note
Anonymous Monk
<p>The example in random tip #16 does not explicitly spell out that you need to :</p>
<code>use Text::DelimMatch;</code>
<p>and in the grammar definition you need a rule :</p>
<code>newline: "\n"</code>
<p>With those two things in place the code works fine for parsing multi line HTML comments.</p>
<p>Parsing multi line C style comments is complicated by the fact that * is a regexp character so it needs escaping. I managed to get the following code to work OK based on technique outlined in the tip. I'm sure it could be done better but I was struggling with the escaping</p>
<code>
# Function to cope with multiline comments
# Must be placed in main section of program
sub parse_multilinecomment
{
my $text = shift;
my $mc = new Text::DelimMatch( '\\/\\*', '\\*\\/' );
my ( $p, $m, $r ) = $mc->match( '/*' . $text );
if ($p) {
$text = $p;
}
else {
$text = "";
}
$text .= $r if ($r);
$m =~ s/^\/\*//;
$m =~ s/\*\/$//;
return $text, $m;
}
</code>
<p>and the grammar rules :</p>
<code>
newline: "\n"
multilinecomment:
<skip: qr/[ \t]*/> newline(0..) '/*'
{
($text,$return) = main::parse_multilinecomment($text);
print $return . "\n";
$return = ['xcomment',$return];
}
</code>
<p>Successfully matches the following example :</p>
<code>
/*
A multiple line
/*
with nested
*/
comment
*/
</code>
<p>Hope this may help someone</p>
<p>Adrian</p>
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