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>

1 files changed, 31 insertions, 0 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: