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

[Daniel Shahaf <d.s@daniel.shahaf.name>]

Daniel Shahaf wrote on Fri, 03 Jul 2020 22:23 +0000:
> > 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).  
> 
> FWIW, I thought at first reading that that second sentence referred to
> the `tt(-)' in the parameter expansion flags, not to the one in the
> input data.  I'd never have expected "-" or "-foo" to be considered an
> integer in the first place, just like "" and "foo" aren't considered integers.
> 
> Incidentally, should "+42" be sorted as an integer?  Right now it isn't.

The following patch addresses the first issue and documents "+42" as a
possible future extension.

Cheers,

Daniel


diff --git a/Doc/Zsh/expn.yo b/Doc/Zsh/expn.yo
index 41ad967b2..21ecf9d6e 100644
--- a/Doc/Zsh/expn.yo
+++ b/Doc/Zsh/expn.yo
@@ -1092,15 +1092,18 @@ Convert all letters in the result to lower case.
 item(tt(n))(
 Sort decimal integers numerically; if the first differing
 characters of two test strings are not digits, sorting
-is lexical.   Integers with more initial zeroes
-are sorted before those with fewer or none.  Hence the array `tt(foo1 foo02
+is lexical.  `tt(+)' and `tt(-)' are not treated specially; they are treated as
+any other non-digit.  Integers with more initial zeroes
+are sorted before those with fewer or none.  Hence the array `tt(foo+24 foo1 foo02
 foo2 foo3 foo20 foo23)' is sorted into the order shown.
 May be combined with `tt(i)' or `tt(O)'.
 )
 item(tt(-))(
 As tt(n), but a leading minus sign indicates a negative decimal
-integer.  A `tt(-)' not followed by an integer does not trigger
+integer.  A leading minus sign not followed by an integer does not trigger
 numeric sorting.
+Note that `tt(+)' signs are not handled specially (this may change in the
+future).
 )
 item(tt(o))(
 Sort the resulting words in ascending order; if this appears on its