iserv-proxy: iserv allows GHC to delegate Tempalte Haskell computations

GHC can be provided with a path to the iserv binary with -pgmi=pathto/iserv-bin, and will in combination with -fexternal-interpreter, compile Template Haskell though the iserv-bin delegate. This is very similar to how ghcjs has been compiling Template Haskell, by spawning a separate delegate (so called runner on the javascript vm) and evaluating the splices there.

iserv can also be used in combination with cross compilation. For this, the iserv-proxy needs to be built on the host, targeting the host (as it is running on the host). cabal install -flibrary -fproxy will yield the proxy.

Using the cabal for the target arch-platform-target-cabal install -flibrary will build the required library that contains the ffi startSlave function, which needs to be invoked on the target (e.g. in an iOS application) to start the remote iserv slave.

calling the GHC cross compiler with -fexternal-interpreter -pgmi=$HOME.cabalbin/iserv-proxy -opti<ip address> -opti<port> will cause it to compile Template Haskell via the remote at <ip address>.

Thus to get cross compilation with Template Haskell follow the following receipt:

• compile the iserv library for your target

iserv $ arch-platform-target-cabal install -flibrary

• setup an application for your target that calls the

• startSlave function. This could be either haskell or your

• targets ffi capable language, if needed.

 void startSlave(false /* verbose */, 5000 /* port */,
                 "/path/to/storagelocation/on/target");

• build the iserv-proxy

iserv $ cabal install -flibrary -fproxy

• Start your iserv-slave app on your target running on say 10.0.0.1:5000

• compiler your sources with -fexternal-interpreter and the proxy

project $ arch-platform-target-ghc ModuleContainingTH.hs \
            -fexternal-interpreter \
            -pgmi=$HOME/.cabal/bin/iserv-proxy \
            -opti10.0.0.1 -opti5000

Should something not work as expected, provide -opti-v for verbose logging of the iserv-proxy.