yayitssegfault!

gistfile1.txt

┌─[tadzik@yavin4]─[~/src/perl/IO-Select] 
└─[%]─> PERL6LIB=lib parrot -g ms2  ~/src/nom/perl6.pbc test.pl 
(IO<26532416>,).list
(IO<26532416>,).list
┌─[tadzik@yavin4]─[~/src/perl/IO-Select] 
└─[%]─> PERL6LIB=lib parrot -g gms ~/src/nom/perl6.pbc test.pl   
(IO<14171808>,).list
zsh: segmentation fault  PERL6LIB=lib parrot -g gms ~/src/nom/perl6.pbc test.pl

lib,IO,Select.pm

pir::loadlib__Ps('select');

class IO::Select {
    has $!pmc;
    has $!iter = 'a';
    has %!handles;
    
    submethod BUILD {
        $!pmc := pir::new__Ps('Select');
    }

    method add(IO $handle) {
        %!handles{$!iter} = $handle;
        my $fh := nqp::getattr(
            pir::perl6_decontainerize__PP($handle), IO, '$!PIO'
        );
        my $mode = 4;
        $mode += 2 if nqp::p6box_s($fh.mode) ~~ /w/;
        $mode += 1 if nqp::p6box_s($fh.mode) ~~ /r/;
        # XXX No idea how to obtain an actual fd or any other unique
        # identifier, so I'll just assign consequent letters of alphabet
        # to each one
        $!pmc.update($fh, nqp::unbox_s($!iter), nqp::unbox_i($mode));
        $!iter.=succ;
    }

    method remove(IO $handle) {
        $!pmc.remove(nqp::getattr($handle, IO, '$!PIO'));
    }

    method can_read($timeout as Num) {
        my Mu $ids := nqp::getattr(
            $!pmc.can_write(nqp::unbox_n($timeout)), Parcel, '$!storage'
        );
        my Int $elems := nqp::p6box_i(pir::elements($ids));
        my @res;
        loop (my Int $i = 0; $i < $elems; $i++) {
            my Str $item := nqp::p6box_s(nqp::atpos($ids, nqp::unbox_i($i)));
            @res.push: $item;
        }
        return @res.map: { %!handles{$_} };
    }

    method can_write($timeout as Num) {
        my Mu $ids := nqp::getattr(
            $!pmc.can_write(nqp::unbox_n($timeout)), Parcel, '$!storage'
        );
        my Int $elems := nqp::p6box_i(pir::elements($ids));
        my @res;
        loop (my Int $i = 0; $i < $elems; $i++) {
            my Str $item := nqp::p6box_s(nqp::atpos($ids, nqp::unbox_i($i)));
            @res.push: $item;
        }
        return @res.map: { %!handles{$_} };
    }
}

test.pl

use IO::Select;

my $r = open 'README';
my $w = open 'WRITEME', :w;

my $select = IO::Select.new;

$select.add($r);
$select.add($w);

say $select.can_read(0).perl;
say $select.can_write(0).perl;