Peter Rabbitson wrote:
> I stumbled upon a script with the following assignment:
> ... = v(numeric value);
>
> I tried to see how it works and the following:
> my $a = v65;
> print $a;
>
> produces ascii 65 (capital A)
>
> Where can I read more about these assignment modifiers?
perldoc perldata
[snip]
Version Strings
Note: Version Strings (v-strings) have been deprecated. They will not
be available after Perl 5.8. The marginal benefits of v-strings were
greatly outweighed by the potential for Surprise and Confusion.
A literal of the form "v1.20.300.4000" is parsed as a string composed
of characters with the specified ordinals. This form, known as
v-strings, provides an alternative, more readable way to construct
strings, rather than use the somewhat less readable interpolation form
"\x{1}\x{14}\x{12c}\x{fa0}". This is useful for representing Unicode
strings, and for comparing version "numbers" using the string
comparison operators, "cmp", "gt", "lt" etc. If there are two or more
dots in the literal, the leading "v" may be omitted.
print v9786; # prints UTF-8 encoded SMILEY, "\x{263a}"
print v102.111.111; # prints "foo"
print 102.111.111; # same
Such literals are accepted by both "require" and "use" for doing a
version check. The $^V special variable also contains the running Perl
interpreter's version in this form. See "$^V" in perlvar. Note that
using the v-strings for IPv4 addresses is not portable unless you also
use the inet_aton()/inet_ntoa() routines of the Socket package.
Note that since Perl 5.8.1 the single-number v-strings (like "v65") are
not v-strings before the "=>" operator (which is usually used to
separate a hash key from a hash value), instead they are interpreted as
literal strings ('v65'). They were v-strings from Perl 5.6.0 to Perl
5.8.0, but that caused more confusion and breakage than good.
Multi-number v-strings like "v65.66" and 65.66.67 continue to be
v-strings always.
John
--
use Perl;
program
fulfillment
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