one less src.pos modification

fixed empty =begin/end
[git-p4: depot-paths = "//src/ruby_parser/dev/": change = 5953]

lib/ruby_lexer.rb

@@ -231,7 +231,7 @@ def int_with_base base
   end
 
   def lex_state= o
-    raise "wtf?" unless Symbol === o
+    raise "wtf\?" unless Symbol === o
     @lex_state = o
   end
 
@@ -655,7 +655,7 @@ def yylex # 826 lines
           self.lineno = nil
           c = src.matched
           if c == '#' then
-            src.unread c # ok
+            src.pos -= 1
 
             while src.scan(/\s*#.*(\n+|\z)/) do
               @comments << src.matched.gsub(/^ +#/, '#').gsub(/^ +$/, '')
@@ -723,7 +723,7 @@ def yylex # 826 lines
             self.fix_arg_lex_state
             tok = self.yacc_value = src.matched
             return TOKENS[tok]
-          elsif src.was_begin_of_line and src.scan(/\=begin(?=\s)/) then
+          elsif src.scan(/\=begin(?=\s)/) then
             # @comments << '=' << src.matched
             @comments << src.matched
 

test/test_ruby_parser.rb

@@ -175,6 +175,15 @@ def test_do_bug # TODO: rename
     assert_equal pt, @processor.parse(rb)
   end
 
+  def test_bug_comment_eq_begin
+    rb = "\n\n#\n=begin\nblah\n=end\n\n"
+    pt = nil
+    exp = rb[2..-1]
+
+    assert_equal pt, @processor.parse(rb)
+    assert_equal exp, @processor.lexer.comments
+  end
+
   def test_dstr_evstr
     rb = "\"#\{'a'}#\{b}\""
     pt = s(:dstr, "a", s(:evstr, s(:call, nil, :b, s(:arglist))))