Re: Regular expression to list all files of type in folder

[bart]

in reply to Regular expression to list all files of type in folder

Is there perhaps a file called "0" in the directory? That would make the loop prematurely break off.

[LanX]

> Is there perhaps a file called "0" in the directory? That would make the loop prematurely break off.

Thankfully this doesn't happen!!!

(I was ready to complain about rotten implementations...=)

Probably saved by one of these special magic behaviors of while

UPDATE:here it is

from perlop#I/O-Operators

The following lines are equivalent:

           while (defined($_ = <STDIN>)) { print; }
           while ($_ = <STDIN>) { print; }
           while (<STDIN>) { print; }
           for (;<STDIN>;) { print; }
           print while defined($_ = <STDIN>);
           print while ($_ = <STDIN>);
           print while <STDIN>;

This also behaves similarly, but avoids $_ :

           while (my $line = <STDIN>) { print $line }

In these loop constructs, the assigned value (whether assignment is automatic or explicit) is then tested to see whether it is defined. The defined test avoids problems where line has a string value that would be treated as false by Perl, for example a "" or a "0" with no trailing newline. If you really mean for such values to terminate the loop, they should be tested for explicitly:

doesn't mention readdir but I think it's a similar case (and a documentation hole)

[Anonymous Monk]

B::Deparse thinks so :)

$ perl -MO=Deparse,-p -le " opendir BLAH,'.'; while(readdir BLAH){prin
+t;}"
BEGIN { $/ = "\n"; $\ = "\n"; }
opendir(BLAH, '.');
while (defined(($_ = readdir(BLAH)))) {
    print($_);
}
-e syntax OK

[karlgoethebier]

Mmh, i tried to reproduce it exactly as described by Phinix and i get the files. Even when i add other files i get them. What do i miss?

Best regards, Karl

[bart]

What do i miss?

Perl version?

I'm sure the DWIM magic as demonstrated in this thread was added in some version of Perl, so an older perl can still exhibit the problem.