[mercury-users] Pred defns

[Ralph Becket]

Fergus Henderson wrote on 31 Mar:
> 
> Yes, indeed.  And thank you for your proposal, I do think it is quite nice.
> I'm just trying to make it a bit more "O'Keefe-proof" ;-)

Let's just settle for flame retardant!

> I think Richard O'Keefe is right to object to the use of the same
> notation (capital letters) for two quite difference concepts
> (accumulators and logic variables).

Fair enough.  My personal preference is to introduce as little new
syntax as possible.  I may be coming round to the idea that named
accumulators a la EDCGs may be a good thing after all...

:- pred p(...) + [a:type1, ..., io:io__thread].
:- mode p(...) is something.

p(...) :-
	print("The answer to ") + [io],
	print($a) + [io],
	$a := $a + 1,
	print(" + 1 is ") + [io],
	print($a),
	...

Naaah.  This looks really gross.  I prefer the simpler notation after
all.


> 
> > A suggestion: why not decide upon a notation (if this proposal has
> > support) and provide a preprocessor.
> 
> By the way, if anyone wants to have a go at this, the file
> `samples/expand_term.m' is a good place to start.

Anyone got a student with nothing to do?

-- 
Ralph Becket  |  rwab1 at cam.sri.com  |  http://www.cam.sri.com/people/becket.html