1 files changed, 10 insertions, 2 deletions
diff --git a/mrbgems/mruby-compiler/mrbgem.rake b/mrbgems/mruby-compiler/mrbgem.rake
index e2a50fb89..9df846abb 100644
--- a/mrbgems/mruby-compiler/mrbgem.rake
+++ b/mrbgems/mruby-compiler/mrbgem.rake
@@ -21,15 +21,23 @@ MRuby::Gem::Specification.new 'mruby-compiler' do |spec|
   # Parser
   file "#{dir}/core/y.tab.c" => ["#{dir}/core/parse.y", lex_def] do |t|
     yacc.run t.name, t.prerequisites.first
-    content = File.read(t.name).gsub(/^#line +\d+ +"\K.*$/){$&.relative_path}
-    File.write(t.name, content)
+    replace_line_directive(t.name)
   end
 
   # Lexical analyzer
   file lex_def => "#{dir}/core/keywords" do |t|
     gperf.run t.name, t.prerequisites.first
+    replace_line_directive(t.name)
   end
 
   file build.libmruby_core_static => core_objs
   build.libmruby << core_objs
+
+  def replace_line_directive(path)
+    content = File.read(path).gsub(%r{
+      ^\#line\s+\d+\s+"\K.*$ |                  # #line directive
+      ^/\*\s+Command-line:.*\s\K\S+(?=\s+\*/$)  # header comment in lex.def
+    }x, &:relative_path)
+    File.write(path, content)
+  end
 end