[m-dev.] fact tables

[David Matthew OVERTON]

Fergus Henderson wrote:
> 
> Hi,
> 
> Currently fact tables (1) support only the types `int', `float', and `string'
> and (2) are not documented (some documentation was mailed to the
> mercury-developers mailing list, but was never committed).
> 
> A solution to (1) is not likely in the near future.
> 
> Given this, we have several options:
> 	(a) document them
> 	(b) add documentation for them to the .texi files, but leave
> 	    it commented out, until such time as (2) is solved
> 	(c) delete the support for fact tables
> 
> Opinions?
> 
Hi Fergus,

I don't think the support for fact tables should be removed from the
compiler.  They can be useful even though they currently support only
a few different types (I've used them for a couple of different things
and I believe Tom has too).  Also, they don't interfere with the
operation of any other part of the compiler.

I still have the .texi documentation I wrote.  The reason it was never
committed was that no-one could decide where it should go.  All other
documentation for pragmas, etc, is in the language reference manual,
but fact tables aren't an official part of the Mercury language.  
If you want documentation for fact tables, tell me where it should go
and I'll post a diff for it.

As for whether the documentation should be commented out or not, I
suppose it doesn't look very good to include visible documentation for
an unfinished feature.  But, given that the current implementation is
already useful for a wide variety of situations it might be a good
idea to let people know about it.


David
--
      David Overton              |  4th Year Software Engineering
 dmo at students.cs.mu.oz.au        |  Department of Computer Science
http://www.cs.mu.oz.au/~dmo/     |  The University of Melbourne