[Haskell-cafe] Newbie: Is it possible to catch _|_ ?

Russ Lewis spamhole-2001-07-16 at deming-os.org
Tue Apr 6 13:47:46 EDT 2004

Oh.  I was figuring that the runtime would detect _|_ whenever 
evaluation requires that it calculate a given expressoin, and that 
expression is currently being evaluated...that is, some subset of an 
expression evaluates to the expression itself.

Now that you mention it, I guess there are a lot of other nonterminating 

Thanks for the prompt response!

Russ Lewis
    Experienced imperative programmer, functional newbie :)

Ketil Malde wrote:

>"Russ Lewis" <spamhole-2001-07-16 at deming-os.org> writes:
>>Another newbie question: Is it possible to catch _|_ - that is, to
>>encounter it, handle it and continue?
>Since _|_ is the value of a non-terminating computation, this requires
>you to solve the halting problem.  GHC does occasionally detect loops,
>but for the general case, don't hold your breath :-)

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