[m-dev.] Typecheck assertions

[Peter Ross]

Hi,

If you have an assertion of the form

:- assertion 
        (
                (some [AB] (app(A, B, AB), app(AB, C, ABC)))
        <=>
                (some [BC] (app(B, C, BC), app(A, BC, ABC)))
        ).

Is the following the best way to typecheck these assertions?

Create a new pred in the form:

assertion_a :-
        some [A,B,C,ABC] (
                (some [AB] (app(A, B, AB), app(AB, C, ABC)))
        <=>
                (some [BC] (app(B, C, BC), app(A, BC, ABC)))
        ).

and then typecheck that.

How hard will it be to generate meaningful error messages this way?

Pete.
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