[mercury-users] Prolog

[Ralph Becket]

Fergus Henderson, Thursday, 13 March 2003:
> On 11-Mar-2003, suja c <suja_cin at yahoo.com> wrote:
> 
> > Does mercury support the repeat predicate of
> > prolog? What is the equivalent for that in Mercury.
> 
> In Prolog, "repeat" is used for failure-driven loops.  As it says in
> the transition guide, "failure-driven loops in Prolog programs should
> be transformed into ordinary tail recursion in Mercury".

The following is also an (unfortunately) common Prolog idiom

	(
		generate(...),		% nondet
		test(...),		% semidet
		do_some_io(...),	% det
		fail
	;
		true
	)

You can do this sort of thing purely declaratively using
unsorted_aggregate or do_while from the std_util Mercury standard
library module.

	Ralph
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