[mercury-users] Fact tables

[Michael Day]

Hi,

To represent a relation that maps some ints to some other ints, which
would be the best Mercury implementation:

:- pred encoding(int, int).
:- mode encoding(in, out) is semidet.

:- pred encoding(int, maybe(int)).
:- mode encoding(in, out) is det.

:- pred encoding(int, int).		% returns -1 on failure (ugh)
:- mode encoding(in, out) is det.

The input does not form a contiguous range (although it may form multiple
independent contiguous ranges).

Would using the fact_table pragma affect the implementation, or just the
compilation speed? (presumably it would rule out using maybe(int)).

Thanks,

Michael

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