Recovering from stack overflow or heap exhaustion in a Haskell program

Question

I am currently writting a genetic algorithm in Haskell in which my chromosomes are rather complex structures representing executable systems.

In order for me to evaluate

Answer 1

This will be hard to do reliably from inside Haskell -- though under some conditions GHC will raise exceptions for these conditions. (You will need GHC 7).

import Control.Exception

If you really just want to catch stack overflows, this is possible, as this example shows:

> handle (\StackOverflow -> return Nothing) $
              return . Just $! foldr (+) 0 (replicate (2^25) 1) 
Nothing

Or catching any async exception (including heap exhaustion):

> handle (\(e :: AsyncException) -> print e >> return Nothing) $
              return . Just $! foldr (+) 0 (replicate (2^25) 1) 
stack overflow
Nothing

However, this is fragile.

Alternately, with GHC flags you can enforce maximum stack (or heap) size on a GHC-compiled process, causing it to be killed if it exceeds those limits (GHC appears to have no maximum stack limit these days).

If you compile your Haskell program with GHC (as is recommended), running it as:

$ ghc -O --make A.hs -rtsopts 

the low heap limit below is enforced:

$ ./A +RTS -M1M -K1M
Heap exhausted;

This requires GHC. (Again, you shouldn't be using Hugs for this kind of work). Finally, you should ensure your programs don't use excessive stack in the first place, via profiling in GHC.