[jhc] Atoms, Infos and unique ids.

John Meacham john at repetae.net
Thu Feb 21 18:53:26 EST 2008

On Fri, Feb 22, 2008 at 12:13:10AM +0100, Lemmih wrote:
> On Thu, Feb 21, 2008 at 11:23 PM, John Meacham <john at repetae.net> wrote:
> >  If you want crazy obfuscated code in pursuit of performance, look at
> >  ghc. at least I try to stay mostly haskell 98 (well, haskell-prime beta
> >  is actually what I target). avoiding things like explicit unboxed types
> >  and try to keep all strangeness encapsulated behind abstract types with
> >  well defined interfaces. ghc lobs around Int#'s like candy :)
> I wanna make a quick response to this segment because I actually feel
> slightly insulted. I'm trying to get rid of a global mutable state and
> some C code that segfaults if used incorrectly, and you're accusing me
> of obfuscating the code? 

Oh, no, I didn't mean to imply that at all. I _really_ appreciate the
work you are putting in to making jhc faster. what I meant to say is
that I know parts of jhc are _already_ obfuscated, but that as far as
haskell compilers go, it's not as bad as it could be. :)

As in, I endevour to make sure the APIs are clean and well founded. that
is what really matters when it comes to maintainability of code. The Id
implementation can be swapped out willy nilly once it is fully
abstracted, so worrying about how it actually is implemented seems
premature. In the end, once the APIs are stable, it is easy enough to
plug in a variety of implementations and just try em all out. That
should be true of any component of jhc if I did my design right.

> I'm proposing to associate names directly
> with variables instead of using a magic pointer. It would be the
> natural thing to do, completely valid Haskell98 code, and several
> times faster than the current approach.

Hmm... are you sure it would be faster? perhaps I don't fully understand
what you want to do, but Atoms were darn fast when I was benchmarking, I
could have broken them though. I mean, perhaps the speed benefit isn't
that useful for jhc... I use the same atom implementation in C projects
but I enjoy that in haskell-land I can hide the implementation behind a
newtype to make them fully safe. I heart haskell.


John Meacham - ⑆repetae.net⑆john⑈

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