Re: Question (define and set!)

[David Kastrup]

Jean Abou Samra <address@hidden> writes:

> Hi,
>
> Why do you often find constructs similar to this one in LilyPond's source?
>
> midi.scm line 26:
>
> (define-session-public absolute-volume-alist '())
> (set! absolute-volume-alist (append absolute-volume-alist etc.))
>
> line 72:
>
> (define instrument-names-alist '())
> (set! instrument-names-alist ...
>
> Is there any difference with (define-session-public
> absolute-volume-alist '(...)) ? I suspect there is one since this is 
> frequent but I can't figure out what the purpose is here.

I don't see that it is frequent.  You'll find it mostly in scm/midi.scm
and if you use git blame on that, you'll find that this style in this
file significantly precedes the introduction of define-session.

You'd have to ask Han-Wen and Jan for their respective motivations here.

-- 
David Kastrup