From: Gavin Sinclair <gsinclair@...>
Date: 2004-08-05T00:01:09+09:00
Subject: Re: Macros in Ruby

On Wednesday, August 4, 2004, 10:41:43 PM, Jesse wrote:

>> Jesse Jones wrote:
>> >>Your statement implies that Ruby blocks are
>> >>equivalent to LISP closures, which is untrue.
>> >
>> > As far as I can tell Lisp lambda functions (ie closures) do everything
>> > that Ruby blocks and proc objects do but with cleaner semantics and
>> > fewer artifical distinctions.

Lisp lambda functions *do* do everything that Ruby blocks do.  But
doing is not the same as being.  I wrote that they are not equivalent.
The difference is syntax.  It's an artifical distinction that works
tremendously well in practice at expressing the solution in code.

>> What are some of the differences? I've been away from lisp for a while....

> Between Ruby and Lisp? To tell the truth I'm not entirely sure. The
> pickaxe book does a lousy job explaining the differences between blocks
> and proc objects. I'm still not sure why Ruby needs two concepts when
> Lisp and other languages get by with one. I also don't know why Ruby
> uses that weird yield syntax.

On the one hand you advocate macros to make syntax more expressive; on
the other you advocate rolling everything back into anonymous
functions with no visual distinctions.  *shrug*

Gavin