jgraichen/proc-value

Take Smalltalks `#value` to Ruby. Dead easy transparent block usage.

Proc::Value

Proc::Value extends Ruby Objects with a Smalltalk like #value method that always returns the object except when called on a block. In this case the block will be evaluated and the result returned. This allows the transparent exchange of static object with lazy evaluated blocks e.g. for configuration classes.

class Configuration
  def initialize(options)
    @options = options
  end

  def path
  	@options[:path].value.to_s
  end
end

config1 = Configuration.new path: proc { "config/#{RAILS_ENV}/config.yml" }
config2 = Configuration.new path: 'config/config.yml'

config1.path # `path` block will be evaluated here!
             # => "config/development/config.yml"
config2.path # Same code. No extra if statement needed.
             # => "config/config.yml"

Installation

Add this line to your application's Gemfile:

gem 'proc-value'

And then execute:

bundle

Or install it yourself as:

gem install proc-value

Usage

See example above.

You can also use Proc.val(proc_or_object) that does not depend on any injected method and only looks if given object implements a #call method or not.

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Add specs for your feature
4. Add and commit your changes (git commit -am 'Add some feature')
5. Push to the branch (git push origin my-new-feature)
6. Create new Pull Request