{
    "comment": "Grammar showing precedence operators and semantic actions.",

    "lex": {
        "rules": [
           ["\\s+", "/* skip whitespace */"],
           ["[0-9]+", "return 'NAT';"],
           ["\\+", "return '+';"],
           ["\\*", "return '*';"],
           ["$", "return 'EOF';"]
        ]
    },

    "tokens": "NAT + * EOF",
    "operators": [
        ["left", "+"],
        ["left", "*"]
    ],
    "bnf": {
        "S" :[[ "e EOF",   "return $1;"  ]],
        "e" :[[ "e + e",   "$$ = [$1,'+', $3];" ],
              [ "e * e",   "$$ = [$1, '*', $3];" ],
              [ "NAT",     "$$ = parseInt(yytext);" ]]
    }
}