Class: Module

Inherits:
Object show all
Defined in:
lib/lab42/core/module.rb

Instance Method Summary collapse

Instance Method Details

#memoize(name, by: ->(n){n}) ⇒ Object 



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# File 'lib/lab42/core/module.rb', line 3

def memoize name, by: ->(n){n}
  im = instance_method name
  cache = {}
  mcache = {}
  # Replace method by the memoized version
  #
  remove_method name
  define_method name do |*args, &blk|
    cache[object_id] ||= {}
    mcache[object_id] ||= im.bind self
    key = by.(*args,&blk)

    return cache[object_id][key] if cache[object_id].has_key? key
    rval = mcache[object_id].(*args, &blk)
    cache[object_id][key] = rval
  end
  wm = instance_method name
  # Create a one time wrapper for cache initialization
  remove_method name
  wrapper = ->(*args,&blk) do
    cache[object_id] = {}
    class << self; self end.module_eval do
      define_method name, wm
    end
    result = wm.bind(self).(*args, &blk)
    # reinstall the wrapper
    class << self; self end.module_eval do
      define_method( name, &wrapper )
    end
    result
  end
  define_method( name, &wrapper )
end