Solo has asked for the wisdom of the Perl Monks concerning the following question:

I'm parsing multi-line records that looks like so: 

recordID: blah
   fieldname: value
   foo      : 
   bar      : baz
...

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With the regular expression like so: 

while ( /\G\s*([^:]+?)\s*:\s*(.+?)?\s*$/mg ) {...}

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My problem is that sometimes value is empty and I'm matching the whole next line, rather than not matching the optional (.+?)?. I haven't used /s, so I thought .+ wouldn't match a newline, but it seems to be. What am I missing?

TIA!

--Solo

--
You said you wanted to be around when I made a mistake; well, this could be it, sweetheart.

Replies are listed 'Best First'.
Re: Regex problem with .+ matching newlines without /s
by ccn (Vicar) on Aug 31, 2004 at 17:40 UTC

    Because \s matches newlines

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Re: Regex problem with .+ matching newlines without /s
by ysth (Canon) on Aug 31, 2004 at 18:15 UTC
    What ccn said. If the thing to the right and left of the : need to be on the same line, use [^\S\n] instead of \s. Also, I think (.+?)? is a little on the obfuscated side. I would make from the : onward :[^\S\n]*(.*?)\s*$ (though I think that leaves $2 blank instead of undef.) (The final \s can be left as is unless you want to prevent the regex from swallowing up blank lines.)
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      (.+?)? resulted from my (possibly obfuscated) thought process.

      [^\S\n] did the trick, thanks much. I rarely deal with multi-line matches and didn't know that about \s. Seems to me there ought to be an easier way to express non-newline whitespace than [^\S\n].

      --Solo

      --
      You said you wanted to be around when I made a mistake; well, this could be it, sweetheart.
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Re: Regex problem with .+ matching newlines without /s
by sleepingsquirrel (Chaplain) on Aug 31, 2004 at 19:45 UTC
    Just for fun... 
    $_ = <<END;
recordID: blah
   fieldname: value
   foo      : 
   bar      : baz
END

for (split /\n\s*/)
{
    ($left, $right) = split /\s*:\s*/;

    #do stuff...
    printf "%10s:\t\'%s\'\n", $left, $right;
}

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    -- All code is 100% tested and functional unless otherwise noted.
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[d/l]

      Don't forget to add a limit to split in case there are more colons than one in some line.

      Makeshifts last the longest.

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