fix `rake doc` error

using mrbdoc

1 files changed, 6 insertions, 1 deletions

diff --git a/Rakefile b/Rakefile
index 3e03b1096..3021bcc8e 100644
--- a/Rakefile
+++ b/Rakefile
@@ -139,5 +139,10 @@ end
 
 desc 'generate document'
 task :doc do
-  load "#{MRUBY_ROOT}/doc/language/generator.rb"
+  begin
+    sh "mrbdoc"
+  rescue
+    puts "ERROR: To generate documents, you should install yard-mruby gem."
+    puts "  $ gem install yard-mruby"
+  end
 end