I'm failing to use relative backreferences in \g-form in character classes.

Please note how [^\1] still works, but [^\g-1] fails.

Is there a better syntax within character classes?

I'm afraid I need to switch to negated look-aheads or hardcode different quotes.°

Debugger demo with perl-de0

The following regex tries to match quoted substrings in $1, the quote in $2

  DB<164> p $_
__'abc'__"def"__
  DB<165> x / ( (['"]) [^\2]*? \2 ) /gx     # OK
0  '\'abc\''
1  '\''
2  '"def"'
3  '"'
  DB<166> x / ( (['"]) [^\2]*? \g-1 ) /gx   # OK
0  '\'abc\''
1  '\''
2  '"def"'
3  '"'
  DB<167> x / ( (['"]) [^\g-1]*? \g-1 ) /gx # OOPS
Invalid [] range "\g-1" in regex; marked by <-- HERE in m/ ( (['"]) [^
+\g-1 <-- HERE ]*? \g-1 ) / at (eval 179)[c:/St\
rawberry/perl/lib/perl5db.pl:738] line 2.
 at (eval 179)[c:/Strawberry/perl/lib/perl5db.pl:738] line 2.
        eval 'no strict; ($@, $!, $^E, $,, $/, $\\, $^W) = @DB::saved;
+package main; $^D = $^D | $DB::db_stop;
  / ( ([\'"]) [^\\g-1]*? \\g-1 ) /gx;
' called at c:/Strawberry/perl/lib/perl5db.pl line 738
        DB::eval called at c:/Strawberry/perl/lib/perl5db.pl line 3138
        DB::DB called at -e line 1
  DB<168> p $]
5.032001
  DB<169>
[download]

FWIW: \g{-1} instead of \g-1 doesn't help either

This question is a follow-up to solution wanted for break-on-spaces (w/specifics)

update

°) or using (??{..})

SOLUTION

escaping the dash inside character classes helps, otherwise it's seen as a range

  DB<170> x / ( (['"]) [^\g\-1]*? \g-1 ) /gx
0  '\'abc\''
1  '\''
2  '"def"'
3  '"'
  DB<171> x / ( (['"]) [^\g{\-1}]*? \g-1 ) /gx
0  '\'abc\''
1  '\''
2  '"def"'
3  '"'
  DB<172> x / ( (['"]) [^\g2]*? \g-1 ) /gx
0  '\'abc\''
1  '\''
2  '"def"'
3  '"'
  DB<173>
[download]

The perl guide document "perlpacktut" contain the following command statements, which look like assignments.

    $UTF8{Euro} = pack( 'U', 0x20AC );
    # Equivalent to: $UTF8{Euro} = "\x{20ac}";

    $Unicode{Euro} = unpack( 'U', $UTF8{Euro} );
[download]

The tokens `$UTF8{Euro}` and `$Unicode{Euro}` seem to be treated as variables. However, the typical perl variables I am familiar with are of the form $v or ${v} but not $v{u}. In fact, the following code ends up with an error.

    #!/usr/bin/perl

    my $v{u} = "hello";
    print($v{u}, "\n");
[download]

syntax error at ./test.pl line 3, near "$v{u"

What are `$UTF8{Euro}` and `$Unicode{Euro}`? Which perl guide document explain this kind of token?

Thank you in advance.

I would like to convert between Unicode code points and UTF-8 character codes.

For example, the Unicode code point for the GREEK SMALL LETTER PI is U+03C0, and its UTF-8 character code is 0xCF80. So, if the string "U+03C0" (or "0x03C0") is entered, then I want the string "0xCF80" to be printed (without quotes). If the string "0xCF80" is entered, then I want the string "U+03C0" (or "0x03C0") to be printed (without quotes). Note that the desired output is NOT a character itself but a string showing the character code.

By the way, if your terminal is configured to display Unicode wide characters, then the following commands will show you the GREEK SMALL LETTER PI.

    perl -l12e 'print(chr(0x03c0))' -C
    perl -l12e 'print(pack("U0W*", 0xCF, 0x80))' -C
[download]

Thank you in advance.

