Re: Documentation of Lua modules at https://github.com/arcapos/

[Sean Conner <sean@...>]

It was thus said that the Great Marc Balmer once stated:

> Many of the Lua modules we wrote from scratch or adapted from existing
> software are published as open source software on
> https://github.com/arcapos/ <https://github.com/arcapos/>.  They are all
> maintained and in wide use in our commercial products (mostly point of
> sale and online systems).  They lacked, however, documentation in most
> cases.

  I'm reading the code for UUID: https://github.com/arcapos/luauuid/blob/master/luauuid.c
and I was struck by an odd choice.  The code goes:

	struct luaL_Reg uuid_methods[] = {
		{ "clear"   , lua_uuid_clear },
		{ "compare" , lua_uuid_compare },
		...
	};

	if (luaL_newmetatable(L,UUID_METATABLE)) {
		luaL_setfuncs(L,uuid_methods, 0);

		...

		lua_pushliteral(L,"__eq");
		lua_pushcfunction(L,lua_uuid_equal);
		lua_settable(L,-3);

		...
	}

  Why not just list the metamethod functions in uuid_methods[]?

	struct luaL_Reg uuid_methods[] = {
		{ "__eq"       , lua_uuid_equal },
		{ "__lt"       , lua_uuid_less },
		{ "__le"       , lua_uuid_less_or_equal },
		{ "__gc"       , lua_uuid_clear },
		{ "__tostring" , lua_uuid_unparse },
		{ "__concat"   , lua_uuid_concat },
		{ "__len"      , lua_uuid_length },
		{ "clear"      , lua_uuid_clear },
		{ "compare"    , lua_uuid_compare },
		...
	};

  Saves some code.  You still have to push the __index and __metatable
fields, but the functions can be set along with the other functions.

  And because it hurts me to have to type

	syslog('warning',string.format("Unit %d is at %s",unit,status))

you can have the syslog function call format for you:

	static int
	unix_syslog(lua_State *L)
	{
		luaL_checktype(L,1,LUA_TSTRING);
		lua_getfield(L,2,"format");
		lua_insert(L,2);
		lua_call(L,lua_gettop(L) - 2,1);
		syslog(priorities[luaL_checkoption(L,1,NULL,priority_names)],"%s",lua_tostring(L,-1));
		return 0;
	}

> fwiw, I have put the documentation of these modules online at
> https://lua.msys.ch/ <https://lua.msys.ch/>, our microsite for Lua related
> stuff.  Also on this site you will find a work in progress, the "Lua
> Integration Guide", where we try to collect and share our experiences
> while integrating Lua in existing software, write Lua bindings to existing
> libraries etc.  We put it online in the hope it is helpful for some folks.

  Very cool!

  -spc
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