trAvis - MANAGER

Edit File: demo_parsetree.pl

#!/usr/bin/perl -sw # PARSE LOGICAL EXPRESSIONS TO A "list of lists" PARSE TREE sub printtree { print " " x $_[0]; print "$_[1]:\n"; foreach ( @_[2..$#_] ) { if (ref($_)) { printtree($_[0]+1,@$_); } else { print " " x $_[0], "$_\n" } } print "\n"; } use Parse::RecDescent; $RD_AUTOACTION = q{ [@item] }; $grammar = q{ expr : disj disj : conj 'or' disj | conj conj : unary 'and' conj | unary unary : 'not' atom | '(' expr ')' | atom atom : /[a-z]+/i }; $parse = new Parse::RecDescent ($grammar); while (<DATA>) { my $tree = $parse->expr($_); printtree(0,@$tree) if $tree; } __DATA__ a and b and not c (c or d) and f