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Contents
class Module
# alias_method_chain :foo, :bar produces the following pattern:
#
# alias_method :foo_without_bar, :foo
# alias_method :foo, :foo_with_bar
#
# You will then need to write the foo_with_bar method, which will
# be able to reference foo_without_bar:
#
# def foo_with_bar
# foo_without_bar.map {|x| x + 1 }
# end
#
# Method punctuation (foo? and foo!) will be retained:
#
# alias_method_chain :foo?, :bar will produce:
# foo_without_bar?
# foo_with_bar?
#
# alias_method_chain :foo!, :bar will produce:
# foo_without_bar!
# foo_with_bar!
def alias_method_chain(target, feature)
# Strip out punctuation on predicates or bang methods since
# e.g. target?_without_feature is not a valid method name.
aliased_target, punctuation = target.to_s.sub(/([?!=])$/, ''), $1
yield(aliased_target, punctuation) if block_given?
alias_method "#{aliased_target}_without_#{feature}#{punctuation}", target
alias_method target, "#{aliased_target}_with_#{feature}#{punctuation}"
end
# defines a series of instance variables to be initialized when
# the class is initialized.
#
# For instance, you could create the class Foo:
#
# class Foo
# attr_initialize :bar, :baz
# attr_accessor :bar, :baz
# end
#
# and initialize an instance of the class as follows:
#
# Foo.new(1, 2)
#
# which will create a new Foo object with #bar equal to 1 and #baz
# equal to 2.
#
# Passing a different number of arguments to <tt>new</tt> than you
# passed to attr_initialize will result in an ArgumentError being
# thrown.
def attr_initialize(*attrs)
define_method(:initialize) do |*passed|
raise ArgumentError, "Wrong number of arguments" \
unless attrs.size == passed.size
attrs.each_with_index do |att, i|
instance_variable_set("@#{att}", passed[i])
end
after_initialize if respond_to? :after_initialize
end
end
end
Version data entries
8 entries across 8 versions & 1 rubygems