The following is an invalid µOCCAM program. This example tests variable assigments using three variables. It is invalid due to the last line as "yx" is an undeclared variable.
/public/cs3/web/ipptests/var-test1.reject
INT xy = 5: INT y.x = 10: INT a: SEQ xy := xy + 1 a := xy y.x := yx + 1