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lua bindings

 
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clayasaurus



Joined: 21 May 2004
Posts: 857
PostPosted: Mon Mar 28, 2005 12:53 pm    Post subject: lua bindings Reply with quote
added initial lua bindings to the trunk.

they are not perfect, but they are a good start : )

if you find something wrong with them, feel free to change them.

www.lua.org

edit: updated the bindings to use typedef instead of alias for lua_CFunction and other function definitions.

Last edited by clayasaurus on Thu Dec 22, 2005 6:38 pm; edited 2 times in total
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clayasaurus



Joined: 21 May 2004
Posts: 857
PostPosted: Wed Mar 30, 2005 12:26 am    Post subject: Reply with quote
sample function implementation

Code:

import lua.lua,
       lua.lauxlib,
       lua.lualib;
       
import std.stdio, std.date;       
       
/* the Lua interpreter */
lua_State* L;

int luaadd ( int x, int y )
{
   int sum;

   /* the function name */
   lua_getglobal(L, "add");

   /* the first argument */
   lua_pushnumber(L, x);

   /* the second argument */
   lua_pushnumber(L, y);

   /* call the function with 2
      arguments, return 1 result */
   lua_call(L, 2, 1);

   /* get the result */
   sum = cast(int)lua_tonumber(L, -1);
   lua_pop(L, 1);

   return sum;
}


extern(C)
{
static int average(lua_State *L)
{
   /* get number of arguments */
   int n = lua_gettop(L);
   double sum = 0;
   int i;

   /* loop through each argument */
   for (i = 1; i <= n; i++)
   {
      /* total the arguments */
      sum += lua_tonumber(L, i);
   }

   /* push the average */
   lua_pushnumber(L, sum / n);

   /* push the sum */
   lua_pushnumber(L, sum);

   /* return the number of results */
   return 2;
}

static int dtime(lua_State *L)
{
   d_time time = getUTCtime();
   
   char *str = toDateString(time);
   
   lua_pushstring(L, str);
   
   return 1;
}
}

int main (  )
{
   /* initialize Lua */
   L = lua_open();

   /* load Lua base libraries */
   lua_baselibopen(L);

   /* register our function */
   lua_register(L, "average", cast(lua_CFunction)&average);
        lua_register(L, "dtime", cast(lua_CFunction)&dtime);

   /* run the script */
   lua_dofile(L, "test.lua");

   sum = luaadd(2,2); // makes sum = 4
   writefln("sum is ", sum)

   /* cleanup Lua */
   lua_close(L);

   return 0;
}


test.lua

Code:

print("hello lua world...")

-- test2
function add ( x, y )
   return x + y
end

-- test3
avg, sum = average(10, 20, 30, 40, 50)

print("The average is ", avg)
print("The sum is ", sum)

time = dtime()

print("The time is ", time)


results...

hello lua world...
The average is 30
The sum is 150
The time is Wed Mar 30 2005
sum is 4
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xammy



Joined: 01 Feb 2007
Posts: 6
Location: Magdeburg, Germany
PostPosted: Wed Jul 23, 2008 1:57 pm    Post subject: Lua library Reply with quote
I've done some work on a Lua library with the following features:

* lua states and buffers are wrapped in OOP style.
* protected calls are made exception safe and the call chain-information in put into the exception trace. using standard C lua, the app would segfault on exception, because of setjmp () and getjmp () in the lua lib itself.
* you can register functions, methods and class-constructors directly to a given LuaState via a mixin.

This reduces the given example to the following code (using Tango, but that's only interesting for Date/Time and I/O stuff:

Code:
import lua.all;
import tango.io.Stdout, tango.text.locale.Locale, tango.time.Clock;

LuaState state;

int luaadd (int x, int y)
{
   int sum;

   state.getGlobal("add"); // push the internal lua add function 
   state.pushNumber (x); // push x
   state.pushNumber (y); // push y
   state.call (false, 2, 1); // do an unprotected call, push 2 arguments and expect 1 result

   sum = state.toInteger (-1); // get the result
   state.pop ();

   return sum;
}

int average (LuaState L)
{
   int n = L.getTop ();
   double sum = 0.0;
   int i;

   for (i = 1; i <= n; i++)
   {
      sum += L.toNumber (i); // add each
   }
   
   L.pushNumber (sum / n); // push the average
   L.pushNumber (sum); // push the sum

   return 2; // number of return values
}

int dtime (LuaState L)
{
   auto locale = new Locale;
   L.pushString (locale ("{:ddd MMMM dd yyyy}", Clock.now));
   return 1;
}

int main (char[][] args)
{
   state = new LuaState (); // creates state and loads BASE module.

   // we register both D functions in lua
   mixin (mixinLuaRegisterFunction ("state", "Test.average", "average"));
   mixin (mixinLuaRegisterFunction ("state", "Test.dtime", "dtime"));

   state.doFile (true, "test.lua");
   
   int sum = luaadd (2, 2);
   Stdout.formatln ("sum is {}", sum);

    return 0;
}


Anyone interested in that, so I might add it to the bindings ?!
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clayasaurus



Joined: 21 May 2004
Posts: 857
PostPosted: Wed Jul 23, 2008 5:48 pm    Post subject: Reply with quote
If you think it would be useful to someone like yourself in the future, go ahead and add it. Nobody controls the bindings project, people just put useful code there. Plus, the D community is rather small, so I'd be surprised if anyone else answered you.

So sure, go ahead and add it.
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