Unit unboxed tuples

[Duncan Coutts]

On 23 December 2011 20:09, Stefan Holdermans <stefan at vectorfabrics.com> wrote:
>> Here are the kinds of the type constructors:
>>
>>                 (,,) :: * -> * -> * -> *
>>                 (,) :: * -> * -> *
>>                 () :: *
>>
>>                 (# ,, #) :: * -> * -> * -> #
>>                 (# , #) :: *  -> * -> #
>> BUT
>>                 (#  #) :: * -> #
>
> Just of out curiosity, what would be a compelling use case for singleton and unit unboxed tuples?

For singleton unboxed tuples, any situation where you want to return a
single value but not force its evaluation. This occurs for example
with some low level functions in the implementation of ordinary lazy
arrays.

Duncan