesaBryce_sandlevel, MesaBryce_ocean)
+			["#90814d"], # 21 - Mesa (MesaPlateauF, MesaPlateauF_grasstop, MesaPlateauF_sandlevel, MesaPlateauF_ocean)
+			["#90814d"], # 22 - Mesa (MesaPlateauFM, MesaPlateauFM_grasstop, MesaPlateauFM_sandlevel, MesaPlateauFM_ocean)
+			["0+255"], # 23 - Shattered Savanna (or Savanna Plateau ?) (SavannaM, SavannaM_ocean)
+			["12+36"], # 24 - Jungle (Jungle, Jungle_shore, Jungle_ocean)
+			["12+36"], # 25 - Modified Jungle (JungleM, JungleM_shore, JungleM_ocean)
+			["12+61"], # 26 - Jungle Edge (JungleEdge, JungleEdge_ocean)
+			["12+61"], # 27 - Modified Jungle Edge (JungleEdgeM, JungleEdgeM_ocean)
+			["#6A7039"], # 28 - Swamp (Swampland, Swampland_shore, Swampland_ocean)
+			["25+25"], # 29 - Mushroom Fields and Mushroom Field Shore (MushroomIsland, MushroomIslandShore, MushroomIsland_ocean)
 		]
-		for o in offset:
-			colorize(GRASS, tex_dir+"/blocks/grass_top.png", o[0], str(PXSIZE), target_dir("/mods/ITEMS/mcl_core/textures")+"/default_"+o[2]+".png")
-			colorize_alpha(GRASS, tex_dir+"/blocks/grass_side_overlay.png", o[0], str(PXSIZE), target_dir("/mods/ITEMS/mcl_core/textures")+"/default_"+o[2]+"_side.png")
+
+		grass_palette_file = target_dir("/mods/ITEMS/mcl_core/textures") + "/mcl_core_palette_grass.png"
+		os.system("convert -size 16x16 canvas:transparent " + grass_palette_file)
+
+		for i, color in enumerate(grass_colors):
+			if color[0][0] == "#":
+				os.system("convert -size 1x1 xc:\"" + color[0] + "\" " + tempfile1.name + ".png")
+			else:
+				os.system("convert " + GRASS + " -crop 1x1+" + color[0] + " " + tempfile1.name + ".png")
+
+			if len(color) > 1:
+				os.system("convert " + tempfile1.name + ".png \\( -size 1x1 xc:\"" + color[1] + "\" \\) -compose blend -define compose:args=50,50 -composite " + tempfile1.name + ".png")
+
+			os.system("convert " + grass_palette_file + " \\( " + tempfile1.name + ".png -geometry +" + str(i % 16) + "+" + str(int(i / 16)) + " \\) -composite " + grass_palette_file)
 
 		# Metadata
 		if make_texture_pack:

tools/generate_ingame_credits.lua

@@ -13,6 +13,7 @@ local colors = {
 	["3D Models"] = "0x0019FF",
 	["Textures"] = "0xFF9705",
 	["Translations"] = "0x00FF60",
+	["Funders"] = "0xF7FF00",
 	["Special thanks"] = "0x00E9FF",
 }