vim-patch:9.1.0013: Modula2 filetype support lacking (#27020)

Problem:  Modula2 filetype support lacking
Solution: Improve the Modula-2 runtime support, add additional modula2
          dialects, add compiler plugin, update syntax highlighting,
          include syntax tests, update Makefiles (Doug Kearns)

closes: vim/vim#6796
closes: vim/vim#8115

https://github.com/vim/vim/commit/68a89470693c7687d4e736ca056c05de632e3ac7

- Luaify the detection script:

  - Split the `(*!m2foo*)` and `(*!m2foo+bar*)` detection into two Lua patterns,
    as Lua capture groups cannot be used with `?` and friends (as they only work
    on character classes).

  - Use `vim.api.nvim_buf_call()` (ew) to call `modula2#SetDialect()` to ensure
    `b:modula2` is set for the given bufnr.

- Skip the syntax screendump tests. (A shame as they test some of the detection
  from `(*!m2foo+bar*)` tags, but I tested this locally and it seems to work)

- Port the synmenu.vim changes from Vim9 script. (Also tested this locally)

- (And also add the missing comma for `b:browsefilter` from earlier.)

Co-authored-by: Doug Kearns <dougkearns@gmail.com>

14 files changed, 1468 insertions, 105 deletions

diff --git a/runtime/autoload/modula2.vim b/runtime/autoload/modula2.vim
new file mode 100644
index 0000000000..284dc2768f
--- /dev/null
+++ b/runtime/autoload/modula2.vim
@@ -0,0 +1,31 @@
+" Vim filetype plugin file
+" Language:	Modula-2
+" Maintainer:	Doug Kearns <dougkearns@gmail.com>
+" Last Change:	2024 Jan 04
+
+" Dialect can be one of pim, iso, r10
+function modula2#GetDialect() abort
+
+  if exists("b:modula2.dialect")
+    return b:modula2.dialect
+  endif
+
+  if exists("g:modula2_default_dialect")
+    let dialect = g:modula2_default_dialect
+  else
+    let dialect = "pim"
+  endif
+
+  return dialect
+endfunction
+
+function modula2#SetDialect(dialect, extension = "") abort
+  if exists("b:modula2")
+    unlockvar! b:modula2
+  endif
+
+  let b:modula2 = #{ dialect: a:dialect, extension: a:extension }
+  lockvar! b:modula2
+endfunction
+
+" vim: nowrap sw=2 sts=2 ts=8 noet fdm=marker:
diff --git a/runtime/compiler/gm2.vim b/runtime/compiler/gm2.vim
new file mode 100644
index 0000000000..5053912200
--- /dev/null
+++ b/runtime/compiler/gm2.vim
@@ -0,0 +1,26 @@
+" Vim compiler file
+" Compiler:	GNU Modula-2 Compiler
+" Maintainer:	Doug Kearns <dougkearns@gmail.com>
+" Last Change:	2024 Jan 04
+
+if exists("current_compiler")
+  finish
+endif
+let current_compiler = "gm2"
+
+if exists(":CompilerSet") != 2		" older Vim always used :setlocal
+  command -nargs=* CompilerSet setlocal <args>
+endif
+
+let s:cpo_save = &cpo
+set cpo&vim
+
+CompilerSet makeprg=gm2
+CompilerSet errorformat=%-G%f:%l:%c:\ error:\ compilation\ failed,
+		       \%f:%l:%c:\ %trror:\ %m,
+		       \%f:%l:%c:\ %tarning:\ %m,
+		       \%f:%l:%c:\ %tote:\ %m,
+		       \%-G%.%#
+
+let &cpo = s:cpo_save
+unlet s:cpo_save
diff --git a/runtime/doc/filetype.txt b/runtime/doc/filetype.txt
index 6c2cddea54..29b929b8a5 100644
--- a/runtime/doc/filetype.txt
+++ b/runtime/doc/filetype.txt
@@ -146,6 +146,7 @@ variables can be used to overrule the filetype used for certain extensions:
 	`*.cls`		g:filetype_cls
 	`*.csh`		g:filetype_csh		|ft-csh-syntax|
 	`*.dat`		g:filetype_dat
+	`*.def`		g:filetype_def
 	`*.f`		g:filetype_f		|ft-forth-syntax|
 	`*.frm`		g:filetype_frm		|ft-form-syntax|
 	`*.fs`		g:filetype_fs		|ft-forth-syntax|
diff --git a/runtime/doc/syntax.txt b/runtime/doc/syntax.txt
index 8cbb958e35..9164171152 100644
--- a/runtime/doc/syntax.txt
+++ b/runtime/doc/syntax.txt
@@ -2206,6 +2206,56 @@ have the following in your vimrc: >
 	let filetype_m = "mma"
 
 
+MODULA2					*modula2.vim* *ft-modula2-syntax*
+
+Vim will recognise comments with dialect tags to automatically select a given
+dialect.
+
+The syntax for a dialect tag comment is: >
+
+	taggedComment :=
+	  '(*!' dialectTag '*)'
+	  ;
+
+	dialectTag :=
+	  m2pim | m2iso | m2r10
+	  ;
+
+	reserved words
+	  m2pim = 'm2pim', m2iso = 'm2iso', m2r10 = 'm2r10'
+
+A dialect tag comment is recognised by Vim if it occurs within the first 200
+lines of the source file. Only the very first such comment is recognised, any
+additional dialect tag comments are ignored.
+
+Example: >
+
+	DEFINITION MODULE FooLib; (*!m2pim*)
+	...
+
+Variable g:modula2_default_dialect sets the default Modula-2 dialect when the
+dialect cannot be determined from the contents of the Modula-2 file: if
+defined and set to 'm2pim', the default dialect is PIM.
+
+Example: >
+
+	let g:modula2_default_dialect = 'm2pim'
+
+
+Highlighting is further configurable for each dialect via the following
+variables.
+
+Variable			Highlight ~
+*modula2_iso_allow_lowline*	allow low line in identifiers
+*modula2_iso_disallow_octals*	disallow octal integer literals
+*modula2_iso_disallow_synonyms*	disallow "@", "&" and "~" synonyms
+
+*modula2_pim_allow_lowline*	allow low line in identifiers
+*modula2_pim_disallow_octals*	disallow octal integer literals
+*modula2_pim_disallow_synonyms*	disallow "&" and "~" synonyms
+
+*modula2_r10_allow_lowline*	allow low line in identifiers
+
 MOO						*moo.vim* *ft-moo-syntax*
 
 If you use C-style comments inside expressions and find it mangles your
diff --git a/runtime/ftplugin/modula2.vim b/runtime/ftplugin/modula2.vim
index 8c4a876c0f..9c1acc276a 100644
--- a/runtime/ftplugin/modula2.vim
+++ b/runtime/ftplugin/modula2.vim
@@ -11,32 +11,43 @@ let b:did_ftplugin = 1
 let s:cpo_save = &cpo
 set cpo&vim
 
-setlocal comments=s0:(*,mb:\ ,ex:*)
-setlocal commentstring=(*%s*)
+let s:dialect = modula2#GetDialect()
+
+if s:dialect ==# "r10"
+  setlocal comments=s:(*,m:\ ,e:*),:!
+  setlocal commentstring=!\ %s
+else
+  setlocal commentstring=(*%s*)
+  setlocal comments=s:(*,m:\ ,e:*)
+endif
 setlocal formatoptions-=t formatoptions+=croql
 
+let b:undo_ftplugin = "setl com< cms< fo<"
+
 if exists("loaded_matchit") && !exists("b:match_words")
-  " The second branch of the middle pattern is intended to match CASE labels
+  let b:match_ignorecase = 0
+  " the second branch of the middle pattern is intended to match CASE labels
   let b:match_words = '\<REPEAT\>:\<UNTIL\>,' ..
-		    \ '\<\%(BEGIN\|CASE\|FOR\|IF\|LOOP\|WHILE\|WITH\)\>' ..
-		    \	':' ..
-		    \	'\<\%(ELSIF\|ELSE\)\>\|\%(^\s*\)\@<=\w\+\%(\s*\,\s*\w\+\)\=\s*\:=\@!' ..
-		    \	':' ..
-		    \ '\<END\>'
+	\	      '\<\%(BEGIN\|CASE\|FOR\|IF\|LOOP\|WHILE\|WITH\|RECORD\)\>' ..
+	\		':' ..
+	\		'\<\%(ELSIF\|ELSE\)\>\|\%(^\s*\)\@<=\w\+\%(\s*\,\s*\w\+\)\=\s*\:=\@!' ..
+	\		':' ..
+	\	      '\<END\>,' ..
+	\	      '(\*:\*),<\*:\*>'
+  let b:match_skip = 's:Comment\|Pragma'
+  let b:undo_ftplugin ..= " | unlet! b:match_ignorecase b:match_skip b:match_words"
 endif
 
 if (has("gui_win32") || has("gui_gtk")) && !exists("b:browsefilter")
-  let b:browsefilter = "Modula-2 Source Files (*.def *.mod)\t*.def;*.mod\n"
+  let b:browsefilter = "Modula-2 Source Files (*.def, *.mod)\t*.def;*.mod\n"
   if has("win32")
     let b:browsefilter ..= "All Files (*.*)\t*\n"
   else
     let b:browsefilter ..= "All Files (*)\t*\n"
   endif
+  let b:undo_ftplugin ..= " | unlet! b:browsefilter"
 endif
 
-let b:undo_ftplugin = "setl com< cms< fo< " ..
-		    \ "| unlet! b:browsefilter b:match_words"
-
 let &cpo = s:cpo_save
 unlet s:cpo_save
 
diff --git a/runtime/lua/vim/filetype.lua b/runtime/lua/vim/filetype.lua
index 8cd5f19569..a83c74fd7c 100644
--- a/runtime/lua/vim/filetype.lua
+++ b/runtime/lua/vim/filetype.lua
@@ -341,7 +341,7 @@ local extension = {
   decl = detect.decl,
   dec = detect.decl,
   dcl = detect_seq(detect.decl, 'clean'),
-  def = 'def',
+  def = detect.def,
   desc = 'desc',
   directory = 'desktop',
   desktop = 'desktop',
@@ -674,8 +674,6 @@ local extension = {
   mmp = 'mmp',
   mms = detect.mms,
   DEF = 'modula2',
-  m2 = 'modula2',
-  mi = 'modula2',
   lm3 = 'modula3',
   mojo = 'mojo',
   ['🔥'] = 'mojo', -- 🙄
diff --git a/runtime/lua/vim/filetype/detect.lua b/runtime/lua/vim/filetype/detect.lua
index 6a14c73c92..ce3b873e40 100644
--- a/runtime/lua/vim/filetype/detect.lua
+++ b/runtime/lua/vim/filetype/detect.lua
@@ -419,6 +419,55 @@ function M.dtrace(_, bufnr)
   return 'd'
 end
 
