Re: mmrest-of-length and partial measures/time chnages

[Urs Liska]

Hi Jan-Peter,


Am 12.12.2016 um 09:47 schrieb Jan-Peter Voigt:
> Hi Urs,
>
> this is a problem, I also had to deal with once in a while.
> As it is no daily problem, I hacked it as needed, but did build a
> generic solution yet.
> But it might be doable, *if* the music is "complete" and has a
> \partial command in it, which is
> #(make-music 'PartialSet 'duration (ly:make-duration 2))
> so one can fetch that music-expression and build a rest with that
> duration.

Thank you for this, which is basically a confirmation of what I was
afraid of ;-)

> In my hacks, I usually used a command which receives pre- and
> post-music expressions (e.g. the needed rests) and decreased the
> duration for the multi-measure-rest accordingly.
>
> If there is a \partial, you will need a function, that translates an
> arbitrary duration to a reasonable sequence of rests. \partial 4 is
> easy, but \partial 2.. or whatever needs special handling also
> regarding timesig.
>
> A command \multimeasureRest <pre> <music> <post> should be doable.

Unfortunately this won't be sufficient as it wouldn't allow for time
changes within the music.
So it seems I'll have to go the way to parse the actual music expression
for time and partial elements and construct the rest from that. I assume
I'd have to split the original music expression in a list of expressions
and create one mmrest for each.

However, I think this would actually warrant a proper solution, i.e. a
command like e.g. mmrest-of-section that can be applied to arbitrary
music expressions and should be added to LilyPond.
The question is: should this actually be an additional function or
should I update mmrest-of-length itself? (of course within such a new
function one could make good use of the existing mmrest-of-length
functionality for the individual sections).

Urs

>
> HTH
> Best
> Jan-Peter
>
>
> Am 12.12.2016 um 09:24 schrieb Urs Liska:
>> Hi all,
>>
>> I have a set-up where pausing sections in a part can be handled by
>> automatically inserting multimeasure rests whose length is determined by
>> a meta variable for the sections.
>>
>> As a MWE this looks like this:
>>
>> \version "2.19.52"
>>
>> sectionOne = {
>>   c,1 |
>>   c,1
>> }
>>
>> {
>>   #(mmrest-of-length sectionOne)
>> }
>>
>> which nicely prints a staff with two measures of rest.
>>
>> However, when the referenced variable starts with (or actually contains)
>> a partial measure, LilyPond gets confused:
>>
>> sectionTwo = {
>>   \partial 8
>>   c'8 |
>>   c'1 |
>>   c'1
>> }
>>
>> {
>>   #(mmrest-of-length sectionTwo)
>> }
>>
>> Of course the multi-measure rest now is 17/8 long but doesn't know about
>> the partial and consequently gives me barcheck errors and wrong output.
>>
>> The same is true when the referenced variable contains music in other
>> than 4/4 time signature because mmrest-of-length by default seems to
>> produce 4/4 rests.
>> I can't simply add a \time command in front of the mmrest because this
>> is actually a complex set-up where the variables are retrieved from
>> previously parsed music expressions.
>>
>> So my question is: is there a reliable and more or less convenient way
>> to produce a "rest" part/section from a referenced section, regardless
>> of what's in there. I think basically there are two approaches:
>> a)
>> analyse the music expression for partials and time changes
>> b)
>> copying the music but replace everything with rests.
>>
>> Any pointers would be appreciated
>>
>> Best
>> Urs
>>
>>
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>
>
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