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Postings from March 2012
On Wed, Mar 14, 2012 at 7:48 AM, John Douglas Porter
<johndporter@yahoo.com> wrote:
> So is that the Perl 6 smart match operator? or something else?
The latter.
> In any case... How does it work here? It looks like it's functionally
> equivalent to scalar()... but why?
Perl's ~ is operand sensitive; if its operand has a numeric value
(either because it was assigned a number, the result of a numeric
operation, or had been used in numeric context), it is a numeric
bitwise or (implicitly converting to UV, or under the scope of use
integer, IV, first); otherwise it is a string bitwise or.
For most inputs, in either case it can be repeated to reproduce the
original value and acts just like scalar().
Examples of exceptions:
# floating point
$x = 1.23; print ~~$x; # 1
# string used in numeric context
$x = "1.23"; print ~~$x if $x != 0; # 1
# integer out of range
use Config '%Config';
$x=2**(8*$Config{uvsize}); print ~~$x; # max uv
$x = -1; print ~~$x; # max uv
$x = 2**(8*$Config{uvsize}-1); use integer; print ~~$x; # min iv
$x = -2**(8*$Config{uvsize}-1)-1; use integer; print ~~$x; # min iv
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