wip: allow bg/fg with ctermfg and ctermbg

Slightly modified solution that allows bg, fg, background, foreground to
be used as ctermfg and ctermbg colors, but also handles specific errors
if these are used when the foreground or background colors are unknown.

Note: has('gui') is still necessary as the terminal foreground and
background will never be known while the gui is running.

Author: mmrwoods

autoload/fuzzyy/utils/popup.vim

@@ -68,22 +68,18 @@ def ResolveCursor()
         hlset([fallback])
         return
     endif
-    var special = ['bg', 'fg', 'background', 'foreground']
+    var special = ['NONE', 'bg', 'fg', 'background', 'foreground']
     var guifg = attrs->get('guifg', 'NONE')
     var guibg = attrs->get('guibg', 'NONE')
     if has('gui')
         hlset([{name: 'fuzzyyCursor', guifg: guifg, guibg: guibg}])
         return
     endif
-    if index(special, guifg) != -1 || index(special, guibg) != -1
-        hlset([fallback])
-        return
-    endif
     var ctermfg = attrs->get('ctermfg',
-        guifg ==# 'NONE' ? 'NONE' : string(colors.TermColor(guifg))
+        index(special, guifg) != -1 ? guifg : string(colors.TermColor(guifg))
     )
     var ctermbg = attrs->get('ctermbg',
-        guibg ==# 'NONE' ? 'NONE' : string(colors.TermColor(guibg))
+        index(special, guibg) != -1 ? guibg : string(colors.TermColor(guibg))
     )
     try
         hlset([{
@@ -93,6 +89,9 @@ def ResolveCursor()
             ctermfg: ctermfg,
             ctermbg: ctermbg
         }])
+    catch /(E419|E420|E453)/
+        # foreground and/or background not known and used as ctermfg or ctermbg
+        hlset([fallback])
     catch
         Warn('Fuzzyy: failed to resolve cursor highlight: ' .. v:exception)
         hlset([fallback])