From: Robert Klemme <shortcutter@...>
Date: 2009-01-11T02:19:31+09:00
Subject: Re: functional programming

On 10.01.2009 15:50, Mike Gold wrote:
> Brian Candler wrote:
>> Mike Gold wrote:
>>> Pascal was making a simulation of first-class functions in ruby.  The
>>> difference between lambda { } and a real first-class function is quite
>>> profound.
>> For the benefit of this duffer, could you briefly explain the 
>> difference?
> 
> It has already been shown.  You need to make a sincere effort to 
> understand the post to which you replied.  If you did not understand 
> Pascal's post, then ask a question.

Frankly, I find this reply of yours at least unhelpful if not hostile 
(which might just be an effect of brevity).  That question (which was 
quite precise, even contrasting a definition of "first class functions" 
with Ruby's capabilities) actually refers to a statement that you made 
so you could at least point to the explanation you have seen.

 From what I see Pascal creates a DSL that mimics Lisp in Ruby - with 
all the basic functions like cons, car and all the bracketing (which is 
by no means needed for a functional language).  He also contrasts Ruby's 
capabilities with (Common) Lisp's.  But: Lisp is just one functional 
language among many and the fact that expressions are objects in Lisp 
and the special feature of Lisp macros is not mandatory for a functional 
language as far as I can see.

http://en.wikipedia.org/wiki/Functional_programming

So, while we can agree that Ruby != Lisp - and especially Ruby lacks 
Lisp's macros and access to expressions as objects - there is nothing 
that prevents functional programming in Ruby at all.  And you do neither 
need Lisp's syntax for this nor Lisp's macros.

Back to Brian's original question: When reading through Pascal's 
statements in this thread the only thing that I can see so far is that 
Ruby cannot treat arbitrary expressions as objects.  But as I said, this 
does not seem to be a mandatory feature of a functional language.

http://en.wikipedia.org/wiki/First-class_function

I tend to agree with Martin DeMello's statement about the two core 
concepts of functional programming.  The only thing I would add is that 
while programming without side effects might not make sense in Ruby it 
is possible nevertheless.  You pay a price in GC overhead but this is 
irrelevant for answering whether Ruby has functional capabilities.

Regards

	robert

-- 
remember.guy do |as, often| as.you_can - without end