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Ingy döt Net 2013-04-10 23:57:08 -07:00
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commit b83f433714
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Task/Parsing-RPN-calculator-algorithm/Perl/parsing-rpn-calculator-algorithm.pl Normal file
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# RPN calculator
#
# Nigel Galloway April 2nd., 2012
#
$WSb = '(?:^|\s+)';
$WSa = '(?:\s+|$)';
$num = '([+-/]?(?:\.\d+|\d+(?:\.\d*)?))';
$op = '([-+*/^])';
sub myE {
my $a = '('.$1.')'.$3.'('.$2.')';
$a =~ s/\^/**/;
return eval($a);
}
while (<>) {
while (s/$WSb$num\s+$num\s+$op$WSa/' '.myE().' '/e) {}
print ($_, "\n");
}