vim-patch:9.1.0505: filetype: Faust files are not recognized (#29426)

Problem:  filetype: Faust files are not recognized
Solution: Detect '*.lib' files as Faust filetype, add detection for
          '*.dsp' files (Faust or Make), remove '*.lib' from Cobol
          filetype (PowerUser64)

closes: vim/vim#14894

aa61b8a908

Co-authored-by: PowerUser64 <blake@blakenorth.net>

runtime/lua/vim/filetype.lua

@@ -281,7 +281,6 @@ local extension = {
   cook = 'cook',
   cmake = 'cmake',
   cmod = 'cmod',
-  lib = 'cobol',
   cob = 'cobol',
   cbl = 'cobol',
   atg = 'coco',
@@ -366,6 +365,7 @@ local extension = {
   gv = 'dot',
   drac = 'dracula',
   drc = 'dracula',
+  dsp = detect.dsp,
   dtd = 'dtd',
   d = detect.dtrace,
   dts = 'dts',
@@ -417,6 +417,7 @@ local extension = {
   fal = 'falcon',
   fan = 'fan',
   fwt = 'fan',
+  lib = 'faust',
   fnl = 'fennel',
   m4gl = 'fgl',
   ['4gl'] = 'fgl',
@@ -666,7 +667,6 @@ local extension = {
   eml = 'mail',
   mk = 'make',
   mak = 'make',
-  dsp = 'make',
   page = 'mallard',
   map = 'map',
   mws = 'maple',

runtime/lua/vim/filetype/detect.lua

@@ -471,6 +471,41 @@ function M.def(_, bufnr)
   return 'def'
 end
 
+--- @type vim.filetype.mapfn
+function M.dsp(path, bufnr)
+  if vim.g.filetype_dsp then
+    return vim.g.filetype_dsp
+  end
+
+  -- Test the filename
+  local file_name = fn.fnamemodify(path, ':t')
+  if file_name:find('^[mM]akefile.*$') then
+    return 'make'
+  end
+
+  -- Test the file contents
+  for _, line in ipairs(getlines(bufnr, 1, 200)) do
+    if
+      findany(line, {
+        -- Check for comment style
+        [[#.*]],
+        -- Check for common lines
+        [[^.*Microsoft Developer Studio Project File.*$]],
+        [[^!MESSAGE This is not a valid makefile\..+$]],
+        -- Check for keywords
+        [[^!(IF,ELSEIF,ENDIF).*$]],
+        -- Check for common assignments
+        [[^SOURCE=.*$]],
+      })
+    then
+      return 'make'
+    end
+  end
+
+  -- Otherwise, assume we have a Faust file
+  return 'faust'
+end
+
 --- @type vim.filetype.mapfn
 function M.e(_, bufnr)
   if vim.g.filetype_euphoria then