From: Robert Feldt <feldt@...>
Date: 2002-02-21T16:30:08+09:00
Subject: Re: REBOL vs Ruby

On Thu, 21 Feb 2002, Todd Gillespie wrote:

> Robert Feldt <feldt@ce.chalmers.se> wrote:
> : This is interesting. What do you think of Lisp-style macros? I've only
> : used them very briefly but from my understanding they seem very powerful
> : and can be used to simplify programs (since you can describe your
> : problem/solution in a language dialect tailored to it) and even make them
> : more readable. But its a two-edged sword since the language is no longer
> : "pure"/core so that you (or you-at-a-later-date or your 
> : followers/maintainers etc) must now understand a new dialect (or whole
> : new language) to understand what the program does. 
> 
> If you look at that 'problem' in the larger scope, you see that the same
> tool that lets Lisp programmers write their own variants of Lisp, the
> macro, allows Lisp as a language to evolve quickly.  When a new language
> abstraction of technique comes around (like OO), Lisp can and
> does implement the new idea overnight -- they don't need to step down a
> level for the implementation language, like Ruby must step down to C.  So
> the full power of the language is available for that language's extension.
> 
Yes, thats important.

> As for readability, doesn't every code shop have their own collection of
> in-house hacks and libraries?  Don't you need to understand their API (a
> dialect, if you will) to understand their programs?
> 
You're probably right. I'm coming from a macros-hinders-readability
viewpoint but more and more leaning towards they being important and
powerful while not making a whole lot of difference regarding readability
(readability is more up to how they are used).

> : I've been playing with the idea of introducing macros to Ruby (I
> : guess something in the style of Dylan's hygienic macros or the OOPSLA
> 
> I say, rock on.
> 
Yeah, but this is long-term...

> What do you think about Dylan macros, BTW?  I have heard that Dylan syntax
> is directly convertible to s-expressions, which makes macros either easy
> or possible.  How would you apply them to Ruby?
> 
I guess preprocessor like the Java Syntactic Extender (see Jonathan
Bacrach at MIT) or Avi Bryants ELIDE system. But there are also some ideas
in the new DrScheme/MzScheme environment that needs to be checked
out. Haven't found much documentation on that one yet though.

Regards,

Robert