+--- @param bufnr integer
+--- @return boolean
+local function is_modula2(bufnr)
+  return matchregex(nextnonblank(bufnr, 1), [[\<MODULE\s\+\w\+\s*;\|^\s*(\*]])
+end
+
+--- @param bufnr integer
+--- @return string, fun(b: integer)
+local function modula2(bufnr)
+  local dialect = vim.g.modula2_default_dialect or 'pim'
+  local extension = vim.g.modula2_default_extension or ''
+
+  -- ignore unknown dialects or badly formatted tags
+  for _, line in ipairs(getlines(bufnr, 1, 200)) do
+    local matched_dialect, matched_extension = line:match('%(%*!m2(%w+)%+(%w+)%*%)')
+    if not matched_dialect then
+      matched_dialect = line:match('%(%*!m2(%w+)%*%)')
+    end
+    if matched_dialect then
+      if vim.tbl_contains({ 'iso', 'pim', 'r10' }, matched_dialect) then
+        dialect = matched_dialect
+      end
+      if vim.tbl_contains({ 'gm2' }, matched_extension) then
+        extension = matched_extension
+      end
+      break
+    end
+  end
+
+  return 'modula2',
+    function(b)
+      vim.api.nvim_buf_call(b, function()
+        fn['modula2#SetDialect'](dialect, extension)
+      end)
+    end
+end
+
+--- @type vim.filetype.mapfn
+function M.def(_, bufnr)
+  if vim.g.filetype_def == 'modula2' or is_modula2(bufnr) then
+    return modula2(bufnr)
+  end
+
+  if vim.g.filetype_def then
+    return vim.g.filetype_def
+  end
+  return 'def'
+end
+
 --- @type vim.filetype.mapfn
 function M.e(_, bufnr)
   if vim.g.filetype_euphoria then
@@ -906,14 +955,16 @@ end
 --- Determine if *.mod is ABB RAPID, LambdaProlog, Modula-2, Modsim III or go.mod
 --- @type vim.filetype.mapfn
 function M.mod(path, bufnr)
+  if vim.g.filetype_mod == 'modula2' or is_modula2(bufnr) then
+    return modula2(bufnr)
+  end
+
   if vim.g.filetype_mod then
     return vim.g.filetype_mod
   elseif matchregex(path, [[\c\<go\.mod$]]) then
     return 'gomod'
   elseif is_lprolog(bufnr) then
     return 'lprolog'
-  elseif matchregex(nextnonblank(bufnr, 1), [[\%(\<MODULE\s\+\w\+\s*;\|^\s*(\*\)]]) then
-    return 'modula2'
   elseif is_rapid(bufnr) then
     return 'rapid'
   end
diff --git a/runtime/makemenu.vim b/runtime/makemenu.vim
index 5d288e2f40..01f214cfa0 100644
--- a/runtime/makemenu.vim
+++ b/runtime/makemenu.vim
@@ -382,8 +382,10 @@ SynMenu M.MMIX:mmix
 SynMenu M.Modconf:modconf
 SynMenu M.Model:model
 SynMenu M.Modsim\ III:modsim3
-SynMenu M.Modula\ 2:modula2
-SynMenu M.Modula\ 3:modula3
+SynMenu M.Modula-2.R10\ (2010):modula2:r10
+SynMenu M.Modula-2.ISO\ (1994):modula2:iso
+SynMenu M.Modula-2.PIM\ (1985):modula2:pim
+SynMenu M.Modula-3:modula3
 SynMenu M.Monk:monk
 SynMenu M.Motorola\ S-Record:srec
 SynMenu M.Mplayer\ config:mplayerconf
diff --git a/runtime/synmenu.vim b/runtime/synmenu.vim
index ebab05ffed..edc6eabd1d 100644
--- a/runtime/synmenu.vim
+++ b/runtime/synmenu.vim
@@ -1,8 +1,8 @@
 " Vim support file to define the syntax selection menu
 " This file is normally sourced from menu.vim.
 "
-" Maintainer:	The Vim Project <https://github.com/vim/vim>
-" Last Change:	2023 Aug 10
+" Maintainer:		The Vim Project <https://github.com/vim/vim>
+" Last Change:		2024 Jan 04
 " Former Maintainer:	Bram Moolenaar <Bram@vim.org>
 
 " Define the SetSyn function, used for the Syntax menu entries.
@@ -16,6 +16,9 @@ fun! SetSyn(name)
     let use_fvwm_2 = 1
     let use_fvwm_1 = 0
     let name = "fvwm"
+  elseif a:name =~ '^modula2:\w\+$'
+    let [name, dialect] = split(a:name, ":")
+    call modula2#SetDialect(dialect)
   else
     let name = a:name
   endif
@@ -364,25 +367,27 @@ an 50.70.340 &Syntax.M.MMIX :cal SetSyn("mmix")<CR>
 an 50.70.350 &Syntax.M.Modconf :cal SetSyn("modconf")<CR>
 an 50.70.360 &Syntax.M.Model :cal SetSyn("model")<CR>
 an 50.70.370 &Syntax.M.Modsim\ III :cal SetSyn("modsim3")<CR>
-an 50.70.380 &Syntax.M.Modula\ 2 :cal SetSyn("modula2")<CR>
-an 50.70.390 &Syntax.M.Modula\ 3 :cal SetSyn("modula3")<CR>
-an 50.70.400 &Syntax.M.Monk :cal SetSyn("monk")<CR>
-an 50.70.410 &Syntax.M.Motorola\ S-Record :cal SetSyn("srec")<CR>
-an 50.70.420 &Syntax.M.Mplayer\ config :cal SetSyn("mplayerconf")<CR>
-an 50.70.430 &Syntax.M.MOO :cal SetSyn("moo")<CR>
-an 50.70.440 &Syntax.M.Mrxvtrc :cal SetSyn("mrxvtrc")<CR>
-an 50.70.450 &Syntax.M.MS-DOS/Windows.4DOS\ \.bat\ file :cal SetSyn("btm")<CR>
-an 50.70.460 &Syntax.M.MS-DOS/Windows.\.bat\/\.cmd\ file :cal SetSyn("dosbatch")<CR>
-an 50.70.470 &Syntax.M.MS-DOS/Windows.\.ini\ file :cal SetSyn("dosini")<CR>
-an 50.70.480 &Syntax.M.MS-DOS/Windows.Message\ text :cal SetSyn("msmessages")<CR>
-an 50.70.490 &Syntax.M.MS-DOS/Windows.Module\ Definition :cal SetSyn("def")<CR>
-an 50.70.500 &Syntax.M.MS-DOS/Windows.Registry :cal SetSyn("registry")<CR>
-an 50.70.510 &Syntax.M.MS-DOS/Windows.Resource\ file :cal SetSyn("rc")<CR>
-an 50.70.520 &Syntax.M.Msql :cal SetSyn("msql")<CR>
-an 50.70.530 &Syntax.M.MuPAD :cal SetSyn("mupad")<CR>
-an 50.70.540 &Syntax.M.Murphi :cal SetSyn("murphi")<CR>
-an 50.70.550 &Syntax.M.MUSHcode :cal SetSyn("mush")<CR>
-an 50.70.560 &Syntax.M.Muttrc :cal SetSyn("muttrc")<CR>
+an 50.70.380 &Syntax.M.Modula-2.R10\ (2010) :cal SetSyn("modula2:r10")<CR>
+an 50.70.390 &Syntax.M.Modula-2.ISO\ (1994) :cal SetSyn("modula2:iso")<CR>
+an 50.70.400 &Syntax.M.Modula-2.PIM\ (1985) :cal SetSyn("modula2:pim")<CR>
+an 50.70.410 &Syntax.M.Modula-3 :cal SetSyn("modula3")<CR>
+an 50.70.420 &Syntax.M.Monk :cal SetSyn("monk")<CR>
+an 50.70.430 &Syntax.M.Motorola\ S-Record :cal SetSyn("srec")<CR>
+an 50.70.440 &Syntax.M.Mplayer\ config :cal SetSyn("mplayerconf")<CR>
+an 50.70.450 &Syntax.M.MOO :cal SetSyn("moo")<CR>
+an 50.70.460 &Syntax.M.Mrxvtrc :cal SetSyn("mrxvtrc")<CR>
+an 50.70.470 &Syntax.M.MS-DOS/Windows.4DOS\ \.bat\ file :cal SetSyn("btm")<CR>
+an 50.70.480 &Syntax.M.MS-DOS/Windows.\.bat\/\.cmd\ file :cal SetSyn("dosbatch")<CR>
+an 50.70.490 &Syntax.M.MS-DOS/Windows.\.ini\ file :cal SetSyn("dosini")<CR>
+an 50.70.500 &Syntax.M.MS-DOS/Windows.Message\ text :cal SetSyn("msmessages")<CR>
+an 50.70.510 &Syntax.M.MS-DOS/Windows.Module\ Definition :cal SetSyn("def")<CR>
+an 50.70.520 &Syntax.M.MS-DOS/Windows.Registry :cal SetSyn("registry")<CR>
+an 50.70.530 &Syntax.M.MS-DOS/Windows.Resource\ file :cal SetSyn("rc")<CR>
+an 50.70.540 &Syntax.M.Msql :cal SetSyn("msql")<CR>
+an 50.70.550 &Syntax.M.MuPAD :cal SetSyn("mupad")<CR>
+an 50.70.560 &Syntax.M.Murphi :cal SetSyn("murphi")<CR>
+an 50.70.570 &Syntax.M.MUSHcode :cal SetSyn("mush")<CR>
+an 50.70.580 &Syntax.M.Muttrc :cal SetSyn("muttrc")<CR>
 an 50.80.100 &Syntax.NO.N1QL :cal SetSyn("n1ql")<CR>
 an 50.80.110 &Syntax.NO.Nanorc :cal SetSyn("nanorc")<CR>
 an 50.80.120 &Syntax.NO.Nastran\ input/DMAP :cal SetSyn("nastran")<CR>
diff --git a/runtime/syntax/modula2.vim b/runtime/syntax/modula2.vim
index 4a14cf1f6f..6a9f4af6aa 100644
--- a/runtime/syntax/modula2.vim
+++ b/runtime/syntax/modula2.vim
@@ -1,73 +1,16 @@
 " Vim syntax file
-" Language:	Modula 2
-" Maintainer:	pf@artcom0.north.de (Peter Funk)
-"   based on original work of Bram Moolenaar <Bram@vim.org>
-" Last Change:	2001 May 09
+" Language:		Modula-2
+" Maintainer:		Doug Kearns <dougkearns@gmail.com>
+" Previous Maintainer:	pf@artcom0.north.de (Peter Funk)
+" Last Change:		2024 Jan 04
 
