Error Handling for Parameterized Data Types

The merit and the problems of the initial algebra approach to data type specification are widely discussed (e.g. [ADJ 78], [EKTWW84] , [EKMP 82], [Or 82]), a prevailing view being that the foundations are settled enough to define specification languages based on this approach [EFH 83]. We somewhat disagree with this view, not so much as we favour other approaches [SW 83], [BG 80], [M.V 83] — in fact we believe that the initial algebra approach has the advantage clearly to distinguish between syntactical constructions and correctness criteria on the semantical level — but for reasons being inherent in the method.