Module: Sass::Callbacks

Included in:
Plugin::Compiler
Defined in:
lib/sass/callbacks.rb

Overview

A lightweight infrastructure for defining and running callbacks. Callbacks are defined using #define_callback at the class level, and called using run_#{name} at the instance level.

Clients can add callbacks by calling the generated on_#{name} method, and passing in a block that's run when the callback is activated.

Examples:

Define a callback

class Munger
  extend Sass::Callbacks
  define_callback :string_munged

  def munge(str)
    res = str.gsub(/[a-z]/, '\1\1')
    run_string_munged str, res
    res
  end
end

Use a callback

m = Munger.new
m.on_string_munged {|str, res| puts "#{str} was munged into #{res}!"}
m.munge "bar" #=> bar was munged into bbaarr!

Defined Under Namespace

Modules: InstanceMethods

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.extended(base)

Automatically includes InstanceMethods when something extends this module.

Parameters:

  • base (Module) 


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# File 'lib/sass/callbacks.rb', line 30

def self.extended(base)
  base.send(:include, InstanceMethods)
end

Instance Method Details

#define_callback(name) (protected)

This method returns an undefined value.

Define a callback with the given name. This will define an on_#{name} method that registers a block, and a run_#{name} method that runs that block (optionall with some arguments).

Parameters:

  • name (Symbol) —

    The name of the callback



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# File 'lib/sass/callbacks.rb', line 51

def define_callback(name)
  class_eval <<RUBY, __FILE__, __LINE__ + 1
def on_#{name}(&block)
  @_sass_callbacks = {} unless defined? @_sass_callbacks
  (@_sass_callbacks[#{name.inspect}] ||= []) << block
end

def run_#{name}(*args)
  return unless defined? @_sass_callbacks
  return unless @_sass_callbacks[#{name.inspect}]
  @_sass_callbacks[#{name.inspect}].each {|c| c[*args]}
end
private :run_#{name}
RUBY
end