Re: How to fight semideterminism in Mercury?

From: Bart Demoen (bmd_at_cs.kuleuven.ac.be)
Date: 10/18/04 

Date: Mon, 18 Oct 2004 10:46:29 +0200

Ralph Becket wrote:

> SOLUTION 2
>
> However, a simpler solution is to simply specify that your original
> add function always returns a non-empty AVL-tree:
[...]
>
> SOLUTION 3
>
> This is a bit of a hack, but if you stick to the if-then-else style

Ralph,

What you wrote seems to suggest that your solution 2 cannot be combined
with the if-then-else style without resorting to the hack. Is that true ?

You also wrote:

> Just as a point of style, it's usually preferable to use the built-in
> ordering function and a switch rather than if-then-elses:

Why is it preferable ? Is it shorter/clearer/conciser ... for the programmer ?
for any reader of the program ? Does the compiler do a better job in the
generated code ? Are more properties checkable by the compiler ? Are the
error messages better ?

Cheers

Bart