Re: Trill and nonstandard expressive mark

[Olivier Biot]

On Sat, Jan 5, 2013 at 5:10 PM, David Kastrup <address@hidden> wrote:

Ed Gordijn <address@hidden> writes:

> Hi David,
>> Well, you need _two_ trill starting commands now (though you could
>> likely squeeze <>\startTrillSpan into \SetUpPrall), and you need to
>> spend more attention to detail to the overrides.
>>
>> So you likely contributed more time on this than I did.
>>
> I am still in 2.16 and did try your tweaks but didn't get it ride. I
> know that 2.17 has got a new syntax with dots but converting that to
> the 2.16 style didn't solve it. Here is my code, I don't know what is
> wrong.
>
> \version "2.16.0"
>
>
> beginPrallSpan = {
>
> \tweak #'(bound-details left text) \markup { \fontsize #-5 \musicglyph
> #"accidentals.leftparen" }
>
> \tweak #'(bound-details left stencil-offset) #'(0.02 . -0.65)
>
> \startTrillSpan
>
> }

Well, putting { ... } around it is wrong, for one thing: it turns the
whole into sequential music.

Bingo!

This is the most counterintuitive syntactic element in LilyPond for newcomers (after Scheme). In most programming languages, curly braces are used for grouping commands, in LilyPond curly braces have a double life and can be used in one of their shapes as a shorthand for "define serial music" (as opposed to "define parallel music" which is done with double angle brackets. The double meaning of the curly braces in LilyPond is rather confusing and I still have the impression at times that things seem to work out of sheer luck when using curly braces.

Is this double meaning of curly braces documented somewhere? I did not come across it in the online manuals so far.

Best regards,

Olivier