[MLton-user] Re: [polyml] Order of evaluation of arguments to a function

[Jeremy Dawson]

I recall reading somewhere (can't find it now) that Moscow ML is 
incorrect, but that it was done deliberately for efficiency reasons, the 
thinking being that it would be unlikely to be an issue in practice.

That is (as I recall), in f x1 x2 x3 (f not an application)
it will evaluate _all_ the arguments before evaluating _any_ of the 
applications

Peter - is this correct ?

Regards,

Jeremy Dawson

Ivan Tomac wrote:
> Is the following code supposed to print 1 followed by 2 or 2 followed by 1?
>
> val _ = (fn () => (print "1\n"; fn x => x)) () (print "2\n"; ())
>
> In SML/NJ, MLton and PolyML it does the former, while in Moscow ML it
> does the latter. Is this specified somewhere in the standard? I
> noticed equivalent code in OCaml behaves the way Moscow ML does which
> is not very surprising seeing how Moscow ML was based on Caml Light.
> Could this be a bug in Moscow ML?
>
> The following code works the same in all 4 SML compilers (but
> different in OCaml):
>
> val _ = (print "1\n"; 1) + (print "2\n"; 2)
>
> It seems to me like SML/NJ, MLton and PolyML evaluate all function
> arguments left to right, OCaml evaluates them right to left, and
> Moscow ML seems inconsistent.
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>   

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