Install ErRuby on Mac

Install ErRuby which is Erlang's implementation for Ruby.
The purpose is to learn the structure of Ruby implementation.
MRI(Matz Ruby Implementation = CRuby) is too big to understand entire structure.

Mac: 10.9.4
Ruby: 2.2.3p173

Install

Install reading this page.
https://github.com/johnlinvc/erruby

$ brew install erlang rebar

$ cd $GIT_DIR/
$ git clone https://github.com/johnlinvc/erruby

$ rbenv local 2.2.3

$ view Gemfile

$ bundle install

I got warnings, and an error, created directory at first.
And still have an error.

$ view rebar.config

$ rebar get-deps
WARN:  Expected /Users/jun.aruga/git/erruby/deps/erlport to be a raw dependency directory, but no directory found.
==> erruby (get-deps)
WARN:  Expected /Users/jun.aruga/git/erruby/deps/erlport to be a raw dependency directory, but no directory found.
Pulling erlport from {git,"git@github.com:hdima/erlport.git",
                          {branch,"master"}}
Cloning into 'erlport'...
Permission denied (publickey).
fatal: Could not read from remote repository.

$ mkdir deps/erlport

$ rebar get-deps
...
Same kind of error.
...

I added SSH keys to github, this PC's key was not registered to github.

$ ssh -T git@github.com
Hi junaruga! You've successfully authenticated, but GitHub does not provide shell access.
https://help.github.com/articles/error-permission-denied-publickey/

Success for following command.

$ rebar get-deps

$ rebar compile

$ echo $?
0

Error happened.

$ ./erruby rb_test/hello_world.rb
error undef
[{ruby,start,[],[]},{erruby,start_ruby,0,[{file,"src/erruby.erl"},{line,66}]},{erruby,eruby,1,[{file,"src/erruby.erl"},{line,36}]},{erruby,main,1,[{file,"src/erruby.erl"},{line,26}]},{escript,run,2,[{file,"escript.erl"},{line,757}]},{escript,start,1,[{file,"escript.erl"},{line,277}]},{init,start_it,1,[]},{init,start_em,1,[]}]

Check HEAD commit hash of develop branch.

$ git branch
* develop
$ git rev-parse HEAD
776d0abc2b92f4d38e2145358152d2a07dcbc04f

Finally I tried from $ git clone https://github.com/johnlinvc/erruby, again.
And success to print "hello world"!

$ ./erruby rb_test/hello_world.rb
hello world

Read source

I am interested in the parse logic from ruby code to AST.

erruby
  -> ebin/erruby.beam
    -> ebin/erruby.app
      -> src/erruby.erl
        -> function main
          -> function parse_ast (Create ast from ruby code)
            -> rb_src/erruby.rb def parse
              -> ErlPort::AstMapping.parse(src)
                -> Gemfile, gem 'erlport-ast_mapping', github: "johnlinvc/erlport-ast_mapping"
                  -> https://github.com/johnlinvc/erlport-ast_mapping
                    -> erlport-ast_mapping/lib/erlport/ast_mapping.rb def parse
                      -> ::Parser::CurrentRuby.parse(src)
                        -> https://github.com/whitequark/parser

Run AST part.

erruby
  -> ebin/erruby.beam
    -> ebin/erruby.app
      -> src/erruby.erl
        -> function main
          -> function erruby_vm:eval_ast (Run AST)
            -> src/erruby_vm.erl function eval_ast(AST)
              -> There are seveval eval_ast functions, called recursively.

There are debug options to check the behavior.

$ ./erruby -d rb_test/hello_world.rb
debug level 1: send
debug level 1: Ast: undefined
debug level 1: Ast: puts
debug level 1: Ast: {ast,type,str,children,[<<"hello world">>]}
hello world

$ ./erruby -d 2 rb_test/hello_world.rb
debug level 2: input file name rb_test/hello_world.rb
debug level 2: input args
debug level 1: send
debug level 1: Ast: undefined
debug level 1: Ast: puts
debug level 1: Ast: {ast,type,str,children,[<<"hello world">>]}
debug level 2: finding method:puts
 in State:#{consts => #{'FalseClass' => <0.39.0>,'NilClass' => <0.36.0>,'TrueClass' => <0.38.0>},
            ivars => #{},
            methods => #{'==' => #Fun<erruby_object.4.93324764>,
              inspect => #Fun<erruby_object.2.93324764>,
              puts => #Fun<erruby_object.0.93324764>,
              self => #Fun<erruby_object.1.93324764>,
              to_s => #Fun<erruby_object.3.93324764>},
            properties => #{},
            self => <0.33.0>}
hello world