Merge pull request #17589 from kchibisov/add-dashed-dotted-underline

Add support for double, dashed, and dotted underlines 

4 files changed, 46 insertions, 30 deletions

diff --git a/runtime/doc/builtin.txt b/runtime/doc/builtin.txt
index 03a5f98c6d..b0859d1cea 100644
--- a/runtime/doc/builtin.txt
+++ b/runtime/doc/builtin.txt
@@ -7937,8 +7937,11 @@ synIDattr({synID}, {what} [, {mode}])			*synIDattr()*
 		"inverse"	"1" if inverse (= reverse)
 		"standout"	"1" if standout
 		"underline"	"1" if underlined
+		"underlineline"	"1" if double underlined
 		"undercurl"	"1" if undercurled
-		"strikethrough"	"1" if struckthrough
+		"underdot"	"1" if dotted underlined
+		"underdash"	"1" if dashed underlined
+		"strikethrough" "1" if struckthrough
 
 		Example (echoes the color of the syntax item under the
 		cursor): >
diff --git a/runtime/doc/syntax.txt b/runtime/doc/syntax.txt
index 778f829a4e..9084c5315a 100644
--- a/runtime/doc/syntax.txt
+++ b/runtime/doc/syntax.txt
@@ -4875,7 +4875,8 @@ the same syntax file on all UIs.
 
 1. TUI highlight arguments
 
-					*bold* *underline* *undercurl*
+					*bold* *underline* *underlineline*
+					*undercurl* *underdot* *underdash*
 					*inverse* *italic* *standout*
 					*nocombine* *strikethrough*
 cterm={attr-list}			*attr-list* *highlight-cterm* *E418*
@@ -4883,7 +4884,10 @@ cterm={attr-list}			*attr-list* *highlight-cterm* *E418*
 	following items (in any order):
 		bold
 		underline
+		underlineline	double underline
 		undercurl	curly underline
+		underdot	dotted underline
+		underdash	dashed underline
 		strikethrough
 		reverse
 		inverse		same as reverse
@@ -4894,8 +4898,9 @@ cterm={attr-list}			*attr-list* *highlight-cterm* *E418*
 
 	Note that "bold" can be used here and by using a bold font.  They
 	have the same effect.
-	"undercurl" falls back to "underline" in a terminal that does not
-	support it.  The color is set using |highlight-guisp|.
+	"underlineline", "undercurl", "underdot", and "underdash" fall back
+	to "underline" in a terminal that does not support them. The color is
+	set using |highlight-guisp|.
 
 start={term-list}				*highlight-start* *E422*
 stop={term-list}				*term-list* *highlight-stop*
@@ -5028,8 +5033,8 @@ guifg={color-name}					*highlight-guifg*
 guibg={color-name}					*highlight-guibg*
 guisp={color-name}					*highlight-guisp*
 	These give the foreground (guifg), background (guibg) and special
-	(guisp) color to use in the GUI.  "guisp" is used for undercurl
-	and underline.
+	(guisp) color to use in the GUI.  "guisp" is used for various
+	underlines.
 	There are a few special names:
 		NONE		no color (transparent)
 		bg		use normal background color
diff --git a/runtime/doc/ui.txt b/runtime/doc/ui.txt
index e7be14e732..c5e3b60079 100644
--- a/runtime/doc/ui.txt
+++ b/runtime/doc/ui.txt
@@ -283,19 +283,24 @@ numerical highlight ids to the actual attributes.
 	attributes specified by the `rgb_attr` and `cterm_attr` dicts, with the
 	following (all optional) keys.
 
