Re: TimeSignature with note in denominator

[David Kastrup]

Carl Sorensen <c_sorensen@byu.edu> writes:

> On 11/13/21, 1:09 PM, "David Kastrup" <dak@gnu.org> wrote:
>
>     Carl Sorensen <c_sorensen@byu.edu> writes:
>     
>     > I have not been a strong contributor to this thread.  And I have not
>     > been a strong advocate for the time signatures with a notehead in the
>     > denominator.  I think all of those time signatures can be expressed
>     > just as well as a compound meter.
>     >
>     > HOWEVER,
>     >
>     > In looking at this, is seems the lexer (and the propery
>     > timeSignatureFraction) are not semantically correct.
>     >
>     > Although the time signature looks like a fraction, it is not.  A
>     > fraction has numbers in the denominator and the numerator (and
>     > strictly speaking, a fraction properly has integers in the numerator
>     > and denominator -- if they are not integers, it's a quotient, not a
>     > fraction, IIUC).  And the time signature has an integer in the
>     > "numerator" and a duration in the "denominator".
>     
>     I don't get your point.  Are you objecting to the use of the word
>     "fraction" or what is your complaint?  The representation is a pair of
>     integers, not a rational number, so \time 4/4 and \time 2/2 are
>     different things.
>
> Yes.  The numerical representation of traditional time signatures is a
> pair of integers.  But the "numerator" can be any integer.  While the
> "denominator" can also be any integer, it doesn't really represent an
> integer.  It represents a duration; a fraction of a whole note.

A time signature is written with numbers, not durations.

>     > I'm not sure it is worth the work to get semantically correct, but
>     > semantically, \time 4/4 should not be a fraction of two integers; it
>     > should be a pair of a count and a duration.
>     >
>     > And if we had semantically correct time signature entry,
>     
>     Here you are talking about the _entry_ rather than the names used
>     internally.  So what is your beef with the _entry_?
>
> I can't enter \time 3/2., even though 2. is a valid duration.

    3
But 2. is not a valid time signature.

>     > Kieren's wish for a different display for the duration would be
>     > relatively straightforward,
>     
>     Here you make a statement that somehow your objection to entry or
>     internal namings, once recognised, magically makes other possibilities
>     appear.  I don't see it.
>
> If the entry is a duration,

But it isn't and has never been.

> and timeSignatureFraction is a pair consisting of an integer and
> duration, then it's trivial to get the current output by using
> ly:duration->string for the bottom number on the time signature, and
> it's also trivial to get a note representing the duration as the
> bottom element of the time signature.

There is
          /*
            Todo: should make typecheck?

            OTOH, Tristan Keuris writes 8/20 in his Intermezzi.
          */

in lily/time-signature-engraver.cc

Your refactoring desire does not seem to leave room for that.

-- 
David Kastrup