unparser
Generate equivalent source for ASTs from whitequarks parser.
This library is able to reproduce 100% of ruby 1.9, 2.0 and 2.1 syntax. Including its own source code.
It serves well for mutant mutators and the in-memory vendoring for self hosting.
Usage
require 'unparser'
Unparser.unparse(your_ast) # => "the code"
To preserve the comments from the source:
require 'parser/current'
require 'unparser'
ast, comments = Parser::CurrentRuby.parse_with_comments(your_source)
Unparser.unparse(ast, comments) # => "the code # with comments"
Equivalent vs identical:
require 'unparser'
code = <<-RUBY
%w(foo bar)
RUBY
node = Parser::CurrentRuby.parse(code)
generated = Unparser.unparse(node) # ["foo", "bar"], NOT %w(foo bar) !
code == generated # false, not identical code
Parser::CurrentRuby.parse(generated) == node # true, but identical AST
Summary: unparser does not reproduce your source! It produces equivalent source.
Testing:
Unparser currently successfully round trips almost all ruby code around. Using MRI-2.0.0. If there is a non round trippable example that is NOT subjected to known Limitations. please report a bug.
On CI unparser is currently tested against rubyspec with minor excludes.
Limitations:
Source parsed with magic encoding headers other than UTF-8 and that have literal strings. where parts can be represented in UTF-8 will fail to get reproduced.
Please note: If you are on 1.9.3 or any 1.9 mode ruby and use UTF-8 encoded source via the magic encoding header: Unparser does not reproduce these.
A fix might be possible and requires some guessing or parser metadata the raw AST does not carry.
Example:
Original-Source:
# -*- encoding: binary -*-
"\x98\x76\xAB\xCD\x45\x32\xEF\x01\x01\x23\x45\x67\x89\xAB\xCD\xEF"
Original-AST:
(str "\x98v\xAB\xCDE2\xEF\x01\x01#Eg\x89\xAB\xCD\xEF")
Generated-Source:
"\x98v\xAB\xCDE2\xEF\x01\x01#Eg\x89\xAB\xCD\xEF"
Generated-AST:
(str "\x98v\xAB\xCDE2\xEF\u0001\u0001#Eg\x89\xAB\xCD\xEF")
Diff:
@@ -1,2 +1,2 @@
-(str "\x98v\xAB\xCDE2\xEF\x01\x01#Eg\x89\xAB\xCD\xEF")
+(str "\x98v\xAB\xCDE2\xEF\u0001\u0001#Eg\x89\xAB\xCD\xEF")
Installation
Install the gem unparser
via your prefered method.
People
- Markus Schirp (mbj) Author
- Trent Ogren (misfo) Adding comment reproduction
Contributing
- Fork the project.
- Make your feature addition or bug fix.
- Add tests for it. This is important so I don't break it in a future version unintentionally.
- Commit, do not mess with Rakefile or version (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)
- Send me a pull request. Bonus points for topic branches.
License
See LICENSE file.