alex:

eBay modifies 30k lines of code per week while maintaining 99.92% uptime.

Is there a way to force ghc (or some other Haskell implementation) to load new implementations of functions without restarting the program?

Alternatively, is there a way of restarting a program with new code without having to reconstruct all its in memory state?

You could consider using hs-plugins: http://www.cse.unsw.edu.au/~dons/hs-plugins/ the example at the bottom of http://www.cse.unsw.edu.au/~dons/hs-plugins/hs-plugins-Z-H-7.html#node_sec_6... shows how to load a new object into a running program, changing an already existing function on the fly. This uses GHC's dynamic linker underneath. -- Don