Improve performance and fix index_event parsing

README.md

@@ -47,6 +47,10 @@ all attributes are lowercase.
 While I try to reduce backwards incompatibilities, sometimes they are necessary
 to either fix bugs in formspec_ast or for implementing new formspec features.
 
+#### March 2021
+
+ - The `index_event` value for `dropdown` is now a boolean instead of a string.
+
 #### February 2021
 
  - The `close_on_enter` value for `field_close_on_enter` is now a boolean

core.lua

@@ -401,22 +401,34 @@ end
 local compare_blanks
 do
     local function get_nonempty(a)
-        local nonempty = 0
+        if a.nonempty then
+            return a.nonempty, a.strings
+        end
+        local nonempty, strings = 0, 0
         for _, i in ipairs(a) do
             if type(i) == 'string' and i ~= '' then
                 nonempty = nonempty + 1
+                strings = strings + 1
             elseif type(i) == 'table' then
                 nonempty = nonempty + get_nonempty(i)
             end
         end
-        a.nonempty = nonempty
-        return nonempty
+        a.nonempty, a.strings = nonempty, strings
+        return nonempty, strings
     end
 
     function compare_blanks(a, b)
-        local a_n, b_n = get_nonempty(a), get_nonempty(b)
+        local a_n, a_strings = get_nonempty(a)
+        local b_n, b_strings = get_nonempty(b)
         if a_n == b_n then
-            return #a < #b
+            local a_l = #a
+            local b_l = #b
+            if a_l == b_l then
+                -- Prefer elements with less tables
+                return a_strings > b_strings
+            else
+                return a_l < b_l
+            end
         end
         return a_n >= b_n
     end

elements.yaml

@@ -114,7 +114,7 @@ dropdown:
   - - - [item, string]
       - '...'
   - [selected_idx, number]
-  - [index_event, string]
+  - [index_event, boolean]
 - - - [x, number]
     - [y, number]
   - [w, number]
@@ -122,7 +122,7 @@ dropdown:
   - - - [item, string]
       - '...'
   - [selected_idx, number]
-  - [index_event, string]
+  - [index_event, boolean]
 - - - [x, number]
     - [y, number]
   - - [w, number]

make_elements.py

@@ -19,7 +19,7 @@ _known = _make_known(
             'frame_duration', 'frame_start'),
     boolean=('auto_clip', 'fixed_size', 'transparent', 'draw_border', 'bool',
              'noclip', 'drawborder', 'selected', 'force', 'close_on_enter',
-             'continuous', 'mouse_control'),
+             'continuous', 'mouse_control', 'index_event'),
     fullscreen=('fullscreen',),
     table=('param', 'opt', 'prop'),
     null=('',),

tests.lua

@@ -80,6 +80,7 @@ local fs = [[
     image[0,1;1,1;air.png]
     set_focus[name;true]
     dropdown[0,0;1;test;abc,def,ghi,jkl;2]
+    dropdown[0,0;1;test;abc,def,ghi,jkl;2;true]
     field_close_on_enter[my-field;false]
     bgcolor[blue]
     bgcolor[blue;true]
@@ -168,6 +169,16 @@ test_parse_unparse(fs, {
         item = {"abc", "def", "ghi", "jkl"},
         selected_idx = 2,
     },
+    {
+        type = "dropdown",
+        x = 0,
+        y = 0,
+        w = 1,
+        name = "test",
+        item = {"abc", "def", "ghi", "jkl"},
+        selected_idx = 2,
+        index_event = true,
+    },
     {
         type = "field_close_on_enter",
         name = "my-field",