module Expressions

imports
  basic/Whitespace
  basic/IdentifierCon

exports

  sorts Exp

  lexical syntax
    [0-9]+ -> IntConst
    [a-zA-Z][a-zA-Z0-9]* -> Id

  context-free syntax
    IntConst    -> Exp {cons("Int")}
    Id          -> Exp {cons("Var")}
    Exp "+" Exp -> Exp {left, cons("Add")}
    Exp "*" Exp -> Exp {left, cons("Mul")}
    "(" Exp ")" -> Exp {bracket}

  context-free priorities
    Exp "*" Exp -> Exp >
    Exp "+" Exp -> Exp