Added detection for the new M (aka MUMPS) language.

lib/linguist/blob_helper.rb

@@ -457,6 +457,9 @@ module Linguist
     # * Leading function keyword
     # * "%" comments
     #
+    # M heuristics:
+    # * ";" comments
+    #
     # Returns a Language.
     def guess_m_language
       # Objective-C keywords
@@ -471,6 +474,10 @@ module Linguist
       elsif lines.grep(/^%/).any?
         Language['Matlab']
 
+      # M comment
+      elsif lines.grep(/^[ \t]*;/).any?
+        Language['M']
+
       # Fallback to Objective-C, don't want any Matlab false positives
       else
         Language['Objective-C']

lib/linguist/languages.yml

@@ -627,6 +627,14 @@ Lua:
   - .lua
   - .nse
 
+M:
+  type: programming
+  lexer: Text only
+  aliases:
+  - mumps
+  extensions:
+  - .m
+
 Makefile:
   extensions:
   - .mak