Questions on number constraints and conversions

Lars T Hansen lth at
Mon Sep 3 05:40:29 PDT 2007

On 6/5/07, liorean <liorean at> wrote:
> Hello!
> After discussion in a thread on ECMAScript binding of the DOM I came
> to wonder a bit of what type of type contraints ES4 actually will be
> able to have:
> 2. Also, conversions between the types. Is is possible to have a type
> constraint of uint that does not wrap around negatives but instead
> throws if the value is not part of the value set of uint for example?
> Similarly a type constraint of int and a value larger than 0x7fffffff
> throwing instead of of wrapping around into the negatives?

Nothing's been discussed, really.  Generally the number types are
interconvertible and truncation etc can be hard to control.  You could
imagine a type constructor, eg "strict", s.t.

  var x : strict int

means x can only convert from the value set implied by int.  For
example.  But almost certainly not in ES4.


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