Hi, I'm trying to come to grips with GHC, and one thing that I think would help would be a nice guide to the Core and STG syntaxes. There is an old guide to Core syntax in the user guide (section 4.17.3) but that section remains unchanged from at least version 0.29 of the compiler, and is looking rather out of date. "Implementing lazy functional languages on stock hardware: the spineless tagless G-machine" has a good overview of the STG language, but it too is out of date and/or simplified. The document fptools/ghc/docs/rts/rts.tex has a section for STG syntax, but it's empty and marked with "ToDo". The syntax spat out by GHC at various stages when -v4 is enabled seems to vary somewhat, and it's also slightly different to that emitted to .hcr files when the -fext-core option is on, all of which makes things a bit confusing. Does anyone know where I can find up-to-date information about these intermediate representations? Thanks. -- Nick Nethercote njn25@cam.ac.uk