[Go] Fix compiler directive syntax patterns

This adds line and export directive syntax patterns and generalises the
//go:name pattern for use in other contexts such as linter directives. It
also fixes //go:name matching to avoid matching invalid directive comments.

Go/Go.sublime-syntax

@@ -79,6 +79,15 @@ variables:
   # functions and types.
   ident: \b(?!{{keyword}})[[:alpha:]_][[:alnum:]_]*\b
 
+  # Directive comment key.
+  directive: \b[[:alpha:]_][[:alnum:]_]*\b
+
+  # Line directive comment key.
+  line_directive: (line) ([a-zA-Z0-9. :]*(?::[0-9]+){1,2})
+
+  # Cgo export and gccgo extern directive.
+  export_directive: (export|extern) ({{ident}})
+
   # Single line only
   inline_comment: /[*](?:[^*]|[*](?!/))*[*]/
 
@@ -118,12 +127,18 @@ contexts:
     #
     # //go:some_directive arg0 arg1 ...
     #
+    # These have been adopted outside the gc compiler for use in linting
+    # directives and pragmas for other compiler suites where they take the
+    # more generalised form of:
+    #
+    # //namespace:some_directive ...
+    #
     # They're not part of the language spec, may not be recognized by some Go
     # compilers, and may stop working in future releases. Therefore,
     # highlighting them as compiler pragmas could be misleading. We scope them
     # as plain comments by default, and add some detailed meta scopes for
     # enterprising users wishing to add more color.
-    - match: (//)(go)(:)({{ident}})?
+    - match: (//)([a-z]+)(:)({{directive}}(?:.*)){1,}
       captures:
         1: punctuation.definition.comment.go
         2: meta.keyword.annotation.go
@@ -138,6 +153,54 @@ contexts:
         - match: $
           set: pop-line-comment
 
+    # Go also has line renumbering; line directives specify the source
+    # position for the character immediately following the comment as
+    # having come from the specified file, line and column. Both single
+    # line and block comment line directives are valid.
+    - match: (//){{line_directive}}$
+      captures:
+        1: punctuation.definition.comment.go
+        2: meta.keyword.annotation.go
+        3: meta.variable.function.go
+      push:
+        - meta_scope: meta.annotation.go comment.line.go
+        - match: \S+
+          scope: meta.variable.parameter.go
+        # End the annotation scope at EOL, but stretch the comment scope
+        # indefinitely to the right.
+        - match: $
+          set: pop-line-comment
+
+    - match: (/\*){{line_directive}}(\*/)
+      captures:
+        1: punctuation.definition.comment.go
+        2: meta.keyword.annotation.go
+        3: meta.variable.function.go
+        4: punctuation.definition.comment.go
+      push:
+        - meta_scope: meta.annotation.go comment.block.go
+        - match: \S+
+          scope: meta.variable.parameter.go
+        # End the annotation scope at EOL, but stretch the comment scope
+        # indefinitely to the right.
+        - match: $
+          set: pop-line-comment
+
+    # Finally, Cgo and gccgo have directives for exporting functions to C.
+    - match: (//){{export_directive}}$
+      captures:
+        1: punctuation.definition.comment.go
+        2: meta.keyword.annotation.go
+        3: meta.variable.function.go
+      push:
+        - meta_scope: meta.annotation.go comment.line.go
+        - match: \S+
+          scope: meta.variable.parameter.go
+        # End the annotation scope at EOL, but stretch the comment scope
+        # indefinitely to the right.
+        - match: $
+          set: pop-line-comment
+
     # Line comment
     - match: //
       scope: punctuation.definition.comment.go

Go/syntax_test_go.go

@@ -56,20 +56,91 @@ You may have to disable Go-specific linters when working on this file.
     //go
 // ^ -comment -punctuation
 //  ^^ punctuation.definition.comment.go
-//  ^^^^^ comment.line.go -meta.annotation
+//  ^^^^ comment.line.go -meta.annotation
 
     //go:
-// ^ -comment -meta -punctuation
+// ^ -comment -punctuation
 //  ^^ punctuation.definition.comment.go
-//  ^^^^^ meta.annotation.go comment.line.go
-//       ^ comment.line.go -meta.annotation
+//  ^^^^^ comment.line.go -meta.annotation
 
     //go:generate one two three
 // ^ -comment -meta -punctuation
 //  ^^ punctuation.definition.comment.go
 //  ^^^^^^^^^^^^^^^^^^^^^^^^^^^ meta.annotation.go comment.line.go
 //                             ^ comment.line.go -meta.annotation
 
+    //lint:ignore U1000 Reason.
+// ^ -comment -meta -punctuation
+//  ^^ punctuation.definition.comment.go
+//  ^^^^^^^^^^^^^^^^^^^^^^^^^^^ meta.annotation.go comment.line.go
+//                             ^ comment.line.go -meta.annotation
+
+    //lint:file-ignore Reason.
+// ^ -comment -meta -punctuation
+//  ^^ punctuation.definition.comment.go
+//  ^^^^^^^^^^^^^^^^^^^^^^^^^^ meta.annotation.go comment.line.go
+//                            ^ comment.line.go -meta.annotation
+
+    //line :10
+// ^ -comment -meta -punctuation
+//  ^^ punctuation.definition.comment.go
+//  ^^^^^^^^^^ meta.annotation.go comment.line.go
+//            ^ comment.line.go -meta.annotation
+
+    //line file.rl:10
+// ^ -comment -meta -punctuation
+//  ^^ punctuation.definition.comment.go
+//  ^^^^^^^^^^^^^^^^^ meta.annotation.go comment.line.go
+//                   ^ comment.line.go -meta.annotation
+
+    //line file.rl:100:10
+// ^ -comment -meta -punctuation
+//  ^^ punctuation.definition.comment.go
+//  ^^^^^^^^^^^^^^^^^^^^^ meta.annotation.go comment.line.go
+//                       ^ comment.line.go -meta.annotation
+
+    /*line :10*/
+// ^ -comment
+//  ^^^^^^^^^^^^ meta.annotation.go comment.block.go
+//              ^ -comment.block.go -meta.annotation
+
+    /*line file.rl:10*/
+// ^ -comment
+//  ^^^^^^^^^^^^^^^^^^^ meta.annotation.go comment.block.go
+//                     ^ -comment.block.go -meta.annotation
+
+    /*line file.rl:100:10*/
+// ^ -comment
+//  ^^^^^^^^^^^^^^^^^^^^^^^ meta.annotation.go comment.block.go
+//                         ^ -comment.block.go -meta.annotation
+
+    /*line :10 */
+// ^ -comment
+//  ^^^^^^^^^^^^^ comment.block.go -meta.annotation
+//               ^ -comment
+
+    /*line file.rl:10 */
+// ^ -comment
+//  ^^^^^^^^^^^^^^^^^^^^ comment.block.go -meta.annotation
+//                      ^ -comment
+
+    /*line file.rl:100:10 */
+// ^ -comment
+//  ^^^^^^^^^^^^^^^^^^^^^^^^ comment.block.go -meta.annotation
+//                          ^ -comment
+
+    //export myfunc
+// ^ -comment -meta -punctuation
+//  ^^ punctuation.definition.comment.go
+//  ^^^^^^^^^^^^^^^ meta.annotation.go comment.line.go
+//                 ^ comment.line.go -meta.annotation
+
+    //extern myfunc
+// ^ -comment -meta -punctuation
+//  ^^ punctuation.definition.comment.go
+//  ^^^^^^^^^^^^^^^ meta.annotation.go comment.line.go
+//                 ^ comment.line.go -meta.annotation
+
 
 // # Imports