Re: How to use optional arguments / parameters in a define-markup-command

[Karsten Reincke]

On Mon, 2019-11-04 at 23:45 +0000, Urs Liska wrote:
Dear Urs;

many thanks for your comments and hints! I admire how thoroughly you read other
work and how many time you spend with helping others!
> Hi Karsten,
> 
> 4. November 2019 17:59, "Karsten Reincke" <address@hidden> schrieb:
> [...]
> > Here is a pure scheme / guile solution using lisp association lists (demoed 
> > by
> > using the box example from the extend tutorial). 
> 
> I see one major issue with your approach: it pollutes the namespace with a
> multitude of global variables.
The global variables are only syntactical sugar. I've attached a version which
does not use any global variable any longer

> 
> I don't want to push you towards using openLilyLib ;-) but oll-core includes a
> macro "with-options" (created by Stéfano Troncaro) that allows the 
> modification
> of define-music-function (I'm not sure about markup functions right now) so 
> that
> the function accepts an optional \with { } clause, performs validation against
> mandatory and optional arguments (optionally along with their types) and can
> provide default values - all without necessarily using #(define XXX) and
> creating global variables.
> 
> The code starts here: 
> https://github.com/openlilylib/oll-core/blob/master/internal/options.ily#L245
> 
This is a nice example using the main feature of LISP: even code can become a
parameter and vice versa. But for my purpose, it is too sophisticated. 

> Urs

wit best regards
Karsten
-- 
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