binding_of_caller

(C) John Mair (banisterfiend) 2012

Retrieve the binding of a method's caller in MRI (>= 2.0.0) and RBX (Rubinius)

The binding_of_caller gem provides the Binding#of_caller method.

Using binding_of_caller we can grab bindings from higher up the call stack and evaluate code in that context. Allows access to bindings arbitrarily far up the call stack, not limited to just the immediate caller.

Recommended for use only in debugging situations. Do not use this in production apps.

Works in MRI Ruby (>= 2.0) and RBX (Rubinius)

• Install the gem: gem install binding_of_caller
• See the source code

Example: Modifying a local inside the caller of a caller

def a
  var = 10
  b
  puts var
end

def b
  c
end

def c
  binding.of_caller(2).eval('var = :hello')
end

a()

# OUTPUT
# => hello

Spinoff project

This project is a spinoff from the Pry REPL project.

Features and limitations

• Works in MRI (>= 2.0.0) and RBX (Rubinius)
• For MRI 1.9.x, use version "~> 0.8" of the gem, which included support for MRI before 2.0.
• Does not work in 1.8.7, but there is a well known (continuation-based) hack to get a Binding#of_caller there.
• There is experimental support for jruby 1.7.x, but it only works in interpreted mode (i.e. use the option -Djruby.compile.mode=OFF or append compile.mode=OFF to your .jrubyrc)

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contact

Problems or questions contact me at github

License

(The MIT License)

Copyright (c) 2012 (John Mair)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.