68 lines
1.9 KiB
Ruby
68 lines
1.9 KiB
Ruby
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module Sass
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# A lightweight infrastructure for defining and running callbacks.
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# Callbacks are defined using \{#define\_callback\} at the class level,
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# and called using `run_#{name}` at the instance level.
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#
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# Clients can add callbacks by calling the generated `on_#{name}` method,
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# and passing in a block that's run when the callback is activated.
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#
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# @example Define a callback
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# class Munger
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# extend Sass::Callbacks
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# define_callback :string_munged
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#
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# def munge(str)
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# res = str.gsub(/[a-z]/, '\1\1')
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# run_string_munged str, res
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# res
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# end
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# end
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#
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# @example Use a callback
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# m = Munger.new
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# m.on_string_munged {|str, res| puts "#{str} was munged into #{res}!"}
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# m.munge "bar" #=> bar was munged into bbaarr!
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module Callbacks
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# Automatically includes {InstanceMethods}
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# when something extends this module.
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#
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# @param base [Module]
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def self.extended(base)
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base.send(:include, InstanceMethods)
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end
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protected
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module InstanceMethods
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# Removes all callbacks registered against this object.
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def clear_callbacks!
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@_sass_callbacks = {}
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end
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end
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# Define a callback with the given name.
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# This will define an `on_#{name}` method
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# that registers a block,
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# and a `run_#{name}` method that runs that block
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# (optionall with some arguments).
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#
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# @param name [Symbol] The name of the callback
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# @return [void]
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def define_callback(name)
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class_eval <<RUBY, __FILE__, __LINE__ + 1
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def on_#{name}(&block)
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@_sass_callbacks = {} unless defined? @_sass_callbacks
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(@_sass_callbacks[#{name.inspect}] ||= []) << block
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end
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def run_#{name}(*args)
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return unless defined? @_sass_callbacks
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return unless @_sass_callbacks[#{name.inspect}]
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@_sass_callbacks[#{name.inspect}].each {|c| c[*args]}
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end
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private :run_#{name}
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RUBY
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end
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end
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end
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