Module: Lemo::Ormo::ClassMethods

Defined in:
lib/lemo/ormo.rb

Instance Method Summary collapse

Instance Method Details

#ivar_from(meth) ⇒ Object

provide a legal ivar name from a method name. instance variables can’t have ? ! and other punctuation. Which isn’t handled. Obviously. WARNING meth, meth? and meth! will access the same ivar.



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# File 'lib/lemo/ormo.rb', line 19

def ivar_from( meth )
  :"@#{meth.to_s.delete ILLEGAL_IVAR_CHARS}"
end

#memoed_methods ⇒ Object 



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# File 'lib/lemo/ormo.rb', line 12

def memoed_methods
  @memoed_methods ||= {}
end

#ormo(meth) ⇒ Object Also known as: memo

WARNING race condition if two threads concurrently define the same memo’ed method on the same class. Unlikely, but still.



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# File 'lib/lemo/ormo.rb', line 25

def ormo( meth )
  unbound_previous_method = instance_method meth

  # still doesn't prevent memoisation of methods with an implicit block
  unless unbound_previous_method.parameters.empty?
    raise ArgumentError, "can't memo #{meth} with parameters"
  end

  # keep this for initial calculation, and recalculation
  memoed_methods[meth] = unbound_previous_method
  ivar = ivar_from meth

  # Define the class using instance variable @ syntax, for fastest
  # runtime. Use class_eval to define an instance method, cos self is the
  # class (or singleton class) right now
  class_eval "    def \#{meth}\n      \#{ivar} ||= _memoed_methods[:\#{meth}].bind(self).call\n    end\n  RUBY\n\n  # allow chaining of symbol returned from def\n  meth\nend\n", __FILE__, __LINE__