Nomsu's only dependencies are [Lua 5.2 or later](https://www.lua.org/) (tested with version 5.2.4) (or [Luajit](http://luajit.org/) (tested with version 2.1.0)) and [LPEG](http://www.inf.puc-rio.br/~roberto/lpeg/) (`luarocks install lpeg`). Nomsu's compiler was written in [Moonscript](http://moonscript.org/), but all of the .moon files have been compiled into lua for convenience, so Moonscript is not a dependency.
* (Advanced/optional) To precompile a .nom file into lua, run `lua nomsu.lua -c <input_file>` to precompile your file into lua (by default, saved in the same location, but with a `.lua` extension instead of `.nom`). If you run the compiler with the "-O" (for Optimized) flag, the compiler will run the precompiled lua files directly, instead of parsing and compiling the .nom files before running them. This is not necessary, but it can speed things up if you precompile a bunch of code that involves macros or compile-time activity.
If you enjoy Nomsu so much that you'd like to tinker with it or have it in your system path, there is an included Makefile. This is entirely optional, but you can run `make` to compile any modified .moon or .nom files into .lua files and produce an executable file called `nomsu` that can be run directly. `make test` will run the suite of tests. `make install` will install the compiler on your system. By default, the `nomsu` executable will be put in `/usr/local/bin` and all the necessary support files will be put into `/usr/local/share/nomsu/*`, but you can change the location with `make PREFIX=/your/path/here install` (or `NOMSU_BIN_DIR` and `NOMSU_LIB_DIR` to specify them separately). The default build options use the system default `lua`, but this can be changed via `make LUA=luajit` or `make LUA_BIN=/path/to/lua`. To uninstall, simply `make uninstall` with the same flags you used to install.
## File Layout
All `.moon` files have been precompiled into corresponding `.lua` files, so you don't need to have [Moonscript](http://moonscript.org/) installed to run the Nomsu compiler.
*`nomsu` - A shell script that selects between different installed versions of Nomsu (using the `-V` flag). You can use this script to, for example, run `nomsu -V 1.2 your_script.nom` to run with the latest version of Nomsu that matches `1.2.?.?`. All flags and arguments are passed along to whichever Nomsu compiler is chosen.
*`nomsu.moon` - The source code for the Nomsu command line runner. This handles launching the compiler and running the REPL.
*`nomsu.peg` - The [Parsing Expression Grammar](https://en.wikipedia.org/wiki/Parsing_expression_grammar) used to define Nomsu's syntax. The format of this file is a slightly modified version of the format accepted by LPEG's `re` module.
*`nomsu_compiler.moon` - **The actual Nomsu compiler**. This file can be imported and used without going through the regular command line interface (e.g. for applications that want to embed the compiler).
*`parser.moon` - The Nomsu parser. This file can also be imported and used directly for applications that only need to *parse* Nomsu, not compile it.
*`nomsu_tree.moon` - Datastructures used for Nomsu ASTs.
*`code_obj.moon` - Datastructures used for incrementally building generated code, while preserving code origins.
*`error_handling.moon` - The logic for producing good error messages within Lua that reference the Nomsu source code that led to them.
Nomsu uses the following versioning scheme: `[syntax version].[core library API version].[compiler internal API version].[lib/ API version]`. Which means:
* Any code that parses on `Nomsu X.a.b.c.d` will also parse on Nomsu `X.p.w.r.s`
* Any code that compiles on Nomsu `X.Y.a.b.c` will also compile on Nomsu `X.Y.p.q.r` and run without any differences, as long as it only depends on the behavior of the core library functions (i.e. stuff defined in `core/*.nom`), and doesn't mess with the compiler internals at all.
* Any code that compiles on Nomsu `X.Y.Z.a.b` will also compile on Nomsu `X.Y.Z.p.q` and run without any differences, even if it messes with the compiler internals, as long as it doesn't use anything from `lib/*.nom`.
* Any code that compiles on Nomsu `X.Y.Z.W` will also compile on any other Nomsu `X.Y.Z.W` and run without any differences, even if it uses stuff from `lib/*.nom`.
When Nomsu is istalled via `make install`, all of Nomsu's lua files and `core/*.nom` and `lib/*.nom` files are stored in `$PREFIX/lib/nomsu/$NOMSU_VERSION` and the Nomsu executable is installed to `$PREFIX/bin/nomsu$NOMSU_VERSION`, along with the file `nomsu` (the version-selection script), which goes to `$PREFIX/bin/nomsu`. When `make uninstall` is run, all those files are deleted (except for `nomsu`, if there are other versions installed).
There is a vim plugin for the language available in the [Vim Nomsu repository](https://bitbucket.org/squidarms/vim-nomsu/src). It is usually kept relatively up-to-date with Nomsu, but occasionally lags behind.
