Re: Music-function "arguments" - help

[Urs Liska]

Am 07.12.18 um 11:07 schrieb Urs Liska:
> Am 07.12.18 um 10:55 schrieb mansouraoun:
> > i wrote the code in raw and it's somehow not displayed in my message
> > Here it is
> >
> > dynx =
> > #(define-music-function
> >       (parser location X-offset)
> >       (number?)
> >     #{
> >       \once\override DynamicText.X-offset = #X-offset
> >     #})
> >
> > Mansour
> As David said: if you use the development version (currently 2.19.82) 
> you can simplify this by skipping "parser location":
>
>   ...
>   #(define-music-function (X-offset)(number?)
>   ...


And while we're at it:

As David also pointed out, the *naming* of such variables is arbitrary, 
it's just their order/position. "parser" and "location" are arguments 
that the LilyPond parser (in 2.18) *implicitly* passes to a music 
function because *sometimes* a music function has the need to access 
either the current LilyPond parser or the "location" (the place in the 
input file from where the function was called). But since the vast 
majority of functions does *not* need them it is needlessly verbose 
having to write them for each and every music function. So two 
procedures, *parser* and *location* were at some point added to LilyPond 
that can be called from within a music function, if it should actually 
need one of these values (to *invoke* a procedure it has to be enclosed 
in parentheses like

  (display (*location*))

For the function you are currently interested in this is of absolutely 
no interest, but I thought to point it out since you were irritated by 
the function arguments in the first place, so it may be interesting to know.

Best
Urs

> Urs
>
>
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