Add code folding event.

core/events.lua

@@ -170,6 +170,12 @@ local M = {}
 -- This event is never emitted when Textadept is running in the terminal.
 -- @field FOCUS
 
+--- Emitted after code folding is done by the lexer.
+-- This is useful for performing manual folding and manipulation of the folding table 
+-- `buffer.fold_level` after lexer is done folding the code, where the built-in facilities for
+-- code folding doesn't suffice.
+-- @field FOLDED
+
 --- Emitted when clicking the mouse on text that has an indicator present.
 -- Arguments:
 --

core/lexer.lua

@@ -126,6 +126,7 @@ local function highlight(buffer, start_pos, end_pos)
 	local level = buffer.fold_level[line] & buffer.FOLDLEVELNUMBERMASK
 	local folds = buffer.lexer:fold(buffer:text_range(start_pos, end_pos), line, level)
 	for line, level in pairs(folds) do buffer.fold_level[line] = level end
+	events.emit(events.FOLDED)
 end
 
 local mutex

docs/api.md

@@ -4871,7 +4871,7 @@ shortly after this event.
 The buffer **must not** be modified during this event.
 
 <a id="events.BUFFER_BEFORE_SWITCH"></a>
-#### `events.BUFFER_BEFORE_SWITCH` 
+#### `events.BUFFER_BEFORE_SWITCH`
 
 Emitted right before switching to another buffer.
 The buffer being switched from is [`buffer`](#buffer).
@@ -5119,6 +5119,14 @@ Arguments:
 
 - *name*: The language lexer's name.
 
+<a id="events.FOLDED"></a>
+#### `events.FOLDED` 
+
+Emitted after code folding is done by the lexer.
+This is useful for performing manual folding and manipulation of the folding table 
+`buffer.fold_level` after lexer is done folding the code, where the built-in facilities for
+[code folding](#code-folding) doesn't suffice.
+
 <a id="events.MARGIN_CLICK"></a>
 #### `events.MARGIN_CLICK`