=>'s container and binding semantics

[Ingo Blechschmidt]

Hi,

    my ($key, $value) = <key val>;
    my $pair          = ($key => $value);

    $pair.key = "new";
    # Should this fail ("cannot modify a constant")?
    # Should this update $pair.key, but leave $key untouched?
    # Should this update $pair.key, implicitly updating $key as well?

    $pair.value = "new";
    # Should this fail ("cannot modify a constant")?
    # Should this update $pair.value, but leave $value untouched?
    # Should this update $pair.value, implicitly updating $value
    # as well?

If setting $pair.value changes $value, should rebinding $pair.value
cause the binding to get destroyed:

    $pair.value := $some_other_var;
    $pair.value = "new";
    # $value unchanged, $some_other_var set to "new"

If setting $pair.value does not change $value, should binding
$pair.value to $value do what I mean:

    $pair.value := $value;
    $pair.value = "new";
    # $value changed


--Ingo