[m-dev.] Ordered conjunction

[Robert Jeschofnik]

On 25-Aug-2000, Fergus Henderson <fjh at cs.mu.OZ.AU> wrote:
> On 24-Aug-2000, Erwan Jahier <Erwan.Jahier at irisa.fr> wrote:
> > Ralph Becket <rbeck at microsoft.com> writes:
> > 
> > > I know this has come up before, but I just want to restate the case
> > > for an ordered conjunction (P && Q) which constrains the compiler to
> > > call P before Q (for && pick the symbol of your choice).
> > 
> > What about `then'? It seems to me that it a degenerated case of
> > if-then-else where there is no `else' branch (or where the `else'
> > branch it equivalent to `fail').  
> 
> You're right about the semantics of `P && Q' being the same
> as `if P then Q else fail' or `P -> Q ; fail'.

What about scoping, though?

In `(P -> Q ; fail), R' I'm not allowed to use variables that are bound inside
P, instead they must be bound inside Q.

It would not make much sence to enforce this same restriction on `P && Q, R'.


Rob
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