Proposal: overhaul System.Process

[Duncan Coutts]

On Sun, 2008-05-25 at 16:27 -0700, Frederik Eaton wrote:
> Hello,
> 
> I think it's great to improve System.Process, and the new interface looks
> good... I just wanted to say that I found it quite easy to write my own
> wrappers around those functions, which implement an interface that I find
> easier to use, several years ago. The hardest part was not so much writing
> the new interface, but updating it whenever the standard interface changed
> and broke my code. So I'd like to cast my vote for backwards compatibility.
> The standard libraries will never be perfect, but constantly deprecating and
> removing functionality can really impair their usefulness for large
> projects. I don't mean to be negative but I wanted to voice that concern.

The proposal is to deprecate several functions but not to remove
anything. The decision to remove anything is independent.

One this issue, one thing that I think may help is to have a period
where the deprecated functions still exist but are removed from the
documentation. The rationale is that one of the main reasons for
removing functions that are essentially duplicated by newer variants is
because they clutter the API docs.

So the deprecation cycle would be something like:

     1. normal
     2. deprecated and still documented
     3. deprecated and removed from documentation
     4. removed

Another thing that would help is if haddock marked deprecated functions
as such and kept them in a separate section of the index, at least in
the synopsis. It should be easy for haddock 2.x to find deprecated
functions since it can just look at the pragmas which are presumably
preserved by the GHC api.

Duncan