Luar: Lua reflection bindings for Go

Luar is designed to make using Lua from Go more convenient. Go structs, slices and maps can be automatically converted to Lua tables and vice-versa. The resulting conversion can either be a copy or a proxy. In the latter case, any change made to the result will reflect on the source.

Any Go function can be made available to Lua scripts, without having to write C-style wrappers.

Luar support cyclic structures (map[string]interface{}, lists, etc.).

User-defined types can be made available to Lua as well: their exported methods can be called and usual operations such as indexing or arithmetic can be performed.

See the documentation for usage instructions and examples.

Installation

Install with

go get <repo>/luar

Luar uses Alessandro Arzilli's golua. See golua's homepage for further installation details.

REPL

Version 1.x features an example REPL that is available in the cmd folder.

Run tests

go test -ldflags "-v -L ../vxcommon/lib/mingw32 -extldflags '-Wl,--export-all-symbols \
-Wl,--whole-archive ../vxcommon/lib/mingw32/libluab.a -Wl,--no-whole-archive \
-lgdi32 -lmsimg32 -lopengl32 -lwinmm -lws2_32 -lole32 -lluajit -lstdc++'" -v ./...

Changelog

Luar 2

This is a rewrite of 1.x with extended features and a cleaner API. The main differences with the previous version:

• The function prototypes of GoToLua and LuaToGo are simpler and do not require the use of reflection from the callers. The dontproxify argument is gone, use GoToLuaProxy to control proxification.

• The Copy* functions and GoLuaFunc are gone, use GoToLua and LuaToGo instead.

• Use Register instead of RawRegister.

• InitProxies is gone since it was not needed.

• The LuaObject and LuaTableIter structure fields are unexported.

• LuaObject methods not only work on Lua functions but also on anything with a __call metamethods. Idem for tables and the __index/__newindex metamethods.

• Use NewLuaObjectFromName(L, "_G") instead of Global.

• Lookup and Geti gone. Instead the Get and GetObject functions are variadic: each subfield argument can be any valid Lua key (string, integer...).

• Use (*LuaObject) Call instead of (*LuaObject) Callf. The protoype of (*LuaObject) Call has changed in a fashion similar to GoToLua and LuaToGo. Types is gone as it is no longer needed.

• Register ProxyIpairs and ProxyPairs instead of calling LuarSetup.

• Register and use Unproxify instead of ArrayToTable, MapToTable, ProxyRaw, SliceToTable and StructToTable.

• ComplexReal and ComplexImag have been replaced by the proxy attributes real and imag, respectively.

• SliceSub and SliceAppend have been replaced by the proxy methods slice and append, respectively. Slice proxies have the cap metamethod alongside append and slice.

• String proxies have a slice method just like slice proxies. They can be looped rune-by-rune over with ipairs.

The range of supported conversion has been extended:

• LuaToGo can convert to interfaces and pointers with several levels of indirection.

• LuaToGo can convert to non-empty maps and structs.