Generate equivalent source for ASTs from whitequarks parser.
The following constraints apply:
- No support for macruby extensions
- Only support for the modern AST format
- Only support for Ruby >= 2.5
It serves well for mutant mutators and the in-memory vendoring for self hosting, and other tooling.
While unparser is in the
0.x versions its public API can change any moment.
I recommend to use
~> 0.x.y style version constraints that should give the best mileage.
require 'parser/current' require 'unparser' ast = Unparser.parse('your(ruby(code))') Unparser.unparse(ast) # => 'your(ruby(code))'
To preserve the comments from the source:
require 'parser/current' require 'unparser' ast, comments = Unparser.parse_with_comments('your(ruby(code)) # with comments') Unparser.unparse(ast, comments) # => 'your(ruby(code)) # with comments'
Passing in manually constructed AST:
require 'parser/current' require 'unparser' module YourHelper def s(type, *children) Parser::AST::Node.new(type, children) end end include YourHelper node = s(:def, :foo, s(:args, s(:arg, :x) ), s(:send, s(:lvar, :x), :+, s(:int, 3) ) ) Unparser.unparse(node) # => "def foo(x)\n x + 3\nend"
Note: DO NOT attempt to pass in nodes generated via
AST::Sexp#s, these ones return
AST::Node instances, unparser needs
Equivalent vs identical:
require 'unparser' node = Unparser.parse(<<~'RUBY') %w[foo bar] RUBY generated = Unparser.unparse(node) # ["foo", "bar"], NOT %w[foo bar] ! code == generated # false, not identical code Unparser.parse(generated) == node # true, but identical AST
Summary: unparser does not reproduce your source! It produces equivalent source.
Unparser currently successfully round trips almost all ruby code around. Using MRI-2.5.x. 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.
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.
A fix is possible as with latest updates the parser gem carries the information.
# -*- encoding: binary -*- "\x98\x76\xAB\xCD\x45\x32\xEF\x01\x01\x23\x45\x67\x89\xAB\xCD\xEF"
@@ -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")
Install the gem
unparser via your prefered method.
Various people contributed to this repository. See Contributors.
- 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.
See LICENSE file.