Re: \tuplet and \tupletSpan to replace \times and tupletSpannerDuration (issue 7094044)

[dak]

On 2013/01/12 12:54:25, Ian Hulin (gmail) wrote:
> This LGTM, but with one really big question: do we really still need
\tupletSpan
> at all?

It is for setting a default.  If you have a back-and-forth between
tuplets and full notes (which is essentially the case for which there
has been substantial clamor for \triplet as a "shorthand" for \tuplet
3/2), then it might save typing.  I am not sure that the saved typing is
worth having a non-local side-effect in the form of a context property,
but \triplet did not strike me as all that necessary either.

> The start point for this work was to make "easy triplets and tuplets",
i.e. make
> handling of all the triplets and *uplets less daunting and a bit more
readable
> by humans.

> Here is the NR example for tupletSpannerDuration and \times:
> >
> > {
> >   \set tupletSpannerDuration = #(ly:make-moment 1 4)
> >   \times 2/3 { c8 c c c c c }
> > }
> >

Ugly.

> I think using this property was working round the restriction we had
in the
> language at the time in that we couldn't use optional parameters to
music
> functions.

At that time one could not use durations as a "native" parameter to
music functions at all.  But that is more or less a red herring: at that
time, a _lot_ of functionality was just implemented in the parser
instead of using music functions, and if there had been sufficient
pressure for putting an optional duration with a \times command, that
syntax would have ended up in the parser, anyway.

Come to think of it, \times _was_ already hardwired in the parser
because of the 2/3 parsing and was only turned into a music function in
version 2.15.17, when I made LilyPond fractions have a Scheme
representation.

> I really think that unless someone can come up with a really strong
case that
> \tupletSpannerDuration is needed for backwards-compatibility we don't
need to
> provide \tupletSpan.  It was my attempt at covering all the bases in
the
> doc-string for \tupletSpan that convinced me. (See below).

Well, it might have been stupid of me to make a user-understandable
syntax and then special-case a geeky value like 1*0 into it.  I can
offer two cleaner syntactic alternatives:

\tupletSpan \default

\tupletSpanOff

Since unsetting the property will let any setting in a parenting context
shine through, \tupletSpan \default is not unintuitive.  However, it is
longer to write.


https://codereview.appspot.com/7094044/diff/2001/ly/music-functions-init.ly
> File ly/music-functions-init.ly (right):


https://codereview.appspot.com/7094044/diff/2001/ly/music-functions-init.ly#newcode1365
> ly/music-functions-init.ly:1365: tuplets are being subdivided.  To
unset, use a
> zero duration like
> tuplets specified by the current \tuplet command are to be subdivided.
 To
> unset, use a zero duration like @samp{1*0}. Doing this will ensure the
spanner
> for the music on the current \tuplet command spans all the music,
rather than
> the value set to any prior \tupletSpan call.

I think we can agree that we'd rather want a different command or the
\default solution to avoid this technobabble.  That was bad thinking on
my part.

Either that, or scrap the property altogether.  But there would not be a
good convert-ly rule for that course, and the feature is quite likely to
have seen use.

Of course, we can also just leave the property in place and provide no
user-level command for setting it.  But I think even when discouraging
its use, a separate command with a readable presentation will lead to
more readable upconverted scores.

https://codereview.appspot.com/7094044/