Re: Having trouble understanding optional and variable amount of arguments

[Urs Liska]

Am 08.03.2018 um 16:52 schrieb Urs Liska:
> > @Urs
> > Great! I tested it a bit and it seems to be working as intended.
>
> I have forgotten one thing that I've only halfway completed by now: 
> "accepted" properties without type checking. Currently, if the 
> "strict" flag is set, only keys present in the rules are accepted. But 
> these are also expected, so what's still missing is a way to specify 
> rules as optional so we can filter unknown properties but still have 
> optional ones. I've started on it and I think I know how to do it but 
> I had to leave the computer.

I've pushed another commit to allow "accepted" but "optional" arguments.

Now with the "strict" option unknown properties are still rejected, but 
if a rule has 'opt as its last element the argument is ignored if it is 
not supplied.

This is something to test with:

\version "2.19.80"

\include "oll-core/package.ily"

#(define rules
   `((ind ,number? 5)
     (target ,symbol?)
     (payload)
     (accepted-arg ,fraction? opt)
     (accepted-without-type opt)
     (msg ,string? "No message given")))

testRules =
#(define-void-function (opts) (ly:context-mod?)
   (let ((props (context-mod->props rules #t opts)))
     (pretty-print props)))

\testRules \with {
  msg = "Something"
  unk = "Unknown option"
  target = something
%  accepted-arg = 7/4
%  accepted-without-type = #(ly:make-moment 3/16)
}


Best
Urs