-" quit when a syntax file was already loaded
 if exists("b:current_syntax")
   finish
 endif
 
-" Don't ignore case (Modula-2 is case significant). This is the default in vim
-
-" Especially emphasize headers of procedures and modules:
-syn region modula2Header matchgroup=modula2Header start="PROCEDURE " end="(" contains=modula2Ident oneline
-syn region modula2Header matchgroup=modula2Header start="MODULE " end=";" contains=modula2Ident oneline
-syn region modula2Header matchgroup=modula2Header start="BEGIN (\*" end="\*)" contains=modula2Ident oneline
-syn region modula2Header matchgroup=modula2Header start="END " end=";" contains=modula2Ident oneline
-syn region modula2Keyword start="END" end=";" contains=ALLBUT,modula2Ident oneline
-
-" Some very important keywords which should be emphasized more than others:
-syn keyword modula2AttKeyword CONST EXIT HALT RETURN TYPE VAR
-" All other keywords in alphabetical order:
-syn keyword modula2Keyword AND ARRAY BY CASE DEFINITION DIV DO ELSE
-syn keyword modula2Keyword ELSIF EXPORT FOR FROM IF IMPLEMENTATION IMPORT
-syn keyword modula2Keyword IN LOOP MOD NOT OF OR POINTER QUALIFIED RECORD
-syn keyword modula2Keyword SET THEN TO UNTIL WHILE WITH
-
-syn keyword modula2Type ADDRESS BITSET BOOLEAN CARDINAL CHAR INTEGER REAL WORD
-syn keyword modula2StdFunc ABS CAP CHR DEC EXCL INC INCL ORD SIZE TSIZE VAL
-syn keyword modula2StdConst FALSE NIL TRUE
-" The following may be discussed, since NEW and DISPOSE are some kind of
-" special builtin macro functions:
-syn keyword modula2StdFunc NEW DISPOSE
-" The following types are added later on and may be missing from older
-" Modula-2 Compilers (they are at least missing from the original report
-" by N.Wirth from March 1980 ;-)  Highlighting should apply nevertheless:
-syn keyword modula2Type BYTE LONGCARD LONGINT LONGREAL PROC SHORTCARD SHORTINT
-" same note applies to min and max, which were also added later to m2:
-syn keyword modula2StdFunc MAX MIN
-" The underscore was originally disallowed in m2 ids, it was also added later:
-syn match   modula2Ident " [A-Z,a-z][A-Z,a-z,0-9,_]*" contained
-
-" Comments may be nested in Modula-2:
-syn region modula2Comment start="(\*" end="\*)" contains=modula2Comment,modula2Todo
-syn keyword modula2Todo	contained TODO FIXME XXX
-
-" Strings
-syn region modula2String start=+"+ end=+"+
-syn region modula2String start="'" end="'"
-syn region modula2Set start="{" end="}"
-
-" Define the default highlighting.
-" Only when an item doesn't have highlighting yet
-
-hi def link modula2Ident		Identifier
-hi def link modula2StdConst	Boolean
-hi def link modula2Type		Identifier
-hi def link modula2StdFunc		Identifier
-hi def link modula2Header		Type
-hi def link modula2Keyword		Statement
-hi def link modula2AttKeyword	PreProc
-hi def link modula2Comment		Comment
-" The following is just a matter of taste (you want to try this instead):
-" hi modula2Comment term=bold ctermfg=DarkBlue guifg=Blue gui=bold
-hi def link modula2Todo		Todo
-hi def link modula2String		String
-hi def link modula2Set		String
-
+let dialect = modula2#GetDialect()
+exe "runtime! syntax/modula2/opt/" .. dialect .. ".vim"
 
 let b:current_syntax = "modula2"
 
