Class: Module

Inherits:
Object show all
Defined in:
lib/epitools/core_ext/module.rb

Instance Method Summary collapse

Instance Method Details

#memoize(*methods) ⇒ Object

Cache (memoize) the result of an instance method the first time it’s called, storing this value in the “@__memoized_#methodname_cache” instance variable, and always return this value on subsequent calls (unless the returned value is nil).



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# File 'lib/epitools/core_ext/module.rb', line 9

def memoize(*methods)
  # alias_method is faster than define_method + old.bind(self).call
  methods.each do |meth|
    alias_method "__memoized__#{meth}", meth
    module_eval <<-EOF
      def #{meth}(*a, &b)
        # assumes the block won't change the result if the args are the same
        (@__memoized_#{meth}_cache ||= {})[a] ||= __memoized__#{meth}(*a, &b)
      end
    EOF
  end
end