in reply to Re: Re: Parsing strings into @ARGV
in thread Parsing strings into @ARGV

Yes, it's a bug. This is the offending part: 
sub shellwords {
    local(@lines) = @_;
    $lines[$#lines] =~ s/\s+$//;
    return(quotewords('\s+', 0, @lines));
}

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The bug is the unrestricted deletion of trailing whitespace - it shouldn't delete whitespace that's preceeded by the right number of backslashes. I'll see if I can come up with a patch later tonight.

Note that that's not the only case where Text::ParseWords and my shell (bash) disagrees. Given the string "foo\'bar", my shell parses that as foo\'bar, while Text::ParseWords turns it into foo'bar.

Abigail

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Re: Re: Parsing strings into @ARGV
by mirod (Canon) on Apr 23, 2004 at 16:15 UTC

    Yes, I saw that, here is my fix:

        $lines[$#lines] =~ s{(\\.)?\s*$}{defined $1 ? $1 : ''}e;

    I don't really like it but it passes my tests.:

    #!/usr/bin/perl -w
use strict; 

use Test::More qw(no_plan);

while( <DATA>)
  { my( $input, $expected)= m{^'(.*?)'\s*=>\s*'(.*?)'};
    (my $trimmed= $input)=~ s{(\\.)?\s*$}{defined $1 ? $1 : ''}e;
    is( $trimmed, $expected, "'$input'");
  }

__DATA__
't'    =>'t' 
't  '  =>'t'
't\ '  =>'t\ '
't\  ' =>'t\ '
't\ \ '=>'t\ \ '

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      Your solution fails on 't\\\ ', yielding 't\\\', but I expect 't\\\ '. 

          $ echo t\\\  | cat -e
    t\ $

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      Abigail

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[d/l]

        Let's try again, trying to keep the regexp anchored at the end:

        s{(\\*)(\s+)$}{ if( $1)
                  { if( length( $1) % 2) { $1 . substr( $2, 0, 1) }
                    else                 { $1 }
                  }
                else
                  { '' }
              }e;

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        A bit ugly, but I would think it works: keep the first whitespace in the final sequence if it comes after an odd number of \

        s{^((\\.|.)*?)\s*$}{defined $1 ? $1 : ''}e; works too, but I would suspect it is slower (no, I don't have a benchmark to prove it).

        The test again:

        #!/usr/bin/perl -w
use strict; 

use Test::More qw(no_plan);

while( <DATA>)
  { my( $input, $expected)= m{^'(.*?)'\s*=>\s*'(.*?)'};
    #(my $trimmed= $input)=~ s{^((\\.|.)*?)\s*$}{defined $1 ? $1 : ''}
+e;
    (my $trimmed= $input)=~ s{(\\*)(\s+)$}{ if( $1)
                                              { if( length( $1) % 2) {
+ $1 . substr( $2, 0, 1) }
                                                else               { $
+1 }
                                              }
                                            else
                                              { '' }
                              }e;
    is( $trimmed, $expected, "'$input'");
  }

__DATA__
''      => ''
't'     => 't' 
't  '   => 't'
't\ '   => 't\ '
't\  '  => 't\ '
't\ \ ' => 't\ \ '
't\\\ ' => 't\\\ '
't\\ ' => 't\\'

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Re: Re: Parsing strings into @ARGV
by mirod (Canon) on Apr 23, 2004 at 16:24 UTC

    bash, sh, csh and tcsh all give foo\'bar. This one looks more of a pain to fix.

    Are there tests for Text::ParseWords somewhere? The CPAN version has nothing, which makes it quite dangerous to work on it.

[reply]

      There are some really old tests in bleadperl. I think they might date back to 5.6.0 or 5.6.1.

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