Re: Dedicated functions for negative predicate tests (issue 345190043 by address@hidden)

[dak]

On 2019/02/08 17:05:46, Valentin Villenave wrote:
> On 2019/02/08 16:41:06, dak wrote:
> > For what?

> For making some functions ever so slightly less cumbersome to type and
to read.
> But I’m gathering from your question that you’ve never felt any need
for it :-)

(not (null? xxx)) vs (not-null? xxx) is not really much of an advantage.

(filter (lambda (x) (not null? x)) ...) vs (filter null? ...) would be
an advantage but in that case pair? can often quite well replace
not-null? .

> Since you’re complaining about LilyPond-specific functions not handled
by Guile,
> what about assoc-get? From what I gather, this remains entirely bound
to our
> codebase?

And I plan to at one time let it deal with more than just pairs in a
list, also allowing hashtables as members (and likely tails) and likely
vectors.

So it's actually good if it is under our control.

> BTW, just out of curiosity: when you say "let’s not make things opaque
to the
> Scheme compiler", are you referring to something already existing with
Guile 1.8
> and which I’ve (very conceivably) never heard about, or only to the
JIT-bytecode
> feature that’s been introduced with v2.0?

It's not just bytecode but also optimization of the intermediate
language.  Not sure to which degree Guile 1.8 does that.  Admittedly
Guile-1.8 supported a completely hare-brained hack I tried for
reimplementing local-eval using call-with-current-continuation, and that
hack would likely not have worked in a multiple-pass system of
compilation.

https://codereview.appspot.com/345190043/