A Pointless Library Proposal

[Conor McBride]

David House wrote:
> On 31/10/06, Donald Bruce Stewart <dons at cse.unsw.edu.au> wrote:
>> But seems like we need a 'proper' solution. undefineds with lines
>> numbers, and errors with line numbers, would be a good start.
>
> I think it'd be nice to keep undefined around as a 'pure' bottom, and
> introduce a new value, say 'stub :: forall a. a' which is magic and
> sends the file and line location of its mention to stderr when
> executed.

As Haskell insists that bottom is a value, it's conceptually important 
to separate 'defined to be bottom' from 'not finished yet'. Never mind 
the run-time stub reports, we should have compile-time stub warnings 
which are as informative as possible about the task of instantiating the 
stub.

Cheers

Conor