Hi GHC users, I'm looking for secure compile and run-time methods to ensure automatically that Haskell modules cannot perform particular IO operations. Therefore, I've got some questions that might be interesting for other people using GHC as well. o There are functions like "unsafePerformIO". How many of these unsafe functions exist and what are their names? Is there a possibility to tell GHC to reject programs in which such functions occur? Concerning, e.g., the rewrite-rule system, how can we prevent that these functions are applied by some trick, invisible by an automatic inspection of the source code? o Is the function "print" secure in the sense that all stuff it produces is restricted to go to stdout, even if strange sequences of control characters appear? o Is there a way to tell the GHC run-time system to block file operations or system calls coming from the application program, while permitting input/output via stdin/stdout? Thanks in advance -- Christoph Herrmann