-" vim: ts=8
+" vim: nowrap sw=2 sts=2 ts=8 noet:
diff --git a/runtime/syntax/modula2/opt/iso.vim b/runtime/syntax/modula2/opt/iso.vim
new file mode 100644
index 0000000000..5bd24f6885
--- /dev/null
+++ b/runtime/syntax/modula2/opt/iso.vim
@@ -0,0 +1,380 @@
+" Vim syntax file
+" Language:    Modula-2 (ISO)
+" Maintainer:  B.Kowarsch <trijezdci@moc.liamg>
+" Last Change: 2016 August 22
+
+" ----------------------------------------------------
+" THIS FILE IS LICENSED UNDER THE VIM LICENSE
+" see https://github.com/vim/vim/blob/master/LICENSE
+" ----------------------------------------------------
+
+" Remarks:
+" Vim Syntax files are available for the following Modula-2 dialects:
+" * for the PIM dialect : m2pim.vim
+" * for the ISO dialect : m2iso.vim (this file)
+" * for the R10 dialect : m2r10.vim
+
+" -----------------------------------------------------------------------------
+" This syntax description follows ISO standard IS-10514 (aka ISO Modula-2)
+" with the addition of the following language extensions:
+" * non-standard types LONGCARD and LONGBITSET
+" * non-nesting code disabling tags ?< and >? at the start of a line
+" -----------------------------------------------------------------------------
+
+" Parameters:
+"
+" Vim's filetype script recognises Modula-2 dialect tags within the first 200
+" lines of Modula-2 .def and .mod input files.  The script sets filetype and
+" dialect automatically when a valid dialect tag is found in the input file.
+" The dialect tag for the ISO dialect is (*!m2iso*).  It is recommended to put
+" the tag immediately after the module header in the Modula-2 input file.
+"
+" Example:
+"  DEFINITION MODULE Foolib; (*!m2iso*)
+"
+" Variable g:modula2_default_dialect sets the default Modula-2 dialect when the
+" dialect cannot be determined from the contents of the Modula-2 input file:
+" if defined and set to 'm2iso', the default dialect is ISO.
+"
+" Variable g:modula2_iso_allow_lowline controls support for lowline in identifiers:
+" if defined and set to a non-zero value, they are recognised, otherwise not
+"
+" Variable g:modula2_iso_disallow_octals controls the rendering of octal literals:
+" if defined and set to a non-zero value, they are rendered as errors.
+"
+" Variable g:modula2_iso_disallow_synonyms controls the rendering of @, & and ~:
+" if defined and set to a non-zero value, they are rendered as errors.
+"
+" Variables may be defined in Vim startup file .vimrc
+"
+" Examples:
+"  let g:modula2_default_dialect = 'm2iso'
+"  let g:modula2_iso_allow_lowline = 1
+"  let g:modula2_iso_disallow_octals = 1
+"  let g:modula2_iso_disallow_synonyms = 1
+
+
+if exists("b:current_syntax")
+  finish
+endif
+
+" Modula-2 is case sensitive
+syn case match
+
+
+" -----------------------------------------------------------------------------
+" Reserved Words
+" -----------------------------------------------------------------------------
+syn keyword modula2Resword AND ARRAY BEGIN BY CASE CONST DEFINITION DIV DO ELSE
+syn keyword modula2Resword ELSIF EXCEPT EXIT EXPORT FINALLY FOR FORWARD FROM IF
+syn keyword modula2Resword IMPLEMENTATION IMPORT IN LOOP MOD NOT OF OR PACKEDSET
+syn keyword modula2Resword POINTER QUALIFIED RECORD REPEAT REM RETRY RETURN SET
+syn keyword modula2Resword THEN TO TYPE UNTIL VAR WHILE WITH
+
+
+" -----------------------------------------------------------------------------
+" Builtin Constant Identifiers
+" -----------------------------------------------------------------------------
+syn keyword modula2ConstIdent FALSE NIL TRUE INTERRUPTIBLE UNINTERRUPTIBLE
+
+
+" -----------------------------------------------------------------------------
+" Builtin Type Identifiers
+" -----------------------------------------------------------------------------
+syn keyword modula2TypeIdent BITSET BOOLEAN CHAR PROC
+syn keyword modula2TypeIdent CARDINAL INTEGER LONGINT REAL LONGREAL
+syn keyword modula2TypeIdent COMPLEX LONGCOMPLEX PROTECTION
+
+
+" -----------------------------------------------------------------------------
+" Builtin Procedure and Function Identifiers
+" -----------------------------------------------------------------------------
+syn keyword modula2ProcIdent CAP DEC EXCL HALT INC INCL
+syn keyword modula2FuncIdent ABS CHR CMPLX FLOAT HIGH IM INT LENGTH LFLOAT MAX MIN
+syn keyword modula2FuncIdent ODD ORD RE SIZE TRUNC VAL
+
+
+" -----------------------------------------------------------------------------
+" Wirthian Macro Identifiers
+" -----------------------------------------------------------------------------
+syn keyword modula2MacroIdent NEW DISPOSE
+
+
+" -----------------------------------------------------------------------------
+" Unsafe Facilities via Pseudo-Module SYSTEM
+" -----------------------------------------------------------------------------
+syn keyword modula2UnsafeIdent ADDRESS BYTE LOC WORD
+syn keyword modula2UnsafeIdent ADR CAST TSIZE SYSTEM
+syn keyword modula2UnsafeIdent MAKEADR ADDADR SUBADR DIFADR ROTATE SHIFT
+
+
+" -----------------------------------------------------------------------------
+" Non-Portable Language Extensions
+" -----------------------------------------------------------------------------
+syn keyword modula2NonPortableIdent LONGCARD LONGBITSET
+
+
+" -----------------------------------------------------------------------------
+" User Defined Identifiers
+" -----------------------------------------------------------------------------
+syn match modula2Ident "[a-zA-Z][a-zA-Z0-9]*\(_\)\@!"
+syn match modula2LowLineIdent "[a-zA-Z][a-zA-Z0-9]*\(_[a-zA-Z0-9]\+\)\+"
+
+
+" -----------------------------------------------------------------------------
+" String Literals
+" -----------------------------------------------------------------------------
+syn region modula2String start=/"/ end=/"/ oneline
+syn region modula2String start=/'/ end=/'/ oneline
+
+
+" -----------------------------------------------------------------------------
+" Numeric Literals
+" -----------------------------------------------------------------------------
+syn match modula2Num
+  \ "\(\([0-7]\+\)[BC]\@!\|[89]\)[0-9]*\(\.[0-9]\+\([eE][+-]\?[0-9]\+\)\?\)\?"
+syn match modula2Num "[0-9A-F]\+H"
+syn match modula2Octal "[0-7]\+[BC]"
+
+
+" -----------------------------------------------------------------------------
+" Punctuation
+" -----------------------------------------------------------------------------
+syn match modula2Punctuation
+  \ "\.\|[,:;]\|\*\|[/+-]\|\#\|[=<>]\|\^\|\[\|\]\|(\(\*\)\@!\|[){}]"
+syn match modula2Synonym "[@&~]"
+
+
+" -----------------------------------------------------------------------------
+" Pragmas
+" -----------------------------------------------------------------------------
+syn region modula2Pragma start="<\*" end="\*>"
+syn match modula2DialectTag "(\*!m2iso\(+[a-z0-9]\+\)\?\*)"
+
+" -----------------------------------------------------------------------------
+" Block Comments
+" -----------------------------------------------------------------------------
+syn region modula2Comment start="(\*\(!m2iso\(+[a-z0-9]\+\)\?\*)\)\@!" end="\*)"
+  \ contains = modula2Comment, modula2CommentKey, modula2TechDebtMarker
+syn match modula2CommentKey "[Aa]uthor[s]\?\|[Cc]opyright\|[Ll]icense\|[Ss]ynopsis"
+syn match modula2CommentKey "\([Pp]re\|[Pp]ost\|[Ee]rror\)\-condition[s]\?:"
+
+
+" -----------------------------------------------------------------------------
+" Technical Debt Markers
+" -----------------------------------------------------------------------------
+syn keyword modula2TechDebtMarker contained DEPRECATED FIXME
+syn match modula2TechDebtMarker "TODO[:]\?" contained
+
+" -----------------------------------------------------------------------------
+" Disabled Code Sections
+" -----------------------------------------------------------------------------
+syn region modula2DisabledCode start="^?<" end="^>?"
+
+
+" -----------------------------------------------------------------------------
+" Headers
+" -----------------------------------------------------------------------------
+" !!! this section must be second last !!!
+
+" new module header
+syn match modula2ModuleHeader
+  \ "MODULE\( [A-Z][a-zA-Z0-9]*\)\?"
+  \ contains = modula2ReswordModule, modula2ModuleIdent
+
+syn match modula2ModuleIdent
+  \ "[A-Z][a-zA-Z0-9]*" contained
+
+syn match modula2ModuleTail
+  \ "END [A-Z][a-zA-Z0-9]*\.$"
+  \ contains = modula2ReswordEnd, modula2ModuleIdent, modula2Punctuation
+
+" new procedure header
+syn match modula2ProcedureHeader
+  \ "PROCEDURE\( [a-zA-Z][a-zA-Z0-9]*\(_[a-zA-Z0-9]\+\)*\)\?"
+  \ contains = modula2ReswordProcedure,
+  \ modula2ProcedureIdent, modula2ProcedureLowlineIdent, modula2IllegalChar, modula2IllegalIdent
+
+syn match modula2ProcedureIdent
+  \ "\([a-zA-Z]\)\([a-zA-Z0-9]*\)" contained
+
+syn match modula2ProcedureLowlineIdent
+  \ "[a-zA-Z][a-zA-Z0-9]*\(_[a-zA-Z0-9]\+\)\+" contained
+
+syn match modula2ProcedureTail
+  \ "END\( \([a-zA-Z][a-zA-Z0-9]*\(_[a-zA-Z0-9]\+\)*\)[.;]$\)\?"
+  \ contains = modula2ReswordEnd,
+  \ modula2ProcedureIdent, modula2ProcedureLowLineIdent,
+  \ modula2Punctuation, modula2IllegalChar, modula2IllegalIdent
+
+syn keyword modula2ReswordModule contained MODULE
+syn keyword modula2ReswordProcedure contained PROCEDURE
+syn keyword modula2ReswordEnd contained END
+
+
+" -----------------------------------------------------------------------------
+" Illegal Symbols
+" -----------------------------------------------------------------------------
+" !!! this section must be last !!!
+
+" any '`' '!' '$' '%' or '\'
+syn match modula2IllegalChar "[`!$%\\]"
+
+" any solitary sequence of '_'
+syn match modula2IllegalChar "\<_\+\>"
+
+" any '?' at start of line if not followed by '<'
+syn match modula2IllegalChar "^?\(<\)\@!"
+
+" any '?' not following '>' at start of line
+syn match modula2IllegalChar "\(\(^>\)\|\(^\)\)\@<!?"
+
+" any identifiers with leading occurrences of '_'
+syn match modula2IllegalIdent "_\+[a-zA-Z][a-zA-Z0-9]*\(_\+[a-zA-Z0-9]*\)*"
+
+" any identifiers containing consecutive occurences of '_'
+syn match modula2IllegalIdent
+  \ "[a-zA-Z][a-zA-Z0-9]*\(_[a-zA-Z0-9]\+\)*\(__\+[a-zA-Z0-9]\+\(_[a-zA-Z0-9]\+\)*\)\+"
+
+" any identifiers with trailing occurrences of '_'
+syn match modula2IllegalIdent "[a-zA-Z][a-zA-Z0-9]*\(_\+[a-zA-Z0-9]\+\)*_\+\>"
+
+
+" -----------------------------------------------------------------------------
+" Define Rendering Styles
+" -----------------------------------------------------------------------------
+
+" highlight default link modula2PredefIdentStyle Keyword
+" highlight default link modula2ConstIdentStyle modula2PredefIdentStyle
+" highlight default link modula2TypeIdentStyle modula2PredefIdentStyle
+" highlight default link modula2ProcIdentStyle modula2PredefIdentStyle
+" highlight default link modula2FuncIdentStyle modula2PredefIdentStyle
+" highlight default link modula2MacroIdentStyle modula2PredefIdentStyle
+
+highlight default link modula2ConstIdentStyle Constant
+highlight default link modula2TypeIdentStyle Type
+highlight default link modula2ProcIdentStyle Function
+highlight default link modula2FuncIdentStyle Function
+highlight default link modula2MacroIdentStyle Function
+highlight default link modula2UnsafeIdentStyle Question
+highlight default link modula2NonPortableIdentStyle Question
+highlight default link modula2StringLiteralStyle String
+highlight default link modula2CommentStyle Comment
+highlight default link modula2PragmaStyle PreProc
+highlight default link modula2DialectTagStyle SpecialComment
+highlight default link modula2TechDebtMarkerStyle SpecialComment
+highlight default link modula2ReswordStyle Keyword
+highlight default link modula2HeaderIdentStyle Function
+highlight default link modula2UserDefIdentStyle Normal
+highlight default link modula2NumericLiteralStyle Number
+highlight default link modula2PunctuationStyle Delimiter
+highlight default link modula2CommentKeyStyle SpecialComment
+highlight default link modula2DisabledCodeStyle NonText
+
+" -----------------------------------------------------------------------------
+" Assign Rendering Styles
+" -----------------------------------------------------------------------------
+
+" headers
+highlight default link modula2ModuleIdent modula2HeaderIdentStyle
+highlight default link modula2ProcedureIdent modula2HeaderIdentStyle
+highlight default link modula2ModuleHeader Normal
+highlight default link modula2ModuleTail Normal
+highlight default link modula2ProcedureHeader Normal
+highlight default link modula2ProcedureTail Normal
+
+" lowline identifiers are rendered as errors if g:modula2_iso_allow_lowline is unset
+if exists("g:modula2_iso_allow_lowline")
+  if g:modula2_iso_allow_lowline != 0
+    highlight default link modula2ProcedureLowlineIdent modula2HeaderIdentStyle
+  else
+    highlight default link modula2ProcedureLowlineIdent Error
+  endif
+else
+  highlight default link modula2ProcedureLowlineIdent modula2HeaderIdentStyle
+endif
+
