Add snippets.Form.

core.lua

@@ -149,6 +149,12 @@ local function wrap(snippet, func)
     return function(...) return wrap_raw(snippet, func, ...) end
 end
 
+-- Expose the above function to the API.
+-- This will only wrap functions if called from inside a snippet.
+function snippets.wrap_callback(func)
+    return wrap(running_snippet, func)
+end
+
 do
     local after_ = minetest.after
     function safe_funcs.after(after, func, ...)

depends.txt

@@ -0,0 +1 @@
+cloaking?

forms.lua

@@ -0,0 +1,155 @@
+--
+-- Minetest snippets mod: A formspec API
+--
+-- This should probably be put in formspeclib.
+--
+
+local open_formspecs = {}
+
+minetest.register_on_leaveplayer(function(player)
+    local name = player:get_player_name()
+    open_formspecs[name] = nil
+end)
+
+local get_player_by_name = minetest.global_exists('cloaking') and
+    cloaking.get_player_by_name or minetest.get_player_by_name
+
+-- Formspec objects
+-- You can create one of these per player and handle input
+local Form = {}
+local forms = {}
+setmetatable(forms, {__mode = 'k'})
+local function get(form)
+    if not forms[form] then
+        error('snippets.Form method called on a non-Form!', 3)
+    end
+    return forms[form]
+end
+
+-- Get unique formnames
+local used_ids = {}
+setmetatable(used_ids, {__mode = 'v'})
+
+local function get_next_formname(form)
+    -- Iterate over it because of inconsistencies when getting the length of a
+    --  list containing nil.
+    local id = 1
+    for _ in ipairs(used_ids) do id = id + 1 end
+
+    -- ID should be equal to #used_ids + 1.
+    used_ids[id] = form
+    return 'snippets:form_' .. id
+end
+
+-- Override minetest.show_formspec
+local show_formspec = minetest.show_formspec
+function minetest.show_formspec(pname, ...)
+    if pname then open_formspecs[pname] = nil end
+    return show_formspec(pname, ...)
+end
+
+-- Show formspecs
+local print = print
+function Form:show()
+    local data = get(self)
+    if not get_player_by_name(data.victim) then return false end
+    open_formspecs[data.victim] = self
+    print('show_formspec', data.victim, data.formname,
+        data.prepend .. data.formspec .. data.append)
+    show_formspec(data.victim, data.formname,
+        data.prepend .. data.formspec .. data.append)
+    return true
+end
+Form.open = Form.show
+
+-- Close formspecs
+function Form:close()
+    local data = get(self)
+    if open_formspecs[data.victim] == self then
+        minetest.close_formspec(data.victim, data.name)
+        open_formspecs[data.victim] = nil
+    end
+end
+Form.hide = Form.close
+
+-- Prepends etc
+function Form:get_prepend()  return get(self).prepend  end
+function Form:get_formspec() return get(self).formspec end
+function Form:get_append()   return get(self).append   end
+
+function Form:set_prepend(text)
+    local data = get(self)
+    data.prepend = tostring(text or '')
+    if open_formspecs[data.victim] == self then self:show() end
+end
+
+function Form:set_formspec(text)
+    local data = get(self)
+    data.formspec = tostring(text or '')
+    if open_formspecs[data.victim] == self then self:show() end
+end
+
+function Form:set_append(text)
+    local data = get(self)
+    data.append = tostring(text or '')
+    if open_formspecs[data.victim] == self then self:show() end
+end
+
+-- Callbacks
+function Form:add_callback(...)
+    local data, argc = get(self), select('#', ...)
+    local event, func
+    if argc == 1 then
+        event, func = '', ...
+    elseif argc == 2 then
+        event, func = ...
+        if type(event) ~= 'string' then
+            error('Invalid usage for snippets.Form:add_callback().', 2)
+        end
+    else
+        error('snippets.Form:add_callback() takes one or two arguments.', 2)
+    end
+
+    if not data.callbacks[event] then data.callbacks[event] = {} end
+    table.insert(data.callbacks[event], snippets.wrap_callback(func))
+end
+
+-- Create a Formspec object
+function snippets.Form(player)
+    if minetest.is_player(player) then player = player:get_player_name() end
+    if type(player) ~= 'string' or not get_player_by_name(player) then
+        error('Attempted to create a Form for a non-existent player!', 2)
+    end
+    local form = {context = {}}
+    setmetatable(form, {__index = Form})
+    forms[form] = {
+        victim = player, prepend = '', formspec = '', append = '',
+        callbacks = {}, formname = get_next_formname(form), pname = player,
+    }
+    return form
+end
+
+-- Callbacks
+local function run_callbacks(callbacks, ...)
+    if not callbacks then return end
+    for _, func in ipairs(callbacks) do func(...) end
+end
+
+minetest.register_on_player_receive_fields(function(player, formname, fields)
+    if formname:sub(1, 14) ~= 'snippets:form_' then return end
+    local pname = player:get_player_name()
+    local form = open_formspecs[pname]
+    local data = forms[form]
+    if not data or data.formname ~= formname then return end
+
+    -- Nuke the formspec if required
+    if fields.quit then open_formspecs[pname] = nil end
+
+    -- Run generic callbacks
+    run_callbacks(data.callbacks[''], form, fields)
+
+    -- Run field-specific callbacks
+    for k, v in pairs(fields) do
+        run_callbacks(data.callbacks[k], form, fields)
+    end
+end)

init.lua

@@ -13,6 +13,9 @@ dofile(modpath .. '/core.lua')
 -- Load persistence
 loadfile(modpath .. '/persistence.lua')(minetest.get_mod_storage())
 
+-- Load the Form object
+dofile(modpath .. '/forms.lua')
+
 -- Load the "console"
 dofile(modpath .. '/console.lua')
 

mod.conf

@@ -0,0 +1,2 @@
+name = snippets
+optional_depends = cloaking