Ok, I stand corrected, but I never use the two condition conditional. I believe the
example presented here would not work, since there is no assignment to $line before
the test for "__END__". It could be assigned later, after the test, but that's
generally bad practice. Second, the while() will not exit when $exitloop is true
since an OR was used.
while(<FH> && !$exitloop )
would work.
while(<FH> || $exitloop){
if($line eq "__END__"){
$exitloop = true;
}
# Do other stuff here...
}
-----Original Message-----
From: Ronald J Kimball [mailto:[EMAIL PROTECTED]
Sent: Monday, June 16, 2003 11:27 AM
To: Daschbach, John L
Cc: Thomas De Groote; Nicholas G. Thornton; [EMAIL PROTECTED]
Subject: Re: [MacPerl] exiting a while() loop
On Mon, Jun 16, 2003 at 11:19:21AM -0700, Daschbach, John L wrote:
>
> > > Add an extra variable and set that, like
> > >
> > > $exitloop = false;
> > > while(<FH> || $exitloop){
> >
> > What do you suppose happens to the input from <FH> in that line of code?
>
> It's in $_ as it always is.
Ah ha! No, it is not. It is discarded.
In the loop:
while(<FH> || $exitloop) {
}
the input read from <FH> is not assigned to $_, because the implicit
assignment only happens when the input operator is the only thing in the
conditional.
perldoc perlop:
Ordinarily you must assign the returned value to a vari-
able, but there is one situation where an automatic
assignment happens. If and only if the input symbol is
the only thing inside the conditional of a "while" state-
ment (even if disguised as a "for(;;)" loop), the value is
automatically assigned to the global variable $_, destroy-
ing whatever was there previously.
Ronald
