From: Mike Gold <mike.gold.4433@...>
Date: 2009-01-14T05:32:09+09:00
Subject: Re: functional programming

Pascal J. Bourguignon wrote:
> Mike Gold <mike.gold.4433@gmail.com> writes:
> 
>> Why is func.call() or func[] or func.() "very useful" compared to
>> func()?  As I mentioned, in every case I've found it to be a
>> hassle, for the reasons previously stated.
> 
> The reason is because Ruby is a lisp-2.  The same name can be used to
> designate both a method and a variable.  So you need two syntaxes, to
> make reference to the method of a name, or to the variable. 

No, that's not the reason.  It is because Ruby allows method invocation 
without parens.  Therefore parens cannot be used to unambiguously 
"dereference" a function.  The case in point is Python,

class X:
  def f(self):
    return "foo"

x = X()
g = x.f
g() #=> "foo"

triple = lambda z: 3*z
triple(2) #=> 6

We all know the Ruby version, but just for good measure --

class X
  def f
    "foo"
  end
end

x = X.new
g = x.method(:f)
g.call #=> "foo"

triple = lambda { |z| 3*z }
triple.call(2) #=> 6

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