Thoughts on unified integer literal improvements

[Bruce Chapman]

Joe Darcy wrote:
> Hello.
>
> On the set of improved integer literal features, I think combining the 
> underscores as separators and binary literals is straightforward given 
> separately correct grammars for each change.
>
> As an alternate to "y" and "s" suffices, I suggesting considering a 
> "u" suffix to mean unsigned.  Literals with a trailing "u" would have 
> type int; widening conversions of such literals would 0 extend and 
> narrowing conversions would range check on the width of set bits.  For 
> example,
>
Doesn't that idea has some problems introducing it into the language and 
type system?

 if it is "Literals with a trailing "u" would have type int;" then the 
type is int, and the value just the same as for when there was no 
suffix. If the widening and narrowing changes behaviour for these 
literals only, how can this be done unless these literals are of some 
new type, or the type system knows about the notation used to declare 
the value?  And if we can have unsigned ints surreptitiously like this, 
then lets have unsigned byte as well, and unsigned byte arrays. Yeeha - 
now I'm really happy.   :)



But taking that idea, and combining it with the autosizing integer 
literal proposal such that we use the "u" suffix to denote autosizing 
(rather than only having it work for hex literals with the 0h prefix), 
now that might fly, and could work for decimal and octal and binary as well.

I'll have to do some more thinking thru on this, and now is not an ideal 
time for me.

> byte b = 0xABu // equivalent to (0xAB & 0xFF)
do you mean // equivalent to (byte) 0xAB  ? (because (0xAB & 0xFF) is 
already equivalent to 0xAB)
>
> long ell = 0xFFFFFFFFu; // A positive long value
but
int hell = 0xFFFFFFFFu; // -1  ???
>
> I think this approach has some advantages over the "y" suffix; in 
> particular I think it gives more desirable behavior in cases like this:
>
> byte b = 0xFFy // a negative byte value
> byte b = 0xFFu // also a negative byte value
>
>
> short s = 0xFFy // a negative short value, -128;
>                 // byte value is signed extended
> short s = 0xFFu // a positive short value, +127
do you mean // a positive short value, +255?

>
> int   i = 0xFFy // -128
> int   i = 0xFFu // 127
>
> -Joe
>
Bruce