So many SML/NJ features are very poorly documented or their documentation is out of date. For my own sanity, I'm writing some tutorials (and maybe also documentation) for features that I find useful but that are very difficult to find documentation for.
- Pretty Printing: The SML/NJ REPL allows you to install custom pretty printers for monomorphic datatypes.
- Parsing: The SML/NJ Visible Compiler gives you access to a lot of compiler internals, including parsing. Here's a simple way to run the parser.