Re: Add lilypond version predicates/operators (issue 317270043 by address@hidden)

[dak]

On 2017/02/14 15:46:20, git wrote:
> On 2017/02/14 15:37:35, pwm wrote:
> > On 2017/02/14 15:15:07, git wrote:
> > > I like this more because it's more of a typical procedure
invocation.
> > > I think I'll create a new patch with this and a simplified
calculate-version
> > > (that doesn't accept string lists)
> >
> > Well, having the procedure as the first argument might be more
scheme-ish?
> >
> > Maybe best would be to have a "version-compare" function that
compares two
> > version lists using a procedure.  Then define "ly:version?" so it
calls
> > "version-compare" with the current LilyPond version (to handle the
primary use
> > case).  The "version-compare" function could be David's looping
function, but
> > modified so that it took two version lists and a procedure as
arguments.

> This is what I'm currently working on.
> However, I found an issue in David's suggestion, namely the
> (op 0 0) ;; return #t iff op includes equality
> line.
> This makes the function return #t when comparing with = and one list
shortened
> Try e.g. (ly:version? = 2 16)
> This returns #t because in the third iteration when the reference
version has
> run out of elements it compares 0 to 0.

Have you actually tried it?  If your major version is not actually 2.16,
you will not even _get_ into a third iteration.

https://codereview.appspot.com/317270043/