+" reserved words
+highlight default link modula2Resword modula2ReswordStyle
+highlight default link modula2ReswordModule modula2ReswordStyle
+highlight default link modula2ReswordProcedure modula2ReswordStyle
+highlight default link modula2ReswordEnd modula2ReswordStyle
+
+" predefined identifiers
+highlight default link modula2ConstIdent modula2ConstIdentStyle
+highlight default link modula2TypeIdent modula2TypeIdentStyle
+highlight default link modula2ProcIdent modula2ProcIdentStyle
+highlight default link modula2FuncIdent modula2FuncIdentStyle
+highlight default link modula2MacroIdent modula2MacroIdentStyle
+
+" unsafe and non-portable identifiers
+highlight default link modula2UnsafeIdent modula2UnsafeIdentStyle
+highlight default link modula2NonPortableIdent modula2NonPortableIdentStyle
+
+" user defined identifiers
+highlight default link modula2Ident modula2UserDefIdentStyle
+
+" lowline identifiers are rendered as errors if g:modula2_iso_allow_lowline is unset
+if exists("g:modula2_iso_allow_lowline")
+  if g:modula2_iso_allow_lowline != 0
+    highlight default link modula2LowLineIdent modula2UserDefIdentStyle
+  else
+    highlight default link modula2LowLineIdent Error
+  endif
+else
+  highlight default link modula2LowLineIdent modula2UserDefIdentStyle
+endif
+
+" literals
+highlight default link modula2String modula2StringLiteralStyle
+highlight default link modula2Num modula2NumericLiteralStyle
+
+" octal literals are rendered as errors if g:modula2_iso_disallow_octals is set
+if exists("g:modula2_iso_disallow_octals")
+  if g:modula2_iso_disallow_octals != 0
+    highlight default link modula2Octal Error
+  else
+    highlight default link modula2Octal modula2NumericLiteralStyle
+  endif
+else
+  highlight default link modula2Octal modula2NumericLiteralStyle
+endif
+
+" punctuation
+highlight default link modula2Punctuation modula2PunctuationStyle
+
+" synonyms & and ~ are rendered as errors if g:modula2_iso_disallow_synonyms is set
+if exists("g:modula2_iso_disallow_synonyms")
+  if g:modula2_iso_disallow_synonyms != 0
+    highlight default link modula2Synonym Error
+  else
+    highlight default link modula2Synonym modula2PunctuationStyle
+  endif
+else
+  highlight default link modula2Synonym modula2PunctuationStyle
+endif
+
+" pragmas
+highlight default link modula2Pragma modula2PragmaStyle
+highlight default link modula2DialectTag modula2DialectTagStyle
+
+" comments
+highlight default link modula2Comment modula2CommentStyle
+highlight default link modula2CommentKey modula2CommentKeyStyle
+
+" technical debt markers
+highlight default link modula2TechDebtMarker modula2TechDebtMarkerStyle
+
+" disabled code
+highlight default link modula2DisabledCode modula2DisabledCodeStyle
+
+" illegal symbols
+highlight default link modula2IllegalChar Error
+highlight default link modula2IllegalIdent Error
+
+
+let b:current_syntax = "modula2"
+
+" vim: ts=4
+
+" END OF FILE
diff --git a/runtime/syntax/modula2/opt/pim.vim b/runtime/syntax/modula2/opt/pim.vim
new file mode 100644
index 0000000000..1626db91cf
--- /dev/null
+++ b/runtime/syntax/modula2/opt/pim.vim
@@ -0,0 +1,377 @@
+" Vim syntax file
+" Language:    Modula-2 (PIM)
+" Maintainer:  B.Kowarsch <trijezdci@moc.liamg>
+" Last Change: 2016 August 22
+
+" ----------------------------------------------------
+" THIS FILE IS LICENSED UNDER THE VIM LICENSE
+" see https://github.com/vim/vim/blob/master/LICENSE
+" ----------------------------------------------------
+
+" Remarks:
+" Vim Syntax files are available for the following Modula-2 dialects:
+" * for the PIM dialect : m2pim.vim (this file)
+" * for the ISO dialect : m2iso.vim
+" * for the R10 dialect : m2r10.vim
+
+" -----------------------------------------------------------------------------
+" This syntax description follows the 3rd and 4th editions of N.Wirth's Book
+" Programming in Modula-2 (aka PIM) plus the following language extensions:
+" * non-leading, non-trailing, non-consecutive lowlines _ in identifiers
+" * widely supported non-standard types BYTE, LONGCARD and LONGBITSET
+" * non-nesting code disabling tags ?< and >? at the start of a line
+" -----------------------------------------------------------------------------
+
+" Parameters:
+"
+" Vim's filetype script recognises Modula-2 dialect tags within the first 200
+" lines of Modula-2 .def and .mod input files.  The script sets filetype and
+" dialect automatically when a valid dialect tag is found in the input file.
+" The dialect tag for the PIM dialect is (*!m2pim*).  It is recommended to put
+" the tag immediately after the module header in the Modula-2 input file.
+"
+" Example:
+"  DEFINITION MODULE Foolib; (*!m2pim*)
+"
+" Variable g:modula2_default_dialect sets the default Modula-2 dialect when the
+" dialect cannot be determined from the contents of the Modula-2 input file:
+" if defined and set to 'm2pim', the default dialect is PIM.
+"
+" Variable g:modula2_pim_allow_lowline controls support for lowline in identifiers:
+" if defined and set to a non-zero value, they are recognised, otherwise not
+"
+" Variable g:modula2_pim_disallow_octals controls the rendering of octal literals:
+" if defined and set to a non-zero value, they are rendered as errors.
+"
+" Variable g:modula2_pim_disallow_synonyms controls the rendering of & and ~:
+" if defined and set to a non-zero value, they are rendered as errors.
+"
+" Variables may be defined in Vim startup file .vimrc
+"
+" Examples:
+"  let g:modula2_default_dialect = 'm2pim'
+"  let g:modula2_pim_allow_lowline = 1
+"  let g:modula2_pim_disallow_octals = 1
+"  let g:modula2_pim_disallow_synonyms = 1
+
+
+if exists("b:current_syntax")
+  finish
+endif
+
+" Modula-2 is case sensitive
+syn case match
+
+
+" -----------------------------------------------------------------------------
+" Reserved Words
+" -----------------------------------------------------------------------------
+syn keyword modula2Resword AND ARRAY BEGIN BY CASE CONST DEFINITION DIV DO ELSE
+syn keyword modula2Resword ELSIF EXIT EXPORT FOR FROM IF IMPLEMENTATION IMPORT
+syn keyword modula2Resword IN LOOP MOD NOT OF OR POINTER QUALIFIED RECORD REPEAT
+syn keyword modula2Resword RETURN SET THEN TO TYPE UNTIL VAR WHILE WITH
+
+
+" -----------------------------------------------------------------------------
+" Builtin Constant Identifiers
+" -----------------------------------------------------------------------------
+syn keyword modula2ConstIdent FALSE NIL TRUE
+
+
+" -----------------------------------------------------------------------------
+" Builtin Type Identifiers
+" -----------------------------------------------------------------------------
+syn keyword modula2TypeIdent BITSET BOOLEAN CHAR PROC
+syn keyword modula2TypeIdent CARDINAL INTEGER LONGINT REAL LONGREAL
+
+
+" -----------------------------------------------------------------------------
+" Builtin Procedure and Function Identifiers
+" -----------------------------------------------------------------------------
+syn keyword modula2ProcIdent CAP DEC EXCL HALT INC INCL
+syn keyword modula2FuncIdent ABS CHR FLOAT HIGH MAX MIN ODD ORD SIZE TRUNC VAL
+
+
+" -----------------------------------------------------------------------------
+" Wirthian Macro Identifiers
+" -----------------------------------------------------------------------------
+syn keyword modula2MacroIdent NEW DISPOSE
+
+
+" -----------------------------------------------------------------------------
+" Unsafe Facilities via Pseudo-Module SYSTEM
+" -----------------------------------------------------------------------------
+syn keyword modula2UnsafeIdent ADDRESS PROCESS WORD
+syn keyword modula2UnsafeIdent ADR TSIZE NEWPROCESS TRANSFER SYSTEM
+
+
+" -----------------------------------------------------------------------------
+" Non-Portable Language Extensions
+" -----------------------------------------------------------------------------
+syn keyword modula2NonPortableIdent BYTE LONGCARD LONGBITSET
+
+
+" -----------------------------------------------------------------------------
+" User Defined Identifiers
+" -----------------------------------------------------------------------------
+syn match modula2Ident "[a-zA-Z][a-zA-Z0-9]*\(_\)\@!"
+syn match modula2LowLineIdent "[a-zA-Z][a-zA-Z0-9]*\(_[a-zA-Z0-9]\+\)\+"
+
+
+" -----------------------------------------------------------------------------
+" String Literals
+" -----------------------------------------------------------------------------
+syn region modula2String start=/"/ end=/"/ oneline
+syn region modula2String start=/'/ end=/'/ oneline
+
+
+" -----------------------------------------------------------------------------
+" Numeric Literals
+" -----------------------------------------------------------------------------
+syn match modula2Num
+  \ "\(\([0-7]\+\)[BC]\@!\|[89]\)[0-9]*\(\.[0-9]\+\([eE][+-]\?[0-9]\+\)\?\)\?"
+syn match modula2Num "[0-9A-F]\+H"
+syn match modula2Octal "[0-7]\+[BC]"
+
+
+" -----------------------------------------------------------------------------
+" Punctuation
+" -----------------------------------------------------------------------------
+syn match modula2Punctuation
+  \ "\.\|[,:;]\|\*\|[/+-]\|\#\|[=<>]\|\^\|\[\|\]\|(\(\*\)\@!\|[){}]"
+syn match modula2Synonym "[&~]"
+
+
+" -----------------------------------------------------------------------------
+" Pragmas
+" -----------------------------------------------------------------------------
+syn region modula2Pragma start="(\*\$" end="\*)"
+syn match modula2DialectTag "(\*!m2pim\(+[a-z0-9]\+\)\?\*)"
+
+" -----------------------------------------------------------------------------
+" Block Comments
+" -----------------------------------------------------------------------------
+syn region modula2Comment start="(\*\(\$\|!m2pim\(+[a-z0-9]\+\)\?\*)\)\@!" end="\*)"
+  \ contains = modula2Comment, modula2CommentKey, modula2TechDebtMarker
+syn match modula2CommentKey "[Aa]uthor[s]\?\|[Cc]opyright\|[Ll]icense\|[Ss]ynopsis"
+syn match modula2CommentKey "\([Pp]re\|[Pp]ost\|[Ee]rror\)\-condition[s]\?:"
+
+
+" -----------------------------------------------------------------------------
+" Technical Debt Markers
+" -----------------------------------------------------------------------------
+syn keyword modula2TechDebtMarker contained DEPRECATED FIXME
+syn match modula2TechDebtMarker "TODO[:]\?" contained
+
+" -----------------------------------------------------------------------------
+" Disabled Code Sections
+" -----------------------------------------------------------------------------
+syn region modula2DisabledCode start="^?<" end="^>?"
+
+
+" -----------------------------------------------------------------------------
+" Headers
+" -----------------------------------------------------------------------------
+" !!! this section must be second last !!!
+
+" new module header
+syn match modula2ModuleHeader
+  \ "MODULE\( [A-Z][a-zA-Z0-9]*\)\?"
+  \ contains = modula2ReswordModule, modula2ModuleIdent
+
+syn match modula2ModuleIdent
+  \ "[A-Z][a-zA-Z0-9]*" contained
+
+syn match modula2ModuleTail
+  \ "END [A-Z][a-zA-Z0-9]*\.$"
+  \ contains = modula2ReswordEnd, modula2ModuleIdent, modula2Punctuation
+
+" new procedure header
+syn match modula2ProcedureHeader
+  \ "PROCEDURE\( [a-zA-Z][a-zA-Z0-9]*\(_[a-zA-Z0-9]\+\)*\)\?"
+  \ contains = modula2ReswordProcedure,
+  \ modula2ProcedureIdent, modula2ProcedureLowlineIdent, modula2IllegalChar, modula2IllegalIdent
+
+syn match modula2ProcedureIdent
+  \ "\([a-zA-Z]\)\([a-zA-Z0-9]*\)" contained
+
+syn match modula2ProcedureLowlineIdent
+  \ "[a-zA-Z][a-zA-Z0-9]*\(_[a-zA-Z0-9]\+\)\+" contained
+
+syn match modula2ProcedureTail
+  \ "END\( \([a-zA-Z][a-zA-Z0-9]*\(_[a-zA-Z0-9]\+\)*\)[.;]$\)\?"
+  \ contains = modula2ReswordEnd,
+  \ modula2ProcedureIdent, modula2ProcedureLowLineIdent,
+  \ modula2Punctuation, modula2IllegalChar, modula2IllegalIdent
+
+syn keyword modula2ReswordModule contained MODULE
+syn keyword modula2ReswordProcedure contained PROCEDURE
+syn keyword modula2ReswordEnd contained END
+
+
+" -----------------------------------------------------------------------------
+" Illegal Symbols
+" -----------------------------------------------------------------------------
+" !!! this section must be last !!!
+
+" any '`' '!' '@ ''$' '%' or '\'
+syn match modula2IllegalChar "[`!@$%\\]"
+
+" any solitary sequence of '_'
+syn match modula2IllegalChar "\<_\+\>"
+
+" any '?' at start of line if not followed by '<'
+syn match modula2IllegalChar "^?\(<\)\@!"
+
+" any '?' not following '>' at start of line
+syn match modula2IllegalChar "\(\(^>\)\|\(^\)\)\@<!?"
+
+" any identifiers with leading occurrences of '_'
+syn match modula2IllegalIdent "_\+[a-zA-Z][a-zA-Z0-9]*\(_\+[a-zA-Z0-9]*\)*"
+
+" any identifiers containing consecutive occurences of '_'
+syn match modula2IllegalIdent
+  \ "[a-zA-Z][a-zA-Z0-9]*\(_[a-zA-Z0-9]\+\)*\(__\+[a-zA-Z0-9]\+\(_[a-zA-Z0-9]\+\)*\)\+"
+
+" any identifiers with trailing occurrences of '_'
