From: Hans Aberg <haberg-1@telia.com>
To: Andy Wingo <wingo@pobox.com>
Cc: guile-devel <guile-devel@gnu.org>
Subject: Re: summary: lilypond, lambda, and local-eval
Date: Thu, 15 Dec 2011 17:52:03 +0100 [thread overview]
Message-ID: <9365BFAA-2F16-438E-A6B7-7C2AE4E48B08@telia.com> (raw)
In-Reply-To: <87r506uodd.fsf@pobox.com>
On 15 Dec 2011, at 11:21, Andy Wingo wrote:
> The "delayed evaluation" thread is a bit long and confusing, so I would
> like to try to summarize it.
>
> Lilypond has a way to embed Lilypond code in Scheme, and Scheme code in
> Lilypond code. The former uses a reader macro, #{#}. The latter uses
> specially-marked variables and expressions, specifically, those preceded
> by $ or #.
...
> It took some time for everyone to understand the problem. In the end,
> there were four workable possibilities.
>
> 1) Keep using closures.
When doing a parser on top of Guile, I noticed one must first build an unevaluated closure, and only thereafter call the evaluator. Scheme has some restrictions forcing this, for example, the lambda cannot appear as a free symbol, though it is possible in Guile using scm_sym_lambda.
It might be useful with a variation of scm_eval_string() that only parses and builds the closure, but not calls the evaluator.
Hans
next prev parent reply other threads:[~2011-12-15 16:52 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-15 10:21 summary: lilypond, lambda, and local-eval Andy Wingo
2011-12-15 14:46 ` David Kastrup
2011-12-15 16:52 ` Hans Aberg [this message]
2011-12-15 17:24 ` David Kastrup
2011-12-15 17:52 ` Hans Aberg
2011-12-16 7:35 ` Mark H Weaver
2011-12-16 8:08 ` Mark H Weaver
2011-12-16 8:49 ` Mark H Weaver
2011-12-16 9:16 ` David Kastrup
2011-12-18 7:11 ` Mark H Weaver
2011-12-18 11:27 ` Andy Wingo
2011-12-18 15:32 ` Noah Lavine
2011-12-18 16:19 ` David Kastrup
2011-12-18 21:24 ` Noah Lavine
2011-12-19 9:13 ` Mark H Weaver
2012-01-09 14:44 ` David Kastrup
2011-12-16 9:28 ` Andy Wingo
2011-12-16 9:59 ` David Kastrup
2011-12-16 10:33 ` Mark H Weaver
2011-12-16 12:13 ` Hans Aberg
2011-12-16 12:43 ` David Kastrup
2011-12-16 14:57 ` Hans Aberg
2011-12-21 10:32 ` Ian Hulin
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