Re: How to impose a numeric sort on negative numbers?

[Peter Stephenson <p.w.stephenson@xxxxxxxxxxxx>]

On Thu, 2020-07-02 at 08:46 -0700, Bart Schaefer wrote:
> Peter Stephenson wrote on Wed, 01 Jul 2020 20:42 +0100:
> > > +++ b/Doc/Zsh/expn.yo
> > > @@ -1097,6 +1097,11 @@ are sorted before those with fewer or none.  Hence the array `tt(foo1 foo02
> > >  foo2 foo3 foo20 foo23)' is sorted into the order shown.
> > >  May be combined with `tt(i)' or `tt(O)'.
> > >  )
> > > +item(tt(DASH()))(
> > > +As tt(n), but a leading minus sign indicates a negative decimal
> > > +integer.  A solo `tt(DASH())' not followed by an integer does
> > > +not trigger numeric sorting.
> > > +)
> 
> It might be possible to change this.  For numeric sort, the function
> eltpcmp() in sort.c ignores everything other than digits that compares
> the same in any pair of the strings.  It could recognize a leading
> hyphen as special.

(I've committed it with DASH() turned into -.)

The doc was just to record the fact that I didn't treat a "-" as "-0",
just as a character "-".  That was a deliberate choice --- I'm
assuming the usual case of a numeric sort will have at least one
decimal digit in the part to be sorted and anything else is
just a hyphen (and definitely not a dash).

pws