[Template-haskell] Template Haskell progress

[John O'Donnell]

Dear CTHF (Cherished Template Haskell folk),

I can give quick replies to some of Simon PJ's questions:

1. I'm using TH in order to automate a program transformation needed
for Hydra, a computer hardware description language (CHDL) that is
embedded in Haskell.  More generally, I'm interested in the technology
of embedded implementations of "domain specific languages", and for that
reason I'm interested in exploring further what fits within the TH
view of things, and what doesn't.  There is a second language design
I'm involved with that may well also need TH; this is HaskTwoL, which
provides a mixture of task-parallelism and data-parallelism.

2. What went well?  I'm still in the early stages, but the good news is
that the Hydra transformations appear to be working.  There is a lot
still to do, and the system is incomplete and also fragile right now,
but so far it looks like TH is just the ticket.

More generally, two things helped me a lot: both Tim and Simon PJ were
very quick to respond to my queries, and that enabled me to get unstuck
and make some useful progress.  Thanks very much to both of you!  The
second thing was making the nightly builds available; it's great to
be able to experiment with the current system, without needing to
wait for a heavyweight release.

3. what (unfixed) bugs you found.  I encountered a bug that was already
reported by Sean Seefried, so I didn't report that one again.  Haven't
found any others yet, but there's always tomorrow...


The rest of Simon's questions are harder to answer; I'd rather wait
until I have a fully working prototype before deciding what the highest
priorities for me should be.  I don't want to say that "x is essential
and urgent, drop all else and do it" without a little more thought :-)

Cheers to the TH users as well as implementors,
John O'Donnell