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Re^5: Parser Performance Question (updated)

by LanX (Saint)
on Oct 06, 2017 at 02:08 UTC ( [id://1200789]=note: print w/replies, xml ) Need Help??


in reply to Re^4: Parser Performance Question (updated)
in thread Parser Performance Question

> q< \\" > will be parsed as an escaped quote

I don't understand, it IS an escaped quote and it works for me:

DB<175> $re = qr/ " (?: \\\\ | \\" | [^"] )* " /x; DB<176> p $a= q<x "..\\".." x> x "..\".." x DB<177> $a =~ /$re/; print $& "..\".."

update

maybe you should show us how you'd escape a double-quote.

Cheers Rolf
(addicted to the Perl Programming Language and ☆☆☆☆ :)
Je suis Charlie!

Replies are listed 'Best First'.
Re^6: Parser Performance Question (updated)
by Eily (Monsignor) on Oct 06, 2017 at 08:02 UTC

    Meh, this will teach me about posting when I can't test. I meant q< \\\\" >; but thought the \ wouldn't escape the next one. The case where the \ just before the " is litteral because escaped, so it can't escape the ".

    use v5.20; use Data::Dump qw( pp ); my $str = <<STR; " .. \\\\" .. " STR print $str; my %re = (LanX => qr/ " (?: \\\\ | \\" | [^"] )* " /x, Eily => qr/ " (?: [^\\] | \\. )* " /x); $str =~ /$re{$_}/ and say "$_ found $&" for keys %re;
    " .. \\" .. " Eily found " .. \\" .. " LanX found " .. \\"

      >
      " .. \\" .. " Eily found " .. \\" .. " LanX found " .. \\"

      Well, you proved that my version is correct and yours doesn't work.

      :p

      Cheers Rolf
      (addicted to the Perl Programming Language and ☆☆☆☆ :)
      Je suis Charlie!

        Hu, how did I ever reach sainthood in our book? Eily => qr/ " (?: [^"\\] | \\. )* " /x); <= added the missing " in the character class

        use Data::Dump qw( pp ); my $str = <<STR; " .. \\" .. STR print $str; my %re = (LanX => qr/ " (?: \\\\ | \\" | [^"] )* " /x, Eily => qr/ " (?: [^"\\] | \\. )* " /x); $str =~ /$re{$_}/ and say "$_ found $&" or say "$_ found nothing" for +keys %re;
        " .. \" .. Eily found nothing LanX found " .. \"

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