Fix various issues with highlighting in C and C++ lexers (#1069)

Before this commit:

1. `void foo();` without a space before ";" would not highlight
   correctly;
2. `else if()` would not highlight correctly in certain contexts;
3. an error in a function definition or declaration had the potential
   to cause incorrect highlighting further down in the file.

The commit also contains minor changes to the Objective-C lexer to fix
regressions caused by dependencies on the broken behaviour of the C
lexer that has been fixed.

This fixes #879 and #1009.

lib/rouge/lexers/c.rb

@@ -106,7 +106,7 @@ def self.builtins
         rule /\d+[lu]*/i, Num::Integer
         rule %r(\*/), Error
         rule %r([~!%^&*+=\|?:<>/-]), Operator
-        rule /[()\[\],.]/, Punctuation
+        rule /[()\[\],.;]/, Punctuation
         rule /\bcase\b/, Keyword, :case
         rule /(?:true|false|NULL)\b/, Name::Builtin
         rule id do |m|
@@ -133,47 +133,24 @@ def self.builtins
 
       state :root do
         mixin :expr_whitespace
-
-        # functions
         rule %r(
           ([\w*\s]+?[\s*]) # return arguments
           (#{id})          # function name
           (\s*\([^;]*?\))  # signature
-          (#{ws})({)         # open brace
+          (#{ws}?)({|;)    # open brace or semicolon
         )mx do |m|
           # TODO: do this better.
           recurse m[1]
           token Name::Function, m[2]
           recurse m[3]
           recurse m[4]
           token Punctuation, m[5]
-          push :function
-        end
-
-        # function declarations
-        rule %r(
-          ([\w*\s]+?[\s*]) # return arguments
-          (#{id})          # function name
-          (\s*\([^;]*?\))  # signature
-          (#{ws})(;)       # semicolon
-        )mx do |m|
-          # TODO: do this better.
-          recurse m[1]
-          token Name::Function, m[2]
-          recurse m[3]
-          recurse m[4]
-          token Punctuation, m[5]
-          push :statement
+          if m[5] == ?{
+            push :function
+          end
         end
-
-        rule(//) { push :statement }
-      end
-
-      state :statement do
-        rule /;/, Punctuation, :pop!
-        mixin :expr_whitespace
+        rule /\{/, Punctuation, :function
         mixin :statements
-        rule /[{}]/, Punctuation
       end
 
       state :function do

lib/rouge/lexers/objective_c.rb

@@ -44,15 +44,8 @@ def self.builtins
         rule /@\d+l?/, Num::Integer
         rule /\bin\b/, Keyword
 
-        rule /@(?:interface|implementation)\b/ do
-          token Keyword
-          goto :classname
-        end
-
-        rule /@(?:class|protocol)\b/ do
-          token Keyword
-          goto :forward_classname
-        end
+        rule /@(?:interface|implementation)\b/, Keyword, :classname
+        rule /@(?:class|protocol)\b/, Keyword, :forward_classname
 
         rule /@([[:alnum:]]+)/ do |m|
           if self.class.at_keywords.include? m[1]
@@ -80,7 +73,7 @@ def self.builtins
         rule /\{/, Punctuation, :pop!
         rule /;/, Error
 
-        mixin :statement
+        mixin :statements
       end
 
       state :message do

spec/visual/samples/c

@@ -31,9 +31,6 @@ static int not_a_comment();
 
 #macro
 
-
-/* Bug #277: C function prototype syntax highlighting broken if space before semicolon */
-
 void foo() ;
 
 void foo() {
@@ -45,6 +42,14 @@ void foo2(void)
     /* nothing */
 }
 
+/* Broken declarations should not break subsequent highlighting */
+
+void foo() {
+    if(x) {
+    } else if(y) {
+      puts("foo")
+    }
+  }
 
 /* Execute compiled code */