Re^3: sub that sets $_

[anonymized user 468275]

No - each iteration returns a chunk into $_ in the for or foreach loop.

[holli]

definitly not.

use FTest;

my $test = new FTest ();

print foreach $test->foo;
print for     $test->foo;

Meanwhile in a module

package FTest;

sub new { return bless {}, shift; }
sub foo { return 1; }

1;

That code prints "11". I you were correct that would be an endless loop.

[anonymized user 468275]

I have to pass there because I don't understand what this has to do with $_ being a default for/foreach parameter.

[holli]

I have to pass there because I don't understand what this has to do with $_ being a default for/foreach parameter.

Well, nothing. $_ is the default variable for a for/foreach loop. That's not the point.

The point here is that the return value of a subroutine or method does not set $_ automatically. You suggested to use a for/foreach loop instead of a while loop, and that will not work because the method "chunk" is a iterator that only returns a single scalar per call. Thus, since for/foreach works on lists, the loops block will only be executed once.

In the while-loop however the block will be executed for every iteration until "chunk" returns false.

To make for/foreach work here, the ChunkReader-class would have to return a list of chunks and that, as said, is a waste of memory.