(definst set (stream :export t) (var expr)
(format stream "~@<~A = ~@_~2I~A;~:>" var expr))
(definst update (stream :export t) (var op expr)
(definst set (stream :export t) (var expr)
(format stream "~@<~A = ~@_~2I~A;~:>" var expr))
(definst update (stream :export t) (var op expr)