Re: Review music functions with pitch and duration arguments

[David Kastrup]

David Kastrup <address@hidden> writes:

>> The Lilypond codebase does not contain such music function arguments I
>> think.  It should actually work to convert them to
>> #(ly:export (ly:make-pitch ...
>> so there is a straightforward (but more likely than not untowardly
>> awkward) migration path.
>>
>> Apart from this change in semantics, this should not cause
>> regressions.

Reconsidering this matter, I have come to the realization that one could
avoid regressions here simply by still permitting Scheme expressions
(and passing them through the specified validator like ly:pitch?).

I see advantages and disadvantages to that approach.

pro: One can provide more and more specially parsed arguments on a
     contingency base without invalidating previous code.
contra:
     This promotes code sloppily interchanging Lilypond and Scheme
     as music function arguments, making music functions behave
     differently from "built-in" Lilypond commands.
     Upgrading code to use ly:export when a predicate becomes specially
     recognized is rather trivial.
Intermediate strategy:
     Allow Scheme for newly converted specially parsed arguments, and
     deprecate and phase out after a while.

Frankly, I consider the bookkeeping for that going a bit overboard for
now.

So my plan would be to just press forward and see whether anybody
complains.

> I put the current state up on Rietveld at
> <URL:http://codereview.appspot.com/4811047>
>
> I don't have a usage example to go with the patch though.  If somebody
> has something nice to offer...

Again: usage example would be welcome.

-- 
David Kastrup