+syn match modula2IllegalIdent "[a-zA-Z][a-zA-Z0-9]*\(_\+[a-zA-Z0-9]\+\)*_\+\>"
+
+
+" -----------------------------------------------------------------------------
+" Define Rendering Styles
+" -----------------------------------------------------------------------------
+
+" highlight default link modula2PredefIdentStyle Keyword
+" highlight default link modula2ConstIdentStyle modula2PredefIdentStyle
+" highlight default link modula2TypeIdentStyle modula2PredefIdentStyle
+" highlight default link modula2ProcIdentStyle modula2PredefIdentStyle
+" highlight default link modula2FuncIdentStyle modula2PredefIdentStyle
+" highlight default link modula2MacroIdentStyle modula2PredefIdentStyle
+
+highlight default link modula2ConstIdentStyle Constant
+highlight default link modula2TypeIdentStyle Type
+highlight default link modula2ProcIdentStyle Function
+highlight default link modula2FuncIdentStyle Function
+highlight default link modula2MacroIdentStyle Function
+highlight default link modula2UnsafeIdentStyle Question
+highlight default link modula2NonPortableIdentStyle Question
+highlight default link modula2StringLiteralStyle String
+highlight default link modula2CommentStyle Comment
+highlight default link modula2PragmaStyle PreProc
+highlight default link modula2DialectTagStyle SpecialComment
+highlight default link modula2TechDebtMarkerStyle SpecialComment
+highlight default link modula2ReswordStyle Keyword
+highlight default link modula2HeaderIdentStyle Function
+highlight default link modula2UserDefIdentStyle Normal
+highlight default link modula2NumericLiteralStyle Number
+highlight default link modula2PunctuationStyle Delimiter
+highlight default link modula2CommentKeyStyle SpecialComment
+highlight default link modula2DisabledCodeStyle NonText
+
+" -----------------------------------------------------------------------------
+" Assign Rendering Styles
+" -----------------------------------------------------------------------------
+
+" headers
+highlight default link modula2ModuleIdent modula2HeaderIdentStyle
+highlight default link modula2ProcedureIdent modula2HeaderIdentStyle
+highlight default link modula2ModuleHeader Normal
+highlight default link modula2ModuleTail Normal
+highlight default link modula2ProcedureHeader Normal
+highlight default link modula2ProcedureTail Normal
+
+" lowline identifiers are rendered as errors if g:modula2_pim_allow_lowline is unset
+if exists("g:modula2_pim_allow_lowline")
+  if g:modula2_pim_allow_lowline != 0
+    highlight default link modula2ProcedureLowlineIdent modula2HeaderIdentStyle
+  else
+    highlight default link modula2ProcedureLowlineIdent Error
+  endif
+else
+  highlight default link modula2ProcedureLowlineIdent Error
+endif
+
+" reserved words
+highlight default link modula2Resword modula2ReswordStyle
+highlight default link modula2ReswordModule modula2ReswordStyle
+highlight default link modula2ReswordProcedure modula2ReswordStyle
+highlight default link modula2ReswordEnd modula2ReswordStyle
+
+" predefined identifiers
+highlight default link modula2ConstIdent modula2ConstIdentStyle
+highlight default link modula2TypeIdent modula2TypeIdentStyle
+highlight default link modula2ProcIdent modula2ProcIdentStyle
+highlight default link modula2FuncIdent modula2FuncIdentStyle
+highlight default link modula2MacroIdent modula2MacroIdentStyle
+
+" unsafe and non-portable identifiers
+highlight default link modula2UnsafeIdent modula2UnsafeIdentStyle
+highlight default link modula2NonPortableIdent modula2NonPortableIdentStyle
+
+" user defined identifiers
+highlight default link modula2Ident modula2UserDefIdentStyle
+
+" lowline identifiers are rendered as errors if g:modula2_pim_allow_lowline is unset
+if exists("g:modula2_pim_allow_lowline")
+  if g:modula2_pim_allow_lowline != 0
+    highlight default link modula2LowLineIdent modula2UserDefIdentStyle
+  else
+    highlight default link modula2LowLineIdent Error
+  endif
+else
+  highlight default link modula2LowLineIdent Error
+endif
+
+" literals
+highlight default link modula2String modula2StringLiteralStyle
+highlight default link modula2Num modula2NumericLiteralStyle
+
+" octal literals are rendered as errors if g:modula2_pim_disallow_octals is set
+if exists("g:modula2_pim_disallow_octals")
+  if g:modula2_pim_disallow_octals != 0
+    highlight default link modula2Octal Error
+  else
+    highlight default link modula2Octal modula2NumericLiteralStyle
+  endif
+else
+  highlight default link modula2Octal modula2NumericLiteralStyle
+endif
+
+" punctuation
+highlight default link modula2Punctuation modula2PunctuationStyle
+
+" synonyms & and ~ are rendered as errors if g:modula2_pim_disallow_synonyms is set
+if exists("g:modula2_pim_disallow_synonyms")
+  if g:modula2_pim_disallow_synonyms != 0
+    highlight default link modula2Synonym Error
+  else
+    highlight default link modula2Synonym modula2PunctuationStyle
+  endif
+else
+  highlight default link modula2Synonym modula2PunctuationStyle
+endif
+
+" pragmas
+highlight default link modula2Pragma modula2PragmaStyle
+highlight default link modula2DialectTag modula2DialectTagStyle
+
+" comments
+highlight default link modula2Comment modula2CommentStyle
+highlight default link modula2CommentKey modula2CommentKeyStyle
+
+" technical debt markers
+highlight default link modula2TechDebtMarker modula2TechDebtMarkerStyle
+
+" disabled code
+highlight default link modula2DisabledCode modula2DisabledCodeStyle
+
+" illegal symbols
+highlight default link modula2IllegalChar Error
+highlight default link modula2IllegalIdent Error
+
+
+let b:current_syntax = "modula2"
+
+" vim: ts=4
+
+" END OF FILE
diff --git a/runtime/syntax/modula2/opt/r10.vim b/runtime/syntax/modula2/opt/r10.vim
new file mode 100644
index 0000000000..775f498dfb
--- /dev/null
+++ b/runtime/syntax/modula2/opt/r10.vim
@@ -0,0 +1,452 @@
+" Vim syntax file
+" Language:    Modula-2 (R10)
+" Maintainer:  B.Kowarsch <trijezdci@moc.liamg>
+" Last Change: 2020 June 18 (moved repository from bb to github)
+
+" ----------------------------------------------------
+" THIS FILE IS LICENSED UNDER THE VIM LICENSE
+" see https://github.com/vim/vim/blob/master/LICENSE
+" ----------------------------------------------------
+
+" Remarks:
+" Vim Syntax files are available for the following Modula-2 dialects:
+" * for the PIM dialect : m2pim.vim
+" * for the ISO dialect : m2iso.vim
+" * for the R10 dialect : m2r10.vim (this file)
+
+" -----------------------------------------------------------------------------
+" This syntax description follows the Modula-2 Revision 2010 language report
+" (Kowarsch and Sutcliffe, 2015) available at http://modula-2.info/m2r10.
+" -----------------------------------------------------------------------------
+
+" Parameters:
+"
+" Vim's filetype script recognises Modula-2 dialect tags within the first 200
+" lines of Modula-2 .def and .mod input files.  The script sets filetype and
+" dialect automatically when a valid dialect tag is found in the input file.
+" The dialect tag for the R10 dialect is (*!m2r10*).  It is recommended to put
+" the tag immediately after the module header in the Modula-2 input file.
+"
+" Example:
+"  DEFINITION MODULE Foolib; (*!m2r10*)
+"
+" Variable g:modula2_default_dialect sets the default Modula-2 dialect when the
+" dialect cannot be determined from the contents of the Modula-2 input file:
+" if defined and set to 'm2r10', the default dialect is R10.
+"
+" Variable g:modula2_r10_allow_lowline controls support for lowline in identifiers:
+" if defined and set to a non-zero value, they are recognised, otherwise not
+"
+" Variables may be defined in Vim startup file .vimrc
+"
+" Examples:
+"  let g:modula2_default_dialect = 'm2r10'
+"  let g:modula2_r10_allow_lowline = 1
+
+
+if exists("b:current_syntax")
+  finish
+endif
+
+" Modula-2 is case sensitive
+syn case match
+
+
+" -----------------------------------------------------------------------------
+" Reserved Words
+" -----------------------------------------------------------------------------
+" Note: MODULE, PROCEDURE and END are defined separately further below
+syn keyword modula2Resword ALIAS AND ARGLIST ARRAY BEGIN CASE CONST COPY DEFINITION
+syn keyword modula2Resword DIV DO ELSE ELSIF EXIT FOR FROM GENLIB IF IMPLEMENTATION
+syn keyword modula2Resword IMPORT IN LOOP MOD NEW NOT OF OPAQUE OR POINTER READ
+syn keyword modula2Resword RECORD RELEASE REPEAT RETAIN RETURN SET THEN TO TYPE
+syn keyword modula2Resword UNTIL VAR WHILE WRITE YIELD
+
+
+" -----------------------------------------------------------------------------
+" Schroedinger's Tokens
+" -----------------------------------------------------------------------------
+syn keyword modula2SchroedToken CAPACITY COROUTINE LITERAL
+
+
+" -----------------------------------------------------------------------------
+" Builtin Constant Identifiers
+" -----------------------------------------------------------------------------
+syn keyword modula2ConstIdent NIL FALSE TRUE
+
+
+" -----------------------------------------------------------------------------
+" Builtin Type Identifiers
+" -----------------------------------------------------------------------------
+syn keyword modula2TypeIdent BOOLEAN CHAR UNICHAR OCTET
+syn keyword modula2TypeIdent CARDINAL LONGCARD INTEGER LONGINT REAL LONGREAL
+
+
+" -----------------------------------------------------------------------------
+" Builtin Procedure and Function Identifiers
+" -----------------------------------------------------------------------------
+syn keyword modula2ProcIdent APPEND INSERT REMOVE SORT SORTNEW
+syn keyword modula2FuncIdent CHR ORD ODD ABS SGN MIN MAX LOG2 POW2 ENTIER
+syn keyword modula2FuncIdent PRED SUCC PTR COUNT LENGTH
+
+
+" -----------------------------------------------------------------------------
+" Builtin Macro Identifiers
+" -----------------------------------------------------------------------------
+syn keyword modula2MacroIdent NOP TMIN TMAX TSIZE TLIMIT
+
+
+" -----------------------------------------------------------------------------
+" Builtin Primitives
+" -----------------------------------------------------------------------------
+syn keyword modula2PrimitiveIdent SXF VAL STORE VALUE SEEK SUBSET
+
+
+" -----------------------------------------------------------------------------
+" Unsafe Facilities via Pseudo-Module UNSAFE
+" -----------------------------------------------------------------------------
+syn keyword modula2UnsafeIdent UNSAFE BYTE WORD LONGWORD OCTETSEQ
+syn keyword modula2UnsafeIdent ADD SUB INC DEC SETBIT HALT
+syn keyword modula2UnsafeIdent ADR CAST BIT SHL SHR BWNOT BWAND BWOR
+
+
+" -----------------------------------------------------------------------------
+" Non-Portable Language Extensions
+" -----------------------------------------------------------------------------
+syn keyword modula2NonPortableIdent ASSEMBLER ASM REG
+
+
+" -----------------------------------------------------------------------------
+" User Defined Identifiers
+" -----------------------------------------------------------------------------
+syn match modula2Ident "[a-zA-Z][a-zA-Z0-9]*\(_\)\@!"
+syn match modula2LowLineIdent "[a-zA-Z][a-zA-Z0-9]*\(_[a-zA-Z0-9]\+\)\+"
+
+syn match modula2ReswordDo "\(TO\)\@<!DO"
+syn match modula2ReswordTo "TO\(\sDO\)\@!"
+
+" TODO: support for OpenVMS reswords and identifiers which may include $ and %
+
+
+" -----------------------------------------------------------------------------
+" String Literals
+" -----------------------------------------------------------------------------
+syn region modula2String start=/"/ end=/"/ oneline
+syn region modula2String start="\(^\|\s\|[({=<>&#,]\|\[\)\@<='" end=/'/ oneline
+
+
+" -----------------------------------------------------------------------------
+" Numeric Literals
+" -----------------------------------------------------------------------------
+syn match modula2Base2Num "0b[01]\+\('[01]\+\)*"
+syn match modula2Base16Num "0[ux][0-9A-F]\+\('[0-9A-F]\+\)*"
+
+"| *** VMSCRIPT BUG ALERT ***
+"| The regular expression below causes errors when split into separate strings
+"|
+"| syn match modula2Base10Num
+"|   \ "\(\(0[bux]\@!\|[1-9]\)[0-9]*\('[0-9]\+\)*\)" .
+"|   \ "\(\.[0-9]\+\('[0-9]\+\)*\(e[+-]\?[0-9]\+\('[0-9]\+\)*\)\?\)\?"
+"|
+"| E475: Invalid argument: modula2Base10Num "\(\(0[bux]\@!\|[1-9]\)[0-9]*\('[0-9]\+\)*\)"
+"|  . "\(\.[0-9]\+\('[0-9]\+\)*\(e[+-]\?[0-9]\+\('[0-9]\+\)*\)\?\)\?"
+"|
+"| However, the same regular expression works just fine as a sole string.
+"|
+"| As a consequence, we have no choice but to put it all into a single line
+"| which greatly diminishes readability and thereby increases the opportunity
+"| for error during maintenance. Ideally, regular expressions should be split
+"| into small human readable pieces with interleaved comments that explain
+"| precisely what each piece is doing.  Vimscript imposes poor design. :-(
+
+syn match modula2Base10Num
