| I claim that the major thing that finalizers do is manipulate shared
| state.
That is certainly true. If they were pure, you'd never know they'd run!
| To get any benefit from writing finalizers in Haskell, I have to have
| MVars which protect against finalizers.
Nearly right, but not
| type MVar# s elt-- primitive
|
| newMVar#:: State# s - (# State# s, MVar# s elt #)
| takeMVar# :: SynchVar# s elt - State# s - (# State# s, elt #)
| putMVar#:: SynchVar# s elt - State# s - State# s
Bad idea to look at the primops. The important things are
Simon Peyton-Jones [EMAIL PROTECTED] writes:
| takeMVar# :: SynchVar# s elt - State# s - (# State# s, elt #)
| putMVar#:: SynchVar# s elt - State# s - State# s
Bad idea to look at the primops.
(a) It was the first mention of MVars that I found in the docs.
(b) I only really
| (a) It was the first mention of MVars that I found in the docs.
| (b) I only really mentioned it because the type sigs are wrong.
Hmm. That's not very clever.
| Doesn't it block if another thread manages to sneak a putMVar into
| the middle? Maybe I should read your Awkward Squad paper to
George Russell [EMAIL PROTECTED] writes:
it would normally be a good idea for implementations and programmers to
provide and use MVars, even if they do not provide and use concurrency,
... If NHC does not provide MVars, I think it should.
I don't think MVars make any sense without
On 11-Oct-2002, George Russell [EMAIL PROTECTED] wrote:
I think we should remember that the FFI standard has to address various
audiences
(1) those who want to implement portable code in just FFI + Haskell98.
This group does not have access to functions for conveniently manipulating
mutable
| To get any benefit from writing finalizers in Haskell, I have to have
| MVars which protect against finalizers.
Nearly right, but not quite. You might write a Haskell finalizer
that did lots of useful things (e.g. consulted a large pure data
structure) before doing its state-mutation by
Alastair Reid wrote:
[snip] I'm not sure I really understand the problem. The FFI
standard (Release Candidate 4, the one I have printed out here) does
not define IORefs, and of course Haskell 98 doesn't either.
Therefore, although this code is broken, this particular example
doesn't
For the record, I am strongly in favor of Haskell finalizers, if a
Mutable State extension were to be written, then it will have to address
the issue with one of the solutions mentioned in this thread, but among
other things, not having haskell finalizers seems to imply that we would
need to add
