Beefy Boxes and Bandwidth Generously Provided by pair Networks
The stupid question is the question not asked
 
PerlMonks  

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??
Though you might be able to parse this with a fancy regex, a simple state machine would in my opinion be easier to read and less complicated to write and debug. If I understand your post correctly, your string has four tokens:
  • quoted strings - opaque between the quotes
  • runs of non-whitespace/non-close parenthesis that begin with anything but an open parenthesis or double quote, /[^)("][^)\s]*/.
  • runs of whitespace used as a separator between the first two types of tokens
  • parenthesized strings that may contain any of the first three types of tokens.

Assuming there are no parenthesized tokens within parenthesized tokens, you could use something like this:

use strict; use warnings; while (my $line = <DATA>) { chomp $line; # store tokens other than separators my @aTokens; # state: are we inside or outside of a parenthesized token? my $bParen; my $sInParens=''; while ($line =~ /("[^"]+"|\(|\)|[^)\s]+|\s+)/g) { my $sToken = $1; if ($sToken eq '(') { #starting a parenthesized token $bParen=1; } elsif ($sToken eq ')') { #ending a parenthesized token: add it to the list $bParen=0; push @aTokens, "($sInParens)"; $sInParens=''; } elsif ($bParen) { # in the middle of a parenthesized token $sInParens .= $sToken; } elsif ($sToken =~ /^\S/) { # not a parenthesized token # either a quoted or unquoted non-whitespace token # add it to the list push @aTokens, $sToken; } } local $"='> <'; printf "input : %s\n%s", "<$line>", "tokens: <@aTokens>"; } __DATA__ xxx "()" ("charset" "ISO-8859-1") (")") "xxx"

If you also need parenthesized tokens within parenthesized tokens, they the loop is only slightly more complicated. You would need to change the flag $bParen to a counter that was incremented for each '(' and decremented for each ')' found. You would then build the token until $iParenCount returned to 0. Parentheses within quotes will have no effect on this count because the "[^"] run insures that only parentheses outside of quotes will get parsed into separate tokens:

use strict; use warnings; while (my $line = <DATA>) { chomp $line; my @aTokens; my $sInParens=''; my $iParenCount; while ($line =~ /("[^"]+"|\(|\)|[^)\s]*|\s+)/g) { my $sToken = $1; if ($sToken eq '(') { if ($iParenCount) { $sInParens .= $sToken; } $iParenCount++; } elsif ($sToken eq ')') { $iParenCount--; if ($iParenCount) { $sInParens .= $sToken; } else { push @aTokens, "($sInParens)"; $sInParens=''; } } elsif ($iParenCount) { $sInParens .= $sToken; } elsif ($sToken =~ /^\S/) { push @aTokens, $sToken; } } local $"='> <'; print "paren count: $iParenCount\n"; printf "input : %s\n%s", "<$line>", "tokens: <@aTokens>\n"; } __DATA__ xxx "()" ("charset" "ISO-8859-1") (")") "xxx" ((a)(b)(c)) yyy

Best, beth

Update: added some discussion about handling nested parenthesized tokens.

Update: Fixed overly greedy regex


In reply to Re: Extracting a parenthesized fragment from a string by ELISHEVA
in thread Extracting a parenthesized fragment from a string by fce2

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":



  • Are you posting in the right place? Check out Where do I post X? to know for sure.
  • Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
    <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
  • Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
  • Want more info? How to link or or How to display code and escape characters are good places to start.
Log In?
Username:
Password:

What's my password?
Create A New User
Domain Nodelet?
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others cooling their heels in the Monastery: (4)
As of 2022-08-17 10:36 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    No recent polls found

    Notices?