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#! /usr/local/bin/perl -sw
# PARSE LOGICAL EXPRESSIONS
$RD::TRACE=1;
use Parse::RecDescent;
$grammar =
q{
expr : disj no_garbage
no_garbage: /^\s*$/
| <error: Trailing garbage>
disj : conj ('or' conj)(s?)
conj : unary ('and' unary)(s?)
unary : 'not' atom
| '(' disj ( ')' | <error> )
| atom
atom : /<.+?>/
};
$parse = new Parse::RecDescent ($grammar);
$input = '';
print "> ";
while (<>)
{
if (/^\.$/) { defined $parse->expr($input) or print "huh?\n"; $input = '' }
else { chomp; $input .= " $_" }
print "> ";
}
|
