Make `ui.highlight_words` a multi-option setting.

Highlighting the current word could be useful instead of just the selected word.

1 files changed, 37 insertions, 19 deletions

diff --git a/core/ui.lua b/core/ui.lua
index ce7aeb84..7aa15070 100644
--- a/core/ui.lua
+++ b/core/ui.lua
@@ -33,16 +33,25 @@ local ui = ui
 --   with a group of [`ui.print()`]() and [`ui._print()`]() function calls.
 --   The default value is `false`, and focuses buffers when messages are printed
 --   to them.
--- @field highlight_words (bool)
---   Whether or not to automatically highlight all instances of the selected
---   word.
---   The default value is `true` except in the terminal version.
+-- @field highlight_words (number)
+--   The word highlight mode.
+--
+--   * `ui.HIGHLIGHT_CURRENT`
+--     Automatically highlight all instances of the current word.
+--   * `ui.HIGHLIGHT_SELECTED`
+--     Automatically highlight all instances of the selected word.
+--   * `ui.HIGHLIGHT_NONE`
+--     Do not automatically highlight words.
+--
+--   The default value is `ui.HIGHLIGHT_SELECTED` except in the terminal
+--   version, where it is `ui.HIGHLIGHT_NONE`.
 -- @field INDIC_HIGHLIGHT (number)
 --   The word highlight indicator number.
 module('ui')]]
 
 ui.silent_print = false
-ui.highlight_words = not CURSES
+ui.HIGHLIGHT_NONE, ui.HIGHLIGHT_CURRENT, ui.HIGHLIGHT_SELECTED = 1, 2, 3
+ui.highlight_words = not CURSES and ui.HIGHLIGHT_SELECTED or ui.HIGHLIGHT_NONE
 ui.INDIC_HIGHLIGHT = _SCINTILLA.next_indic_number()
 
 -- Helper function for printing messages to buffers.
@@ -300,21 +309,30 @@ events_connect(events.KEYPRESS, function(code)
   if keys.KEYSYMS[code] == 'esc' then clear_highlighted_words() end
 end, 1)
 
--- Highlight all instances of the selected word.
+-- Highlight all instances of the current or selected word.
 events_connect(events.UPDATE_UI, function(updated)
-  if updated and updated & buffer.UPDATE_SELECTION > 0 and
-     ui.highlight_words and not buffer.selection_empty and
-     buffer:is_range_word(buffer.selection_start, buffer.selection_end) and
-     buffer:get_sel_text():find('^%S+$') then
-    clear_highlighted_words()
-    local word = buffer:text_range(buffer.selection_start, buffer.selection_end)
-    buffer.search_flags = buffer.FIND_MATCHCASE | buffer.FIND_WHOLEWORD
-    buffer:target_whole_document()
-    while buffer:search_in_target(word) ~= -1 do
-      buffer:indicator_fill_range(
-        buffer.target_start, buffer.target_end - buffer.target_start)
-      buffer:set_target_range(buffer.target_end, buffer.length + 1)
-    end
+  if not updated or updated & buffer.UPDATE_SELECTION == 0 then return end
+  local word
+  if ui.highlight_words == ui.HIGHLIGHT_CURRENT then
+    local s = buffer:word_start_position(buffer.current_pos, true)
+    local e = buffer:word_end_position(buffer.current_pos, true)
+    if s == e then clear_highlighted_words() return end
+    word = buffer:text_range(s, e)
+  elseif ui.highlight_words == ui.HIGHLIGHT_SELECTED then
+    local s, e = buffer.selection_start, buffer.selection_end
+    if not buffer:is_range_word(s, e) then return end
+    word = buffer:get_sel_text()
+    if not word:find('^%S+$') then return end
+  else
+    return
+  end
+  clear_highlighted_words()
+  buffer.search_flags = buffer.FIND_MATCHCASE | buffer.FIND_WHOLEWORD
+  buffer:target_whole_document()
+  while buffer:search_in_target(word) ~= -1 do
+    buffer:indicator_fill_range(
+      buffer.target_start, buffer.target_end - buffer.target_start)
+    buffer:set_target_range(buffer.target_end, buffer.length + 1)
   end
 end)