-	`foreground`:	foreground color.
-	`background`:	background color.
-	`special`:	color to use for underline and undercurl, when present.
-	`reverse`:	reverse video. Foreground and background colors are
-			switched.
-	`italic`:	italic text.
-	`bold`:		bold text.
-	`strikethrough`:  struckthrough text.
-	`underline`:	underlined text. The line has `special` color.
-	`undercurl`:	undercurled text. The curl has `special` color.
-	`blend`:	Blend level (0-100). Could be used by UIs to support
-			blending floating windows to the background or to
-			signal a transparent cursor.
+	`foreground`:		foreground color.
+	`background`:		background color.
+	`special`:		color to use for various underlines, when
+				present.
+	`reverse`:		reverse video. Foreground and background colors
+				are switched.
+	`italic`:		italic text.
+	`bold`:			bold text.
+	`strikethrough`:	struckthrough text.
+	`underline`:		underlined text. The line has `special` color.
+	`underlineline`:	double underlined text. The lines have `special`
+				color.
+	`undercurl`:		undercurled text. The curl has `special` color.
+	`underdot`:		underdotted text. The dots have `special` color.
+	`underdash`:		underdashed text. The dashes have `special` color.
+	`blend`:		Blend level (0-100). Could be used by UIs to
+				support blending floating windows to the
+				background or to signal a transparent cursor.
 
 	For absent color keys the default color should be used. Don't store
 	the default value in the table, rather a sentinel value, so that
@@ -444,14 +449,17 @@ is not active. New UIs should implement |ui-linegrid| instead.
 
 	`foreground`:	foreground color.
 	`background`:	background color.
-	`special`:	color to use for underline and undercurl, when present.
+	`special`:	color to use for various underlines, when present.
 	`reverse`:	reverse video. Foreground and background colors are
 			switched.
 	`italic`:	italic text.
 	`bold`:		bold text.
 	`strikethrough`:  struckthrough text.
 	`underline`:	underlined text. The line has `special` color.
+	`underlineline`:  double underlined text. The lines have `special` color.
 	`undercurl`:	undercurled text. The curl has `special` color.
+	`underdot`:	underdotted text. The dots have `special` color.
+	`underdash`:	underdashed text. The dashes have `special` color.
 
 ["put", text]
 	The (utf-8 encoded) string `text` is put at the cursor position
diff --git a/runtime/syntax/vim.vim b/runtime/syntax/vim.vim
index 41993b65b0..0bc233fc2a 100644
--- a/runtime/syntax/vim.vim
+++ b/runtime/syntax/vim.vim
@@ -46,14 +46,14 @@ syn match   vimTermOption contained	"t_%i"
 syn match   vimTermOption contained	"t_k;"
 
 " unsupported settings: these are supported by vi but don't do anything in vim {{{2
-syn keyword vimErrSetting contained	hardtabs ht w1200 w300 w9600 
+syn keyword vimErrSetting contained	hardtabs ht w1200 w300 w9600
 "}}}2
 syn case ignore
 " Highlight commonly used Groupnames {{{2
-syn keyword vimGroup contained	Comment Constant String Character Number Boolean Float Identifier Function Statement Conditional Repeat Label Operator Keyword Exception PreProc Include Define Macro PreCondit Type StorageClass Structure Typedef Special SpecialChar Tag Delimiter SpecialComment Debug Underlined Ignore Error Todo 
+syn keyword vimGroup contained	Comment Constant String Character Number Boolean Float Identifier Function Statement Conditional Repeat Label Operator Keyword Exception PreProc Include Define Macro PreCondit Type StorageClass Structure Typedef Special SpecialChar Tag Delimiter SpecialComment Debug Underlined Ignore Error Todo
 
