Re: #t and #f now default to primitive types

[Per Bothner <per@bothner.com>]

On 04/02/2015 10:07 PM, Jamison Hope wrote:
> On Apr 2, 2015, at 9:27 PM, Per Bothner <per@bothner.com> wrote:
>
>> The literals #t and #f are now treated as having primitive boolean types,
>> rather than java.lang.Boolean type.  That is the return type of:
>>
>>     (define (neg x) (if (>= x 0) #f #t))
>>
>> is boolean rather than java.lang.Boolean.
>>
>> Of course you can specify Boolean explicitly if you want:
>>
>>     (define (neg x) ::java.lang.Boolean (if (>= x 0) #f #t))
>
> Thanks, Per.  I find it curious that with neg defined as above
> (returning primitive boolean), these return what they do:
>
> (define (f a b) (and (neg a) (neg b)))
> (define (g a b) (if (neg a) (neg b) #t))
> (define (h a b) (or (neg a) (neg b)))
> (define (i a b) (if (neg a) #t (neg b)))
>
> If everything is compiled all together in a module, f and g return
> java.lang.Boolean, h and i return primitive boolean.
>
>
> In the REPL, defining neg and then defining each of those four
> functions, they all return java.lang.Object.

I agree that's not very nice.  We can do better.  I need to ponder and
experimentmore.

> I still find the type inferencing to be a bit mysterious, I guess the
> actual return type of the neg function isn't always being queried when
> the IfExp's type is calculated?

I'm not sure yet.
-- 
	--Per Bothner
per@bothner.com   http://per.bothner.com/