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Re^2: Help with a regular expression for file name parsing

by bontchev (Sexton)
on Dec 07, 2011 at 12:01 UTC ( #942232=note: print w/ replies, xml ) Need Help??


in reply to Re: Help with a regular expression for file name parsing
in thread Help with a regular expression for file name parsing

I am sorry, but I can't make sense of your answer. :-( If the part marked as "code" is supposed to be a script that works - well, it doesn't; it just produces a bunch of errors.

But let's concentrate just on the regular expression, because this is what I asked for. Sadly, that doesn't work, either. :-(

Let's start with something easy:

my $data = "\@include test"; if ($data =~ /\@include\s+('[^']+'|"[^"]+"|.+?(?<!\\))\s+/g) { print "File name: \"$1\"\n"; }

This doesn't output anything at all, meaning that the parsing fails.

If we set

my $data = "\@include \'test test\'";

this outputs

File name: "'test"

which is totally wrong. It should output

File name: "test test"

If we try

my $data = "\@include \"test test\"";

this produces the similarly wrong

File name: ""test"

And finally, if we try

my $data = "\@include test\\ test";

it also produces no output, meaning that the matching fails

Any better suggestions?


Comment on Re^2: Help with a regular expression for file name parsing
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Re^3: Help with a regular expression for file name parsing
by Anonymous Monk on Dec 07, 2011 at 12:21 UTC

    Any better suggestions?

    Learn to copy paste better :) because the regex you're using, isn't the same one BrowserUk posted

    His regex works, despite him posting the code in the context of his REPL (Read Eval Print Loop), see RFC: IPerl - Interactive Perl ( read-eval-print loop ), Re^6: RFC: IPerl - Interactive Perl ( read-eval-print loop ) (x)

    I checked

    #!/usr/bin/perl -- #~ 2011-12-07-04:10:56PDT by Anonymous Monk #~ perltidy -csc -otr -opr -ce -nibc -i=4 use strict; use warnings; use autodie; # dies if open/close... fail Main( @ARGV ); exit( 0 ); sub Main { if ( @_ == 2 ) { NotDemoMeaningfulName(@_); } else { Demo(); print '#' x 33 ,"\n", Usage(); } } ## end sub Main sub NotDemoMeaningfulName { my ( $inputFile, $outputFile ) = @_; open my ($inFh), '<', $inputFile; open my ($outFh), '>', $outputFile; while( defined( my $data = <$inFh>) ){ print $outFh "$_\n" for $data =~ m[\@include\s('[^']+'|"[^"]+"|.+?(?<!\\))\s]g +; # /\@include\s+('[^']+'|"[^"]+"|.+?(?<!\\))\s+ +/g } close $inFh; close $outFh; } ## end sub NotDemoMeaningfulName sub Usage { <<"__USAGE__"; $0 $0 dataFile newDataFile __USAGE__ } ## end sub Usage sub Demo { my ( $Input, $WantedOutput ) = DemoData(); NotDemoMeaningfulName( \$Input, \my $Output ); require Test::More; Test::More::is( $Output, $WantedOutput, ' NotDemoMeaningfulName Works Aas Designed' ); Test::More::done_testing(); print "\n$Output\n"; } ## end sub Demo sub DemoData { #~ http://perlmonks... my $One = <<'__One__'; @include test #some "random stuff" @include "some file" did you parse that? #more 'random' stuff @include 'another file' you sure? #and more random stuff @include yet\ another\ file positive? __One__ #~ http://perlmonks... my $Two = <<'__Two__'; test "some file" 'another file' yet\ another\ file __Two__ return $One, $Two; } ## end sub DemoData __END__ $ perl pm.re.942167.pl ok 1 - NotDemoMeaningfulName Works Aas Designed 1..1 test "some file" 'another file' yet\ another\ file ################################# pm.re.942167.pl pm.re.942167.pl dataFile newDataFile

      You checked what? I asked for a regular expression - not for three pages of code and a link to somebody's totally irrelevant custom module!

      Meanwhile, I figured out that the horrible BBoard software which this site uses simply mangles the posted code and to get the real stuff, you have to click on the "download" linke (which doesn't download!) and cut-and-paste from the page that opens.

      So, I managed to make TJPride's script output something meaningful:

      "some file" 'another file' yet\ another\ file

      Unfortunately, it is also wrong. This is not the proper output. The proper output, which such data, would be:

      some file another file yet another file

      Furthermore, I don't want all the stuff loaded into some kind of an array and everything in that array matched simultaneously. I have to do other stuff with each line, you know? I want to process the file line-by-line and, for this particular problem, I need a regular expression that fetches the file name after the "@include" keyword.

      Let's make this very simple, shall we? Consider this snippet of code:

      my $data = SOME STRING; if ($data =~ SOME EXPRESSION) { print "File name: \"$_\"\n"; }

      Question: What should SOME EXPRESSION be, so that if SOME STRING is

      "\@include file"

      or

      "\@include \"some file\""

      or

      "\@include another\\ file"

      the output is respectively

      File name: "file"

      or

      File name: "some file"

      or

      File name: "another file"

      Please do not answer, unless you have tested that your answer actually produces the desired output.

        Question: What should SOME EXPRESSION be, so that if SOME STRING is...

        Such a regular expression cannot exist, not in an if block

        You can match the filename portion (for which you already got a regex that works), but you have to remove the quotes and escapes afterwards (using s///|substitution operator)

        In short, you want a function that does the job

Re^3: Help with a regular expression for file name parsing
by BrowserUk (Pope) on Dec 07, 2011 at 19:08 UTC
    Any better suggestions?

    For you, no. At least none that would be considered polite.


    With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.

    The start of some sanity?

      For you, no. At least none that would be considered polite.

      Too bad. Then either you or I have come to the wrong place.

        Then either you or I have come to the wrong place.

        Hm. I've been hanging around here for the best part of a decade. What does that tell you?


        With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
        Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
        "Science is about questioning the status quo. Questioning authority".
        In the absence of evidence, opinion is indistinguishable from prejudice.

        The start of some sanity?

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