 
DB<1> @ln=<STDIN>; <"FILE" 
DB<2> print "$ln[0] $ln[1]"
[download]

I think (hope) that's it. I've evolved an example I found on this board, but don't remember the original URL. It had some failing, where it didn't satisfy the above additional rules. That example is:

qr{((?>\\[^\\])|"(?:\\\\"|[^\\"]*)"|(?:'[^\\']*'|\S+))+}
[download]

My test inputs included "embedded case/line# answer,text" and which assumes testprog can remove '#comments' are:

# ln#, ans, test text
 1 3,This is simple.
 2 3,This is "so very simple".
 3 4,This "is so" very simple.
 4 2,This 'isn\'t nice.'
 5 2,This "isn\"t nice."
 6 3,This 'isn\\'t nice.'
 7 3,This "isn\\"t nice."
 8 2,This "isnt wrong."
 9 2,This 'isnt wrong.'
10 3,This 'isn\\'t wrong.
11 3,This "isn\\"t wrong.
12 3,This isn\'t horrible.
13 3,This isn\"t terrible.
14 3,This \"isnt unnice.\"
15 3,This \'isnt unnice.\'
16 2,This 'is not unnice.'
17 2,This "is not unnice."
18 3,a "bb cc" d
[download]

So far, my sample test-runs show lines/cases 4+5 to be in error.

That is the main problem, the rest is specific to my testing program, which I don't care about, but can be used to run the sample RE against the test cases (which are included in the source of the testing program). The test prog's output follows (Note -- like the testprog, don't care about the format, it was just to show me pass/fails"):

ResByLn:{ln=>1, wanted=>3, got=>[3]},[" p  "]
ResByLn:{ln=>2, wanted=>3, got=>[3]},[" p  "]
ResByLn:{ln=>3, wanted=>4, got=>[4]},[" p  "]
ResByLn:{ln=>4, wanted=>2, got=>[3]},["FAIL:<This "isn\"t nice.">"]
ResByLn:{ln=>5, wanted=>2, got=>[3]},["FAIL:<This 'isn\\'t nice.'>"]
ResByLn:{ln=>6, wanted=>3, got=>[3]},[" p  "]
ResByLn:{ln=>7, wanted=>3, got=>[3]},[" p  "]
ResByLn:{ln=>8, wanted=>2, got=>[2]},[" p  "]
ResByLn:{ln=>9, wanted=>2, got=>[2]},[" p  "]
ResByLn:{ln=>10, wanted=>3, got=>[3]},[" p  "]
ResByLn:{ln=>11, wanted=>3, got=>[3]},[" p  "]
ResByLn:{ln=>12, wanted=>3, got=>[3]},[" p  "]
ResByLn:{ln=>13, wanted=>3, got=>[3]},[" p  "]
ResByLn:{ln=>14, wanted=>3, got=>[3]},[" p  "]
ResByLn:{ln=>15, wanted=>3, got=>[3]},[" p  "]
ResByLn:{ln=>16, wanted=>2, got=>[2]},[" p  "]
ResByLn:{ln=>17, wanted=>2, got=>[2]},[" p  "]
ResByLn:{ln=>18, wanted=>3, got=>[3]},[" p  "]
[download]

For FAIL cases, I had it print the failing text, just to be sure I was failing on the line I thought I was.

The test prog takes an optional '-f' that filters output to only display the FAILing cases.

I repeat -- my main problem is finding an RE that I can use to break the test-cases into the correct number of capture-args (as broken by unquoted spaces). Am including my test prog, below for those that want to use it or see what I did. But the help I need is in fixing the 'RE' so all the test cases work. Thanks for any help!

