Out-of-range decimal literals

Waldemar Horwat waldemar at google.com
Mon Sep 22 17:27:10 PDT 2008


Mike Cowlishaw wrote:
>>> Languages have "personalities", and people build up expectations based
>>> on these characteristics.  As much as possible, I'd like to suggest
>>> that ECMAScript be internally consistent, and not have one independent
>>> choice (binary vs decimal) have unexpected implications over another
>>> (signaling vs quiet operations).
>> The decimal literals introduces a new feature, a type suffix for a
>> number, to explicitly specify the type of the literal. It may well be
>> possible that this is not the last suffix to be added to ES. If, for
>> example, there would be a suffix to denote 32 bit int, it would be
>> very strange to allow to write 5000000000i. Another possibility is
>> support for exact binary floating point literals. Here again rounding
>> out-of-range literals would look strange as the programmer would
>> bother to write the number on purpose to get exact presentation.
> 
> For exact binary floating point literals there probably isn't a problem as 
> one would presumably use the hexadecimal format in IEEE 754 (the same as 
> in C) -- and it's fairly clearly an error if too may bits are specified 
> for the significand.  However, I suppose longer significands could be 
> allowed and rounded -- although that is very much against the concept of 
> exact literals.

Speaking of which, that one is required in IEEE 754r.  What is our implementation of it if we upgrade our reference from 754 to 754r?

    Waldemar


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