! Copyright (C) 2008 Chris Double. ! See http://factorcode.org/license.txt for BSD license. USING: kernel arrays strings math.parser sequences peg peg.ebnf peg.parsers memoize math accessors ; IN: peg.expr EBNF: expr number = ([0-9])+ => [[ string>number ]] value = number | ("(" exp ")") => [[ second ]] fac = fac "*" value => [[ first3 nip * ]] | fac "/" value => [[ first3 nip / ]] | number exp = exp "+" fac => [[ first3 nip + ]] | exp "-" fac => [[ first3 nip - ]] | fac ;EBNF