Special character in the file exit the while loop in Perl

问题

I wrote a simple parser for a .txt file with the following instructions:

my $file2 = "test.txt";
open ($process, "<",$file2) or die "couldn't manage to open the file:$file2!";

while (<$process>)

{

...

}

In some files that I am trying to parse there is a special character that is like the right arrow (->) and that I don't manage to paste here from the file. Every time the parser hits that character (->), it exits the file without processing it till the end.

Is there a way to avoid it and continue processing the file till the very end?

I am using perl 5.6.1 (I cannot use a newer one) and the files that I need to process might have these special characters.

Thanks for your help.

回答1:

I don't think it's perl that's causing your problem, but almost certainly something in that middle missing block. Are you using eval in the while block on the input from the file? This is a minimal example that shows that the stream containing -> doesn't cause difficulties:

#!/usr/bin/env perl
use warnings;
use strict;

while(<DATA>) {
  print "Data[$.]: $_";
}

__DATA__
this is some data
this is also some data
-> this looks fine
foo->dingle also looks fine

This produces:

$ perl ./foo.pl 
Data[1]: this is some data
Data[2]: this is also some data
Data[3]: -> this looks fine
Data[4]: foo->dingle also looks fine

So, the -> characters in perl are special:

"-> " is an infix dereference operator, just as it is in C and C++. If the right side is either a [...] , {...} , or a (...) subscript, then the left side must be either a hard or symbolic reference to an array, a hash, or a subroutine respectively. (Or technically speaking, a location capable of holding a hard reference, if it's an array or hash reference being used for assignment.) See perlreftut and perlref.

Otherwise, the right side is a method name or a simple scalar variable containing either the method name or a subroutine reference, and the left side must be either an object (a blessed reference) or a class name (that is, a package name). See perlobj.

So if I had to guess, you're definitely using eval to try to parse your content and it's failing to dereference the left side of the operator and crashing. Please provide command line error messages or the code in the while loop if you want further assistance.

来源：https://stackoverflow.com/questions/21950579/special-character-in-the-file-exit-the-while-loop-in-perl