bug#10132: Help lilypond interleave scheme and lilypond code in guile 2.x

[Andy Wingo <wingo@pobox.com>]

Hi David,

This bug was forked from bug 10099, where David has a longer
explanation.

On Fri 25 Nov 2011 11:37, David Kastrup <dak@gnu.org> writes:

> So much for that.  The next quote is for a totally different issue, the
> availability of local environments and evaluation in them.  Lilypond has
> an input syntax of its own, and it allows interspersing Scheme code. $
> or # switches to the Scheme interpreter (for one sexp) when in Lilypond
> syntax, and #{ ... #} switches to Lilypond inside.

Aaah.  Thanks for this explanation; I had never seen this code before.

Do you use a read-hash-extend reader for #{#} ?

What do you use to parse the lilypond code?  What does it parse to?

I agree that the-environment and local-eval were nice solutions for
this.  In Guile 2.0 it's not as nice for you, because if you implement
another evaluator, you don't get backtraces that are as nice.

> As I said: for this particular application, I have coded a rather
> inelegant and resource-grabbing workaround that really is not going to
> help performance since the intertwined Lilypond interpreter does not
> benefit from precompilation of mostly trivial lambda functions when the
> actual procedure-environment is unlikely to ever reference more than
> five variables.

Understood.  Let's work to find a good solution in 2.0.

Andy
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