Exceptions vs. Errors (Re: Readline read_history and
isaacdupree at charter.net
Thu Jan 24 13:56:06 EST 2008
>> It should really be:
>> block x = do
>> IO blockAsyncExceptions#
>> ret <- x
>> IO unblockAsyncExceptions#
>> return ret
>> in which case we could then supply implementations for
>> other monads as well.
> blockAsyncExceptions# has some tricks to restore tail-recursion in some
> cases (see the paper). But apart from losing that optimisation, I can't
> think of any reasons why the above couldn't work - one thing you have to
> worry about is what happens when x raises an exeption, but I think that
> is handled by the way we save and restore the blocked state in catch.
what about if the monad is a transformed one with its own error handling
methods (e.g. ErrorT IO) and so (IO blockAsyncExceptions#) is run but
(IO unblockAsyncExceptions#) is not? Is that a problem?
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