#!/usr/bin/perl
use P;
# vim=:SetNumberAndWidth

if ( -t 0) { # unlikely to provide reliable test case
  open(STDIN, "<&=", "main::DATA") || die "opening internal tests: $!"
+;
}

my @lines = grep { defined $_ and ! /^\s*#/ } (<main::DATA>);

my @regex = ( qr{((?>\\[^\\])|"(?:\\\\"|[^\\"]*)"|(?:'[^\\']*'|\S+))+}
+ );

my $ln=0;
my $norm=0;
my @ResByLn;

sub lnout($$$) {
  my ($ans,$outp, $lnp) = @_;
  bless {wanted=>$ans, got=>$outp, ln=>$lnp}, q(ResByLn:);
}

sub txt($) {
  local $_=shift;
  my (undef, undef,$txt)=m{^\s*(\d+)\s+(\d+),(.*)};
  $txt;
}

my $only_fails = @ARGV && $ARGV[0] eq '-f' ? 1 : 0;

for (@lines) {
  ++$ln;
  my ($lnnum, $ans,$_)=m{^\s*(\d+)\s+(\d+),(.*)};
  my @got;
  for (my $r=0; $r<@regex; ++$r) {
    my $reg = $regex[$r];
    my @out =  grep {$_ } m{$reg}g;
    my $cnt = 0+@out;
    push @got,  $cnt;
  }
  $lnnum and push @outs, lnout($ans, \@got, $lnnum);
}


for my $o (@outs) {
  my $ans = $o->{wanted};
  my @out = @{$o->{got}};
  my $ln  = $o->{ln};
  my @rts;  #results
  for (my $i=0;$i<@out;++$i) {
    $rts[$i] = do {
      if ($ans==$out[$i]) { " p  " }
      else { "FAIL:" . do { 
          my $txt = txt($lines[$ln]);
          chomp $txt;
          "<$txt>"; 
        };
      }
    };
  }

  my @output_args=("%s,%s",$o,\@rts);

  # * Shows line-number, result-wanted, result-got + test-status
  # * if test-status is FAIL, shows corresponding test-txt between <> 
+(carats)
  #
  unless ($only_fails) {
    P @output_args;
  } else {
    my @fails = grep /FAIL/, P @output_args;
    foreach (@fails) {
      P "%s", $_;
    }
  }
}
# vim: ts=2 sw=2 ai number


__DATA__
# ln#, ans, test text
 1 3,This is simple.
 2 3,This is "so very simple".
 3 4,This "is so" very simple.
 4 2,This 'isn\'t nice.'
 5 2,This "isn\"t nice."
 6 3,This 'isn\\'t nice.'
 7 3,This "isn\\"t nice."
 8 2,This "isnt wrong."
 9 2,This 'isnt wrong.'
10 3,This 'isn\\'t wrong.
11 3,This "isn\\"t wrong.
12 3,This isn\'t horrible.
13 3,This isn\"t terrible.
14 3,This \"isnt unnice.\"
15 3,This \'isnt unnice.\'
16 2,This 'is not unnice.'
17 2,This "is not unnice."
18 3,a "bb cc" d
__END__
[download]

sub genHTMLTableRow
  {
    my $self = shift;
    my $args = shift;
    my $e = shift;
    my $ser = $e->{serial};
    my $pem = $ser.'.html';

. . .
[download]

CSP=HASH(0x800b1e060)
[download]

print map { "Key: $_ has Value:$self{$_}\n" } keys $self;
[download]

  Global symbol "%self" requires explicit package name (did you forget
+ to declare "my %self"?) at /root/bin/rcsp/blib/lib/CSP.pm line 861
[download]

Hi all, I want to write a script which should use extern programms for MRI-preprocessing, doing several processing commands to a bunch of data. For example: running brain extraction from the command line in linux I would write bet <inputimage> <nameforoutputimage> -m Then the programm bet in fsl would be opened and skull stripping would be performed, the output image would be saved in the same folder of the inputimage. In my script I want the outputimage to be saved in an other folder. Could anyone help me with this? I think there a lot of syntax errors ...

#!/usr/bin/perl

use strict;
use warnings;
use diagnostics;

my $dir = "usr/bin/Test_Protokoll"

my $001= "prob_001";
my $002= "prob_002";
my $003= "prob_003";

@filter: ("001", "002", "003");

#Brainextraction
foreach ("001", "002", "003")
{
   system ("bet SYNT_MPRAGE_T1_PD_B0corr YNT_MPRAGE_T1_PD_B0corr_brain
+ -m");
}
[download]