+  \ "\(\(0[bux]\@!\|[1-9]\)[0-9]*\('[0-9]\+\)*\)\(\.[0-9]\+\('[0-9]\+\)*\(e[+-]\?[0-9]\+\('[0-9]\+\)*\)\?\)\?"
+
+
+" -----------------------------------------------------------------------------
+" Punctuation
+" -----------------------------------------------------------------------------
+syn match modula2Punctuation
+  \ "\.\|[,:;]\|\*\|[/+-]\|\#\|[=<>&]\|\^\|\[\|\]\|(\(\*\)\@!\|[){}]"
+
+
+" -----------------------------------------------------------------------------
+" Pragmas
+" -----------------------------------------------------------------------------
+syn region modula2Pragma start="<\*" end="\*>"
+  \ contains = modula2PragmaKey, modula2TechDebtPragma
+syn keyword modula2PragmaKey contained MSG IF ELSIF ELSE END INLINE NOINLINE OUT
+syn keyword modula2PragmaKey contained GENERATED ENCODING ALIGN PADBITS NORETURN
+syn keyword modula2PragmaKey contained PURITY SINGLEASSIGN LOWLATENCY VOLATILE
+syn keyword modula2PragmaKey contained FORWARD ADDR FFI FFIDENT
+
+syn match modula2DialectTag "(\*!m2r10\(+[a-z0-9]\+\)\?\*)"
+
+
+" -----------------------------------------------------------------------------
+" Line Comments
+" -----------------------------------------------------------------------------
+syn region modula2Comment start=/^!/ end=/$/ oneline
+
+
+" -----------------------------------------------------------------------------
+" Block Comments
+" -----------------------------------------------------------------------------
+syn region modula2Comment
+  \ start="\(END\s\)\@<!(\*\(!m2r10\(+[a-z0-9]\+\)\?\*)\)\@!" end="\*)"
+  \ contains = modula2Comment, modula2CommentKey, modula2TechDebtMarker
+
+syn match modula2CommentKey
+  \ "[Aa]uthor[s]\?\|[Cc]opyright\|[Ll]icense\|[Ss]ynopsis" contained
+syn match modula2CommentKey
+  \ "\([Pp]re\|[Pp]ost\|[Ee]rror\)\-condition[s]\?:" contained
+
+
+" -----------------------------------------------------------------------------
+" Block Statement Tails
+" -----------------------------------------------------------------------------
+syn match modula2ReswordEnd
+  \ "END" nextgroup = modula2StmtTailComment skipwhite
+syn match modula2StmtTailComment
+  \ "(\*\s\(IF\|CASE\|FOR\|LOOP\|WHILE\)\s\*)" contained
+
+
+" -----------------------------------------------------------------------------
+" Technical Debt Markers
+" -----------------------------------------------------------------------------
+syn match modula2ToDoHeader "TO DO"
+
+syn match modula2ToDoTail
+  \ "END\(\s(\*\sTO DO\s\*)\)\@=" nextgroup = modula2ToDoTailComment skipwhite
+syntax match modula2ToDoTailComment "(\*\sTO DO\s\*)" contained
+
+" contained within pragma
+syn keyword modula2TechDebtPragma contained DEPRECATED
+
+" contained within comment
+syn keyword modula2TechDebtMarker contained FIXME
+
+
+" -----------------------------------------------------------------------------
+" Disabled Code Sections
+" -----------------------------------------------------------------------------
+syn region modula2DisabledCode start="^?<" end="^>?"
+
+
+" -----------------------------------------------------------------------------
+" Headers
+" -----------------------------------------------------------------------------
+" !!! this section must be second last !!!
+
+" module header
+syn match modula2ModuleHeader
+  \ "\(MODULE\|BLUEPRINT\)\( [A-Z][a-zA-Z0-9]*\)\?"
+  \ contains = modula2ReswordModule, modula2ReswordBlueprint, modula2ModuleIdent
+
+syn match modula2ModuleIdent
+  \ "[A-Z][a-zA-Z0-9]*" contained
+
+syn match modula2ModuleTail
+  \ "END [A-Z][a-zA-Z0-9]*\.$"
+  \ contains = modula2ReswordEnd, modula2ModuleIdent, modula2Punctuation
+
+" procedure, sole occurrence
+syn match modula2ProcedureHeader
+  \ "PROCEDURE\(\s\[\|\s[a-zA-Z]\)\@!" contains = modula2ReswordProcedure
+
+" procedure header
+syn match modula2ProcedureHeader
+  \ "PROCEDURE [a-zA-Z][a-zA-Z0-9]*\(_[a-zA-Z0-9]\+\)*"
+  \ contains = modula2ReswordProcedure,
+  \ modula2ProcedureIdent, modula2ProcedureLowlineIdent, modula2IllegalChar, modula2IllegalIdent
+
+" procedure binding to operator
+syn match modula2ProcedureHeader
+  \ "PROCEDURE \[[+-\*/\\=<>]\] [a-zA-Z][a-zA-Z0-9]*\(_[a-zA-Z0-9]\+\)*"
+  \ contains = modula2ReswordProcedure, modula2Punctuation,
+  \ modula2ProcedureIdent, modula2ProcedureLowlineIdent, modula2IllegalChar, modula2IllegalIdent
+
+" procedure binding to builtin
+syn match modula2ProcedureHeader
+  \ "PROCEDURE \[[A-Z]\+\(:\([#\*,]\|++\|--\)\?\)\?\] [a-zA-Z][a-zA-Z0-9]*\(_[a-zA-Z0-9]\+\)*"
+  \ contains = modula2ReswordProcedure,
+  \ modula2Punctuation, modula2Resword, modula2SchroedToken,
+  \ modula2ProcIdent, modula2FuncIdent, modula2PrimitiveIdent,
+  \ modula2ProcedureIdent, modula2ProcedureLowlineIdent, modula2IllegalChar, modula2IllegalIdent
+
+syn match modula2ProcedureIdent
+  \ "\([a-zA-Z]\)\([a-zA-Z0-9]*\)" contained
+
+syn match modula2ProcedureLowlineIdent
+  \ "[a-zA-Z][a-zA-Z0-9]*\(_[a-zA-Z0-9]\+\)\+" contained
+
+syn match modula2ProcedureTail
+  \ "END [a-zA-Z][a-zA-Z0-9]*\(_[a-zA-Z0-9]\+\)*;$"
+  \ contains = modula2ReswordEnd,
+  \ modula2ProcedureIdent, modula2ProcedureLowLineIdent,
+  \ modula2Punctuation, modula2IllegalChar, modula2IllegalIdent
+
+syn keyword modula2ReswordModule contained MODULE
+syn keyword modula2ReswordBlueprint contained BLUEPRINT
+syn keyword modula2ReswordProcedure contained PROCEDURE
+syn keyword modula2ReswordEnd contained END
+
+
+" -----------------------------------------------------------------------------
+" Illegal Symbols
+" -----------------------------------------------------------------------------
+" !!! this section must be last !!!
+
+" any '`' '~' '@' '$' '%'
+syn match modula2IllegalChar "[`~@$%]"
+
+" any solitary sequence of '_'
+syn match modula2IllegalChar "\<_\+\>"
+
+" any '?' at start of line if not followed by '<'
+syn match modula2IllegalChar "^?\(<\)\@!"
+
+" any '?' not following '>' at start of line
+syn match modula2IllegalChar "\(\(^>\)\|\(^\)\)\@<!?"
+
+" any identifiers with leading occurrences of '_'
+syn match modula2IllegalIdent "_\+[a-zA-Z][a-zA-Z0-9]*\(_\+[a-zA-Z0-9]*\)*"
+
+" any identifiers containing consecutive occurences of '_'
+syn match modula2IllegalIdent
+  \ "[a-zA-Z][a-zA-Z0-9]*\(_[a-zA-Z0-9]\+\)*\(__\+[a-zA-Z0-9]\+\(_[a-zA-Z0-9]\+\)*\)\+"
+
+" any identifiers with trailing occurrences of '_'
+syn match modula2IllegalIdent "[a-zA-Z][a-zA-Z0-9]*\(_\+[a-zA-Z0-9]\+\)*_\+\>"
+
+
+" -----------------------------------------------------------------------------
+" Define Rendering Styles
+" -----------------------------------------------------------------------------
+
+" highlight default link modula2PredefIdentStyle Keyword
+" highlight default link modula2ConstIdentStyle modula2PredefIdentStyle
+" highlight default link modula2TypeIdentStyle modula2PredefIdentStyle
+" highlight default link modula2ProcIdentStyle modula2PredefIdentStyle
+" highlight default link modula2FuncIdentStyle modula2PredefIdentStyle
+" highlight default link modula2MacroIdentStyle modula2PredefIdentStyle
+
+highlight default link modula2ConstIdentStyle Constant
+highlight default link modula2TypeIdentStyle Type
+highlight default link modula2ProcIdentStyle Function
+highlight default link modula2FuncIdentStyle Function
+highlight default link modula2MacroIdentStyle Function
+highlight default link modula2PrimitiveIdentStyle Function
+highlight default link modula2UnsafeIdentStyle Question
+highlight default link modula2NonPortableIdentStyle Question
+highlight default link modula2StringLiteralStyle String
+highlight default link modula2CommentStyle Comment
+highlight default link modula2PragmaStyle PreProc
+highlight default link modula2PragmaKeyStyle PreProc
+highlight default link modula2DialectTagStyle SpecialComment
+highlight default link modula2TechDebtMarkerStyle SpecialComment
+highlight default link modula2ReswordStyle Keyword
+highlight default link modula2HeaderIdentStyle Function
+highlight default link modula2UserDefIdentStyle Normal
+highlight default link modula2NumericLiteralStyle Number
+highlight default link modula2PunctuationStyle Delimiter
+highlight default link modula2CommentKeyStyle SpecialComment
+highlight default link modula2DisabledCodeStyle NonText
+
+
+" -----------------------------------------------------------------------------
+" Assign Rendering Styles
+" -----------------------------------------------------------------------------
+
+" headers
+highlight default link modula2ModuleIdent modula2HeaderIdentStyle
+highlight default link modula2ProcedureIdent modula2HeaderIdentStyle
+highlight default link modula2ModuleHeader modula2HeaderIdentStyle
+highlight default link modula2ModuleTail Normal
+highlight default link modula2ProcedureHeader Normal
+highlight default link modula2ProcedureTail Normal
+
+" lowline identifiers are rendered as errors if g:modula2_r10_allow_lowline is unset
+if exists("g:modula2_r10_allow_lowline")
+  if g:modula2_r10_allow_lowline != 0
+    highlight default link modula2ProcedureLowlineIdent modula2HeaderIdentStyle
+  else
+    highlight default link modula2ProcedureLowlineIdent Error
+  endif
+else
+  highlight default link modula2ProcedureLowlineIdent modula2HeaderIdentStyle
+endif
+
+" reserved words
+highlight default link modula2Resword modula2ReswordStyle
+highlight default link modula2ReswordModule modula2ReswordStyle
+highlight default link modula2ReswordProcedure modula2ReswordStyle
+highlight default link modula2ReswordEnd modula2ReswordStyle
+highlight default link modula2ReswordDo modula2ReswordStyle
+highlight default link modula2ReswordTo modula2ReswordStyle
+highlight default link modula2SchroedToken modula2ReswordStyle
+
+" predefined identifiers
+highlight default link modula2ConstIdent modula2ConstIdentStyle
+highlight default link modula2TypeIdent modula2TypeIdentStyle
+highlight default link modula2ProcIdent modula2ProcIdentStyle
+highlight default link modula2FuncIdent modula2FuncIdentStyle
+highlight default link modula2MacroIdent modula2MacroIdentStyle
+highlight default link modula2PrimitiveIdent modula2PrimitiveIdentStyle
+
+" unsafe and non-portable identifiers
+highlight default link modula2UnsafeIdent modula2UnsafeIdentStyle
+highlight default link modula2NonPortableIdent modula2NonPortableIdentStyle
+
+" user defined identifiers
+highlight default link modula2Ident modula2UserDefIdentStyle
+
+" lowline identifiers are rendered as errors if g:modula2_r10_allow_lowline is unset
+if exists("g:modula2_r10_allow_lowline")
+  if g:modula2_r10_allow_lowline != 0
+    highlight default link modula2LowLineIdent modula2UserDefIdentStyle
+  else
+    highlight default link modula2LowLineIdent Error
+  endif
+else
+  highlight default link modula2LowLineIdent modula2UserDefIdentStyle
+endif
+
+" literals
+highlight default link modula2String modula2StringLiteralStyle
+highlight default link modula2Base2Num modula2NumericLiteralStyle
+highlight default link modula2Base10Num modula2NumericLiteralStyle
+highlight default link modula2Base16Num modula2NumericLiteralStyle
+
+" punctuation
+highlight default link modula2Punctuation modula2PunctuationStyle
+
+" pragmas
+highlight default link modula2Pragma modula2PragmaStyle
+highlight default link modula2PragmaKey modula2PragmaKeyStyle
+highlight default link modula2DialectTag modula2DialectTagStyle
+
+" comments
+highlight default link modula2Comment modula2CommentStyle
+highlight default link modula2CommentKey modula2CommentKeyStyle
+highlight default link modula2ToDoTailComment modula2CommentStyle
+highlight default link modula2StmtTailComment modula2CommentStyle
+
+" technical debt markers
+highlight default link modula2ToDoHeader modula2TechDebtMarkerStyle
+highlight default link modula2ToDoTail modula2TechDebtMarkerStyle
+highlight default link modula2TechDebtPragma modula2TechDebtMarkerStyle
+
+" disabled code
+highlight default link modula2DisabledCode modula2DisabledCodeStyle
+
+" illegal symbols
+highlight default link modula2IllegalChar Error
+highlight default link modula2IllegalIdent Error
+
+
+let b:current_syntax = "modula2"
+
+" vim: ts=4
+
+" END OF FILE
diff --git a/test/old/testdir/test_filetype.vim b/test/old/testdir/test_filetype.vim
index 9f493bb792..50e60de484 100644
--- a/test/old/testdir/test_filetype.vim
+++ b/test/old/testdir/test_filetype.vim
@@ -424,7 +424,6 @@ func s:GetFilenameChecks() abort
     \ 'mma': ['file.nb'],
     \ 'mmp': ['file.mmp'],
     \ 'modconf': ['/etc/modules.conf', '/etc/modules', '/etc/conf.modules', '/etc/modprobe.file', 'any/etc/conf.modules', 'any/etc/modprobe.file', 'any/etc/modules', 'any/etc/modules.conf'],
-    \ 'modula2': ['file.m2', 'file.mi'],
     \ 'modula3': ['file.m3', 'file.mg', 'file.i3', 'file.ig', 'file.lm3'],
     \ 'monk': ['file.isc', 'file.monk', 'file.ssc', 'file.tsc'],
     \ 'moo': ['file.moo'],
@@ -1550,13 +1549,16 @@ func Test_mod_file()
   call writefile(['IMPLEMENTATION MODULE Module2Mod;'], 'modfile.MOD')
   split modfile.MOD
   call assert_equal('modula2', &filetype)
+  call assert_equal('pim', b:modula2.dialect)
   bwipe!
 
