Now that the C++ generator no longer overrides genVariable', it seems wise to remove it from the GenOps function dictionary.
You can call it via either genVariable or genVariableUnchecked anyway, so genVariable' is just used by the two former functions as implementation. It can easily be put back into the dictionary later on, if that turns out to be necessary.
This was not as straightforward as the C++ backend. CIF has no capability for supporting waiting *for* a specified time as an ALT guard; only waiting until (AFTER, in occam) a specified time. This is further complicated by the fact that when you disable an ALT timer guard in CIF, you have to be able to supply the timeout value that you waited on in the enable sequence.
Therefore, I added a pass that transforms all WaitFor guards into WaitUntil guards, by declaring nonce time variables, getting the time, and adding on the delay that we want to wait for; these actions occur just before the ALT.
This new pass is in the new BackendPasses module, into which I also moved the identifyParProcs pass. I also wrote tests for my new pass that live in the new BackendPassesTest module.
ErrorReport is of type (Maybe Meta, String), thereby adding an optional code position to error messages.
Die has been changed so that die and dieP are now implemented in terms of dieReport (:: ErrorReport -> m a). This involved changing less code than changing die to be of type ErrorReport -> m a. All that had to be changed directly was that Die instances now implement dieReport instead of die.
Any bits of code that "caught" errors has been changed so that it handles ErrorReport instead of String. This ErrorReport is eventually, in Main, passed to dieIO, which will soon be changed to read the file in and provide the context. Accordingly, MonadIO m has been added as a constraint to dieIO, and dieInternal has been changed to no longer use dieIO (because really we can't add the MonadIO constraint to dieInternal).
Various error messages have been changed. Notably, all instances of fail in ParseOccam have been changed to use die or, wherever possible, dieP. A similar thing has been done in EvalConstants and EvalLiterals.
The function showCode shows code as either occam or Rain depending on the frontend. This is then used by a formatCode function that acts similar to
printf, which makes it easy to format error messages that use showCode.
These declarations are necessary for recursive functions/procs, so that the (forward) declarations are visible to the implementations.
Later on, the declarations could be moved into header files, which would allow multiple source files to be compiled (generating multiple header files) and linked together using the gcc linker. Alternatively, external C/C++ programs could use code originally written in occam/Rain by including the header files.
