Re: \tempo should accept floats

[Simon Albrecht]

Am 28.03.2017 um 17:47 schrieb David Kastrup:
> Urs Liska<address@hidden>  writes:
>
> > As discussion onhttps://github.com/wbsoft/python-ly/pull/90  shows
> > floating point metronome numbers are surely something LilyPond should
> > provide.
> >
> > \tempo 4 = 60.0
> > => error: syntax error, unexpected REAL
> So what do you expect to see here as the markup?  "♩ = 60.0" ?  And for
> \tempo 4 = #190/7
> what do you expect to see here?  "♩ = 12.9"? "♩ = 12.86"?  "♩ = 190/7"?
>
> What for
> \tempo 4 = #(/ 190.0 7) ?
>
> I know how to format an integer.  But I have no way to guess what a
> composer will want to see for some rational or floating-point number.
>
> If LilyPond "should surely provide", the question is_what_  should it
> provide?

I don’t think there is any reason to allow Scheme expressions or usecase 
for doing so. But in modern music it certainly occurs to have metronome 
marks with one or two (maybe more) digits behind the point. So I’d 
consider it sensible to additionally allow _only_ numbers in the form
\tempo 4 = 123.45…
(there should be no point in restricting the number of ‘post-point 
digits’) (sorry, I’m not familiar with English mathematical terminology)

Best, Simon