I imagine I have completely missed the boat on this one, but would like to test the waters on including the following [1] patch --------------------------------------------- Add hook for creating ghci external interpreter The external interpreter is launched by calling 'System.Process.createProcess' with a 'CreateProcess' parameter. The current value for this has the 'std_in', 'std_out' and 'std_err' fields use the default of 'Inherit', meaning that the remote interpreter shares the stdio with the original ghc/ghci process. This patch introduces a new hook to the DynFlags, which has an opportunity to override the 'CreateProcess' fields, launch the process, and retrieve the stdio handles actually used. So if a ghci external interpreter session is launched from the GHC API the stdio can be redirected if required, which is useful for tooling/IDE integration. ----------------------------- It is not behaviour-changing unless the hook is actually used, but does make a change to Hooks and hence DynFlags. I think it can potentially make a lot more options available for IDE tooling, and it would be great to have it available in GHC 8.0.x already. Alan [1] https://github.com/alanz/ghc/commit/6225d94056400c525a2b710aa31a74b5ea1d5f62