On Wed, Nov 23, 2005 at 08:04:32AM -0800, Peter Scott wrote:
: On Tue, 22 Nov 2005 14:34:12 -0800, Larry Wall wrote:
: > What tipped me over the edge, however, is that I want ^$x back for a unary
: > operator that is short for 0..^$x, that is, the range from 0 to $x - 1. I
: > kept wanting such an operator in revising S09. It also makes it easy to
: > write
: >
: > for ^5 { say } # 0, 1, 2, 3, 4
:
: It seems strange to have a shortcut for 0..$n-1 but no shortcut for 0..$n.
But then you'd usually want 1..$n instead...
: I'm also puzzled that you feel the need to write 0..$n-1 so often; there
: are so many alternatives to fenceposting in P5 that I almost never write
: an expression like that, so why is it cropping up that much in P6?
Couple reasons occur to me offhand. First we're doing away with $#foo.
Second is all the array sizing in P5 is implicit, whereas S9 style
arrays are all about explicit array sizing, and 0..$n-1 comes up all
the time there. But I also am liking the generalization of unary ^
to mean domain.
And in an axiomatic sort of way, it corresponds to those theories
of math that build up the integers by counting set elements. The
"argument" that produces 5 is 0..4. And it works out that +^5 == 5.
But the generalization to hashes is even cooler because I can say
my %thishash{^%thathash};
or some such to duplicate the "shape" regardless of the typology
of %thathash.
Larry
