ast.Rule:
  Name:
    ast.Ident:
      Name: expr
  Expr:
    ast.BinaryExpr:
      X:
        ast.Ident:
          Name: termExpr
      Op: %
      Y:
        ast.Choice:
          Options:
            ast.BasicLit:
              Kind: STRING
              Value: "+"
            ast.BasicLit:
              Kind: STRING
              Value: "-"
ast.Rule:
  Name:
    ast.Ident:
      Name: termExpr
  Expr:
    ast.BinaryExpr:
      X:
        ast.Ident:
          Name: unaryExpr
      Op: %
      Y:
        ast.Choice:
          Options:
            ast.BasicLit:
              Kind: STRING
              Value: "*"
            ast.BasicLit:
              Kind: STRING
              Value: "/"
ast.Rule:
  Name:
    ast.Ident:
      Name: unaryExpr
  Expr:
    ast.Choice:
      Options:
        ast.Ident:
          Name: operand
        ast.Sequence:
          Items:
            ast.BasicLit:
              Kind: STRING
              Value: "-"
            ast.Ident:
              Name: unaryExpr
ast.Rule:
  Name:
    ast.Ident:
      Name: operand
  Expr:
    ast.Choice:
      Options:
        ast.Ident:
          Name: INT
        ast.Ident:
          Name: FLOAT
        ast.Sequence:
          Items:
            ast.BasicLit:
              Kind: STRING
              Value: "("
            ast.Ident:
              Name: expr
            ast.BasicLit:
              Kind: STRING
              Value: ")"