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module Sass
# 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.
#
# @example 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
#
# @example 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!
module Callbacks
# Automatically includes {InstanceMethods}
# when something extends this module.
#
# @param base [Module]
def self.extended(base)
base.send(:include, InstanceMethods)
end
protected
module InstanceMethods
# Removes all callbacks registered against this object.
def clear_callbacks!
@_sass_callbacks = {}
end
end
# 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).
#
# @param name [Symbol] The name of the callback
# @return [void]
def define_callback(name)
class_eval <<RUBY
def on_#{name}(&block)
@_sass_callbacks ||= {}
(@_sass_callbacks[#{name.inspect}] ||= []) << block
end
def run_#{name}(*args)
return unless @_sass_callbacks
return unless @_sass_callbacks[#{name.inspect}]
@_sass_callbacks[#{name.inspect}].each {|c| c[*args]}
end
private :run_#{name}
RUBY
end
end
end
Version data entries
542 entries across 261 versions & 9 rubygems