Re^2: Using perlclass 'methods'

[kikuchiyo]

This is not the correct explanation. Deparse helps:

unexpected OP_METHSTART at /usr/share/perl5/B/Deparse.pm line 1674.
unexpected OP_METHSTART at /usr/share/perl5/B/Deparse.pm line 1674.
sub BEGIN {
    require v5.38.0;
    ()
}
use warnings;
use strict;
no feature ':all';
use feature ':5.38';
use experimental ('class');
BEGIN {${^WARNING_BITS} = "\x55\x55\x55\x55\x55\x55\x55\x55\x55\x55\x5
+5\x55\x55\x55\x55\x55\x55\x55\x55\x51\x55"}
use feature 'class';
{
    package Gear;
    ;
    sub ratio : method {
        XXX;
        return $chainring / $cog;
    }
    sub gear_inches : method {
        XXX;
        return ratio(*$rim + $tire * 2);
    }
}
say 'Gear'->new('chainring', 52, 'cog', 11, 'rim', 26, 'tire', 1.5)->g
+ear_inches;

(I had to modify the code a bit because I don't have 5.40)

So it takes everything that comes after the method name as the argument, so the * is interpreted as a glob dereference.

Note that B::Deparse also struggles with the new class feature.

[haj]

Thanks for the fix!

This is also a showcase some quirks of the Perl language:

• Parentheses are optional after method and subroutine calls. A method needs at least one parameter, and it was not provided with the $self-> syntax, so Perl picks up whatever comes next.
• The * is a valid (but fortunately rarely used these days) sigil. It is not a multiplication here, but indicates a glob reference.
• Really quirky: Spaces are allowed between a sigil and its identifier. So the identifier of * $rim is $rim, which is a symbolic reference.

use v5.40.0 implies "strict refs", so Perl complains about *$rim even before trying to use it as the invocant of the method (as I originally thought).