Re: Music-function "arguments" - help

[Urs Liska]

Am 7. Dezember 2018 01:46:00 MEZ schrieb David Kastrup <address@hidden>:
>mansouraoun <address@hidden> writes:
>
>> Hello, 
>>
>> I'm still quite a beginner in Lilypond and as much as I'm liking how
>much
>> customisable is its notation capabilities, understanding it is
>driving me
>> crazy because sometimes I can pass more than 4 or 5 hours reading
>manuals
>> and blogposts without reaching a simple answer to a simple question. 
>>
>> My current problem is that I'm learning how to write a music function
>yet
>> there's this mysterious element in it "nth argument" that I can't
>quite
>> understand.
>
>That's just a shorthand for "the argument at position n", a
>generalization of "1st, 2nd, 3rd, 4th, 5th, 6th"...
>
>> I understood all the other elements: the function syntax and how
>> parser and location should be copied literally, the predicate type
>and
>> the body. In this blogpost for example
>> https://lilypondblog.org/2015/04/defining-a-music-function/
>> <https://lilypondblog.org/2015/04/defining-a-music-function/> Urs
>> Liska demonstrates how to create a simple function. In his/her
>> example,

his.

 the nth argument is "my-color". In other examples the
>> argument is "paddingHorizontal", or "paddingVertical", or just
>> "padding". I searched for hours for a list of those arguments to see
>> which one I should use for my need and yet I can't find it anywhere.

Maybe https://scheme-book.ursliska.de can give you further insight. It's far 
from complete and I can't guarantee everything's correct. But I've explicitly 
tried to address  the sort of slow-paced explanations the LilyPond manuals 
can't afford.

Urs


>
>It's not a matter of _using_ an argument but of _naming_ an argument.
>Basically it is arbitrary as long as it has the form of a Scheme
>identifier.  For LilyPond, only the position is interesting, namely
>whether it is 1st, 2nd, 3rd... in the list of the actual arguments when
>calling a music function.
>
>Of course it makes sense to name the argument something that conveys
>meaning to you as the one having to _understand_ the code at a later
>point of time rather than just _execute_ it, but arg1, arg2, arg3,
>arg4... would be totally valid here.
>
>> I just want to create a simple function with an x-offset for dynamic
>> texts but i don't know what is the correct argument for this.
>
>There is no "correct" argument name but x-offset would be fine.