Re: PGE::Text::bracketed added to PGE

[Allison Randal]

On Oct 17, 2005, at 14:15, Patrick R. Michaud wrote:

I've just added a <PGE::Text::bracketed> subrule to PGE,
which is roughly analogous to the "bracketed" function in
Perl 5's Text::Balanced.
Like most PGE subrules, PGE::Text::bracketed can be called
as a subrule in a rule expression or directly via a subroutine call.
Thus, to extract quote-delimited text from a string:

    .local pmc bracketed
    bracketed = find_global "PGE::Text", "bracketed"

    $P0 = bracketed("'this quoted string' and other stuff", "'")

returns a match object into $P0 that contains C< 'this quoted  
string' >.
Delimiters can be escaped, thus

Shouldn't it contain C<this quoted string>? That is, shouldn't it  
remove the bracketing characters? Or at least hold the string without  
the brackets somewhere within the PGE::Text object? I'm getting:

  <PunieGrammar::term> => PMC 'PunieGrammar' => "(ok 1)" @ 6 {
      <PGE::Text::bracketed> => PMC 'PGE::Text' => "(ok 1)" @ 6
  }

But want something more like:

  <PunieGrammar::term> => PMC 'PunieGrammar' => "(ok 1)" @ 6 {
        <PGE::Text::bracketed> => PMC 'PGE::Text' => "(ok 1)" @ 6 {
                [0] => PMC 'PunieGrammar' => "ok 1" @ 7
        }
  }

So I can extract the parsed string. (If you squint and read "()" as  
double quotes, it makes more sense.)

At the moment there's not a mechanism to specify an alternate set
of delimiters from within a subrule, but this should be available in
the near future as a subrule parameter:

     <PGE::Text::balanced: {}()[]>     # delimited by {}, (), []
     <PGE::Text::balanced("<'\"")>     # delimited by <>, ", '

I have a use for this as soon as its done (or is it already done?)


And thanks very much for adding this feature. It's a big help!

Allison