Re: is rw basically a null-op on objects/references?

Juerd skribis 2005-04-28 14:47 (+0200):
> Yes, because a pair is an object (reference), and it's not the .value
> that you're passing ro.

An example of what would go wrong:

    for %hash.pairs>>.value -> $value {
        $value = ...;
    }

But this will work:

    for %hash.pairs>>.value {
        $_ = ...;
    }

And this again won't:

    for %hash.pairs>>.value -> $_ {
        $_ = ...;
    }

This makes "upgrading" a block to use an explicit name a painful
experience if you happen to mutate its value, because you have to
specify 'is rw', which I'm sure will bite many people many times.

This is why I want <->, so that the default for

    for ... { ... }

can be

    for ... <-> $_ { ... }

rather than the unexpected

    for ... -> $_ is rw { ... }

so that $_ is the default, and no special default-magic for "is rw" is
needed. Of course, "<-> $_" and "-> $_" are 100% equal internally.


Juerd
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• is rw basically a null-op on objects/references? by Ingo Blechschmidt
• Re: is rw basically a null-op on objects/references? by Juerd
• Re: is rw basically a null-op on objects/references? by Thomas Sandlaß
• Re: is rw basically a null-op on objects/references? by Juerd
• Re: is rw basically a null-op on objects/references? by Juerd