# This version of expr.tok does also accept for whitespace between tokens. Factor : @{ Int _ # built-in 64-bit signed integer token '(' _ Expr ')' _ } Term : @{ Term '*' _ Factor $1 * $4 Term '/' _ Factor $1 / $4 Factor } Expr : @{ Expr '+' _ Term $1 + $4 Expr '-' _ Term $1 - $4 Term } Expr