fix numeric-only strings for legend - fix #100

CHANGES

@@ -2,6 +2,7 @@
   packaging. Fixes #98.
 - fixes for Windows (#89)
 - use terminal "dumb" if probing shows "unknown" (#66)
+- fix numeric-only strings for legend (#100) - thanks @d-lamb for report
 
 2.024 2023-03-30
 - Add Alien::Gnuplot as a configure-time dependency. Fixes #92 - thanks @zmughal

lib/PDL/Graphics/Gnuplot.pm

@@ -5466,7 +5466,7 @@ $_pOHInputs = {
     ## one-line list (can also be boolean)
     'l' => sub { return undef unless(defined $_[1]);
 		 return "" unless(length($_[1]));                                 # false value yields false
-		 return $_[1] if( (!ref($_[1])) && "$_[1]" =~ m/^\s*\-?\d+\s*$/); # nonzero integers yield true
+		 return [$_[1]] if( (!ref($_[1])) && "$_[1]" =~ m/^\s*\-?\d+\s*$/); # nonzero integers yield true
 		 # Not setting a boolean value - it's a list (or a trivial list).
 		 return $_[1] if ref $_[1] eq 'ARRAY';
 		 # anything that's not an array ref (and not a number) gets put in the array

t/plot.t

@@ -825,11 +825,15 @@ $b = pdl(1,4,9,16,25)->sqrt;  # 1,2,3,4,5
 
 $w->plot(with=>'lines',$a,{binary=>1});
 $w->close;
-
 @lines = do { open my $fh, "<", $testoutput or die "$testoutput: $!"; <$fh> };
 isnt $lines[12], '';
 like substr($lines[12],20,40), qr/^\s+$/, "NaN makes a blank in a plot";
 
+$w->restart;
+eval {$w->plot(with=>'lines',legend=>'456',$b)};
+is $@, '', "can use numeric-only strings for legend"; # GH#100
+$w->close;
+
 $w->restart;
 $w->plot(with=>'lines',$b,{binary=>1});
 $w->close;