   " Modula-2 with comment and empty lines prior MODULE
   call writefile(['', '(* with',  ' comment *)', '', 'MODULE Module2Mod;'], 'modfile.MOD')
   split modfile.MOD
   call assert_equal('modula2', &filetype)
+  call assert_equal('pim', b:modula2.dialect)
   bwipe!
+
   call delete('modfile.MOD')
 
   " LambdaProlog module
@@ -2284,4 +2286,38 @@ func Test_i_file()
   filetype off
 endfunc
 
+func Test_def_file()
+  filetype on
+
+  call writefile(['this is the fallback'], 'Xfile.def', 'D')
+  split Xfile.def
+  call assert_equal('def', &filetype)
+  bwipe!
+
+  " Test dist#ft#FTdef()
+
+  let g:filetype_def = 'modula2'
+  split Xfile.def
+  call assert_equal('modula2', &filetype)
+  call assert_equal('pim', b:modula2.dialect)
+  bwipe!
+  unlet g:filetype_def
+
+  " Modula-2
+
+  call writefile(['(* a Modula-2 comment *)'], 'Xfile.def')
+  split Xfile.def
+  call assert_equal('modula2', &filetype)
+  call assert_equal('pim', b:modula2.dialect)
+  bwipe!
+
+  call writefile(['IMPLEMENTATION MODULE Module2Mod;'], 'Xfile.def')
+  split Xfile.def
+  call assert_equal('modula2', &filetype)
+  call assert_equal('pim', b:modula2.dialect)
+  bwipe!
+
+  filetype off
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab