Re: datatype constructor as syntax

19/03/14 19:16, Matthew Fluet wrote:
> On Tue, Dec 31, 2013 at 3:47 AM, Florian Weimer <[email protected]> wrote:
>> * Henry Cejtin:
>>
>>> Sorry,  I  thought  I  was  being  clever,  but  if  you look at Andreas
>>> Rossberg's Defects in the Revised Definition of Standard ML
>>>      http://www.ps.uni-saarland.de/Publications/documents/Rossberg_DefectsSML.pdf
>>> you will see that he points out that rule 126 of the  dynamic  semantics
>>> implies  that  this  should really give you a bind exception at runtime.
>>> This was fixed (meaning you get the in MLton way back in 2001 to give an
>>> error at compile time.
>>
>> Curiously, the fun-based approach
>>
>>    datatype mytype = foo | bar of int
>>    fun bar _ = ()
>>    val bar = 23
>>
>> still runs without raising an exception when compiled with MLton.
>
> That seems to be an oversight.

Perhaps I missed the point here but I'm hoping that it's intentional 
that MLton allows the status of a constructor id to be overwritten by a 
fun binding.  I am relying on code as follows to create a value NONE:

   local
     fun NONE () = <expression>
   in
     val NONE = NONE ()
   end

Note that this does not create an unreferenced id, which avoids spurious 
warnings from such checks, for example, using Poly/ML with
   PolyML.Compiler.reportUnreferencedIds := true;

If this isn't allowed, how should a value called NONE be created?

Phil

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