feat: teach match_listing.icons to accept a function

For future-proofing and flexibility.

Author: wincent

doc/command-t.txt

@@ -631,16 +631,27 @@ Possible vaules are:
     require('wincent.commandt').setup({ traverse = 'file' })
 
                                            *commandt.setup.match_listing.icons*
-                                                      boolean (default: true)
+                                          boolean or function (default: true)
 
-Controls whether to show icons in the match listing window (only for file-like
-results, not for things like |:CommandTHelp| results and other non-file
-entities).
+Controls whether (and how) to show icons in the match listing window (only
+for file-based results, not for things like |:CommandTHelp| results and other
+non-file entities).
 
-Requires the mini.icons plug-in.
+Using the default implementation (`true`) requires the mini.icons plug-in:
 
 - https://github.com/echasnovski/mini.icons
 
+Alternatively you can pass a function that takes a file path and returns an
+icon glyph. For example, here is a function that uses |MiniIcons.get()|:
+
+    require('wincent.commandt').setup({
+      match_listing = {
+        icons = function (name)
+          return _G.MiniIcons.get('file', name)
+        end,
+      },
+    })
+
                                         *commandt.setup.match_listing.truncate*
                                                    string (default: 'middle')
 

lua/wincent/commandt/init.lua

@@ -143,7 +143,12 @@ local options_spec = {
           },
         },
         icons = {
-          kind = 'boolean',
+          kind = {
+            one_of = {
+              { kind = 'boolean' },
+              { kind = 'function' },
+            },
+          },
         },
         truncate = {
           kind = {

lua/wincent/commandt/private/match_listing.lua

@@ -50,18 +50,22 @@ function MatchListing:close()
 end
 
 function MatchListing:icon_getter()
-  if self._icons and _G.MiniIcons then
+  if self._icons == true and _G.MiniIcons then
     return function(name)
       return _G.MiniIcons.get('file', name)
     end
+  elseif type(self._icons) == 'function' then
+    return self._icons
   end
 end
 
 local format_line = function(line, width, selected, truncate, get_icon)
   local prefix = selected and '> ' or '  '
 
   local icon = get_icon and get_icon(line)
+  local icon_length = 0
   if icon then
+    icon_length = #(icon .. '  ')
     prefix = prefix .. icon .. '  '
   end
 
@@ -77,7 +81,7 @@ local format_line = function(line, width, selected, truncate, get_icon)
 
   if #line + #prefix < width then
     -- Line fits without trimming.
-  elseif #line < (get_icon and 8 or 5) then
+  elseif #line < (5 + icon_length) then
     -- Line is so short that adding an ellipsis is not practical.
   elseif truncate == true or truncate == 'true' or truncate == 'middle' then
     local half = math.floor((width - 2) / 2)