Re: mark uniqueness

[Andy Wingo]

On Wed 25 Jan 2012 01:26, Mark H Weaver <address@hidden> writes:

> Andy Wingo <address@hidden> writes:
>
>>   (define-syntax-rule (define-const x val)
>>     (begin
>>       (define t val)
>>       (define-syntax x (identifier-syntax t))))
>>
>> Here, `t' will have a fresh mark.
>>
>> Now, if in one compilation unit, I do:
>>
>>   (define-const x 10)
>>
>> And in another, I do:
>>
>>   (let ((t 20))
>>     x) => ?
>>
>> You would expect the result to be 20.  But I think it could be 20, if
>> the marks on the two "t"s happened to collide.

FWIW I think this example wasn't quite right; you'd need to have the
case where both "t"s that are visible have marks.  Like in compilation
unit B:

  (let ()
    (define-const y 20)
    x) => ?

Cheers,

Andy
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