[Haskell-cafe] Re: Why purely in haskell?

jerzy.karczmarczuk at info.unicaen.fr jerzy.karczmarczuk at info.unicaen.fr
Thu Jan 10 19:57:54 EST 2008


ajb at spamcop.net writes: 

> A "black hole" is what happens when evalation of something recursively
> depends on its own evaluation in such a way that no useful work can be
> done.  An example is: 
> 
>     let omega = omega + 1 in omega 
> 
> In previous GHCs, that triggered am error which used the phrase "black
> hole".  Now, I think it just consumes the heap and/or stack.  On my
> 2005-era Hugs, it causes a seg fault.

Strange, because blackohes are visible by the runtime.
Clean should say: "Warning, cycle in spine detected", and stop. 

Jerzy Karczmarczuk 

PS. Perhaps Simon decided to think more literally about the black hole
   as it is in the theory of relativity?
   You know, when you descend a probe into it, and look from a faraway,
   safe distance, it takes an infinite amount of time for the probe to
   reach the event horizon... 




More information about the Haskell-Cafe mailing list