Module: AttachFunction

Defined in:
lib/attach_function.rb,
lib/attach_function/version.rb

Constant Summary collapse

VERSION = 
"0.1.0"

Instance Method Summary collapse

Instance Method Details

#_receiver_and_message(method_name, function_symbol) ⇒ Object

attach_function defines new methods that are partial applications of a target function where the first argument to the target function gets fixed to self.

The name of the newly defined method will be the basename of the target function (the module path gets stripped) or a user-specified name. The receiver of relatively specified parameter functions will be the current module, if a user-specified name is given and the user-specified name is not the same as the basename of the target function, or the enclosing module, if no-user specified name is provided or if the user-specified name is the same as the basename of the parameter.

Usage:

module MyModule

def function_method1(arg1, arg2); end
def function_method2(arg1); end

module MethodVersions
  extend Attachmethod
  attach_function :function_method1
  attach_function :function_method2
end

See the specs and the example folder for more examples.



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# File 'lib/attach_function.rb', line 26

def _receiver_and_message(method_name, function_symbol)
  #Parse the function symbol to get the receiver and the function's basename
  if function_symbol.match(/(.*)(?:::|\.)([^:.]*)$/)
    receiver, function_method = $1, $2
    receiver = receiver != "" && eval(receiver) || Object
  else
    #No explicit receiver
    function_method = function_symbol
    #If no receiver is specified, send it to self
    receiver = self
    #Can't send to self if method_name == function_method (or it will recurse and crash):
    #   send it to the outer module/class, if there's no outer module, send it to Object
    if (method_name ||= function_method) == function_method
      receiver = self.name
      outer_module = receiver.rpartition('::').first
      receiver = outer_module == "" ? Object : eval(outer_module)
    end
  end
  
  return [ receiver, function_method ]
end

#attach_function(method_name = nil, function_symbol) ⇒ Object 



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# File 'lib/attach_function.rb', line 48

def attach_function(method_name = nil, function_symbol)
  receiver, message = _receiver_and_message(method_name, function_symbol)

  #If no method_name is given, use the basename of the function being attached
  method_name ||= message

  #The core functionality
  define_method method_name do |*args|
    receiver.send(message, self, *args)
  end
end