 " Default highlighting groups {{{2
-syn keyword vimHLGroup contained	ColorColumn Cursor CursorColumn CursorIM CursorLine CursorLineFold CursorLineNr CursorLineSign DiffAdd DiffChange DiffDelete DiffText Directory EndOfBuffer ErrorMsg FoldColumn Folded IncSearch LineNr MatchParen Menu ModeMsg MoreMsg NonText Normal Pmenu PmenuSbar PmenuSel PmenuThumb Question QuickFixLine Scrollbar Search SignColumn SpecialKey SpellBad SpellCap SpellLocal SpellRare StatusLine StatusLineNC TabLine TabLineFill TabLineSel Title Tooltip VertSplit Visual WarningMsg WildMenu 
+syn keyword vimHLGroup contained	ColorColumn Cursor CursorColumn CursorIM CursorLine CursorLineFold CursorLineNr CursorLineSign DiffAdd DiffChange DiffDelete DiffText Directory EndOfBuffer ErrorMsg FoldColumn Folded IncSearch LineNr MatchParen Menu ModeMsg MoreMsg NonText Normal Pmenu PmenuSbar PmenuSel PmenuThumb Question QuickFixLine Scrollbar Search SignColumn SpecialKey SpellBad SpellCap SpellLocal SpellRare StatusLine StatusLineNC TabLine TabLineFill TabLineSel Title Tooltip VertSplit Visual WarningMsg WildMenu
 syn match vimHLGroup contained	"Conceal"
 syn keyword vimOnlyHLGroup contained	LineNrAbove LineNrBelow StatusLineTerm Terminal VisualNOS
 syn keyword nvimHLGroup contained	Substitute TermCursor TermCursorNC
@@ -88,10 +88,10 @@ if exists("g:vimsyn_folding") && g:vimsyn_folding =~# '[afhlmpPrt]'
  else
   com! -nargs=* VimFoldm <args>
  endif
- if g:vimsyn_folding =~# 'p' 
-  com! -nargs=* VimFoldp <args> fold 
- else 
-  com! -nargs=* VimFoldp <args> 
+ if g:vimsyn_folding =~# 'p'
+  com! -nargs=* VimFoldp <args> fold
+ else
+  com! -nargs=* VimFoldp <args>
  endif
  if g:vimsyn_folding =~# 'P'
   com! -nargs=* VimFoldP <args> fold
@@ -148,8 +148,8 @@ syn match vimNumber	'-\d\+\%(\.\d\+\%([eE][+-]\=\d\+\)\=\)\='  skipwhite nextgro
 syn match vimNumber	'\<0[xX]\x\+'		       skipwhite nextgroup=vimGlobal,vimSubst,vimCommand,vimComment,vim9Comment
 syn match vimNumber	'\%(^\|\A\)\zs#\x\{6}'             	       skipwhite nextgroup=vimGlobal,vimSubst,vimCommand,vimComment,vim9Comment
 syn match vimNumber	'\<0[zZ][a-zA-Z0-9.]\+'                    skipwhite nextgroup=vimGlobal,vimSubst,vimCommand,vimComment,vim9Comment
-syn match vimNumber	'0[0-7]\+'		       skipwhite nextgroup=vimGlobal,vimSubst,vimCommand,vimComment,vim9Comment           
-syn match vimNumber	'0[bB][01]\+'		       skipwhite nextgroup=vimGlobal,vimSubst,vimCommand,vimComment,vim9Comment           
+syn match vimNumber	'0[0-7]\+'		       skipwhite nextgroup=vimGlobal,vimSubst,vimCommand,vimComment,vim9Comment
+syn match vimNumber	'0[bB][01]\+'		       skipwhite nextgroup=vimGlobal,vimSubst,vimCommand,vimComment,vim9Comment
 
 " All vimCommands are contained by vimIsCommand. {{{2
 syn match vimCmdSep	"[:|]\+"	skipwhite nextgroup=vimAddress,vimAutoCmd,vimEcho,vimIsCommand,vimExtCmd,vimFilter,vimLet,vimMap,vimMark,vimSet,vimSyntax,vimUserCmd
@@ -574,7 +574,7 @@ syn match	vimHiBang	contained	"!"	skipwhite nextgroup=@vimHighlightCluster
 
 syn match	vimHiGroup	contained	"\i\+"
 syn case ignore
-syn keyword	vimHiAttrib	contained	none bold inverse italic nocombine reverse standout strikethrough underline undercurl
+syn keyword	vimHiAttrib	contained	none bold inverse italic nocombine reverse standout strikethrough underline underlineline undercurl underdot underdash
 syn keyword	vimFgBgAttrib	contained	none bg background fg foreground
 syn case match
 syn match	vimHiAttribList	contained	"\i\+"	contains=vimHiAttrib