Anyone care to pick holes in this little expression of some Perl 6 core
types as collections? I mean, other than missing methods ;)
role Collection[\$types] {
has Seq[$types] @.members;
}
role Set[::T = Item] does Collection[T] where {
all(.members) =:= one(.members);
};
role Pair[::K = Item, ::V = Item] does Seq[K,V] {
method key of K { .[0] }
method value of V { .[1] }
};
role Mapping[::K = Item, ::V = Item] does Collection[Pair[K,V]] {
all(.members).does(Pair) and
all(.members).key =:= one(.members).key;
}
role Hash[Str ::K, ::V = Item] does Mapping[K, V]
where { all(.members).key == one(.members).key }
{
method post_circumfix:<{ }> (K $key) of V|Undefined {
my $seq = first { .key == $key } &.members;
$seq ?? $seq.value :: undef;
}
}
role ArrayItem[::V = Item] does Seq[Int, V] {
method index of Int { .[0] }
method value of Item { .[1] }
};
role Array of Collection[ArrayItem]
where { all(.members).index == one(.members).index }
{
method post_circumfix:<[ ]> (Int $index) of Item {
my $seq = first { .index == $index } &.members;
$seq ?? $seq.value :: undef;
}
}
I'll take the feedback I get, and try to make a set of Perl 6 classes in
the pugs project that look and feel just like regular Perl 6 hash/arrays
but are expressed in more elementary particles.
Cheers,
Sam.
