Re: print statement creates key in hash with reference to empty array??

Anno Siegel schreef:
> Dr.Ruud:
>> Abigail:
>>> Dr.Ruud:

>>>>    $ echo 'if( exists $hash{$key} ) { print "$hash($key)\n"; }' \
>>>>       | perl -MO=Deparse,-x7
>>>>
>>>>    exists $hash{$key} and do {
>>>>        print "$hash($key)\n"
>>>>    };
>>>>
>>>>  I don't know why the do-block is needed.
>>>
>>> Because the then part of an if statement is a block. 'do {}' turns a
>>> block into an expression.
>>
>> I still don't see why it isn't 'cleaned up' further in the special
>> case that the expression is one statement. As you can deduce, I
>> assume that the "do{}" is never necessary around a single statement,
>> that "()" is sufficient.
>
> No, the "do{}"s are necessary, there *must* be a statement in this
> place. It's just that the DWIM mechanism inserts them for you in many
> situations where little else would make sense.  What deparse shows is
> what perl actually compiles.

>From an earlier post:

  $ echo 'print "$hash{$key}\n" if exists $hash{$key};' \
       | perl -MO=Deparse,-x7

  exists $hash{$key} and print "$hash{$key}\n";

That doesn't get a do{}.


> Deparse can't very well suppress them either, once they're there.

And I just wondered why not, for cases like this one.

-- 
Affijn, Ruud

"Gewoon is een tijger."

.

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