Re: 2.21 note definition change

[David Kastrup]

David Kastrup <dak@gnu.org> writes:

> Paul Scott <waterhorse@ultrasw.com> writes:
>
>> On 6/23/20 2:23 PM, David Kastrup wrote:
>>> Paul Scott <waterhorse@ultrasw.com> writes:
>>>
>>>> The 1st argument for note is now a duration rather than a string.
>>>>
>>>> I had some scheme definitions which were variations on \tempo.
>>>>
>>>> I used (string?) for this value before.  What is the new scheme
>>>> equivalent?  (duration?)
>>> ly:duration?
>>
>> Thank you, David.
>>
>> I believe I had tried that.
>>
>> Here's my MWE which hopefully will show someone what dumb mistake I'm
>> making:
>>
>> \version "2.21.2"
>>
>> #(define-markup-command (notetest layout props dur) (ly:duration?)
>>   interpret-markup layout props
>>   (markup
>>    #:note dur #up
>>  ))
>>
>> {
>>   \tempo \markup{ Allegro \notetest #4 }
>>   c'1
>> }
>>
>> Thank you,
>
> Several.  Is there a reason you use the markup macro rather than
> #{ \markup ... #} ?  The latter can do the same but is more
> straightforward to use when not familiar with Scheme syntax, and you
> really make it appear like you aren't.
>
> You write interpret-markup ... instead of (interpret-markup ...) .  In
> Scheme, every pair of paren conveys meaning.  They aren't syntactic
> sugar which you can add or remove.
>
> Then you write #up in Scheme.  # in Scheme introduces specially parsed
> expressions, such as #(...) for literal vectors, or #{ ... #} for
> embedded LilyPond or #t or #f for true and false boolean literals.
>
> And both LilyPond and (Guile) Scheme are case sensitive: you cannot swap
> up and UP.
>
> In LilyPond expressions, you'd write #UP here, with # escaping from
> LilyPond mode into Scheme mode, and UP being the Scheme expression in
> question.  If you are doing copy-and-paste from documentation, only
> LilyPond mode will work sensibly, so my recommendation of using
> #{ \markup ... #} here.
>
> Then you call \notetest #4 where 4 is a number, not a duration.  To get
> into LilyPond parsing mode for an argument of a markup function, one can
> use braces (I am not sure this feature will persist to 2.22 in this
> form, but 2.21 is a development version).  So you need to write { 4 }
> here in order to get a duration.  In a way, that is syntactic sugar for
> writing ##{ 4 #} but the latter looks uglier.

Forgot the example.

\version "2.21.2"

#(define-markup-command (notetest layout props dur) (ly:duration?)
  (interpret-markup layout props
                    (markup #:note dur UP)))

{
  \tempo \markup{ Allegro \notetest {4} }
  c'1
}


-- 
David Kastrup