New Lua examples - Mark Gossage patch #1295168

git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk@7471 626c5289-ae23-0410-ae9c-e8d60b6d4f22

SWIG/Examples/lua/import.lua

@@ -0,0 +1,42 @@
+-- import
+-- the lua 5.0 loading mechanism is rather poor & relies upon the loadlib() fn
+-- the lua 5.1 loading mechanism is simplicity itself
+-- for now we need a bridge which will use the correct verion
+
+function import_5_0(module)
+	-- imports the file into the program
+	-- for a module 'example'
+	-- this must load 'example.dll' or 'example.so'
+	-- and look for the fn 'Example_Init()' (note the capitalisation)
+	if rawget(_G,module)~=nil then return end -- module appears to be loaded
+		
+	-- capitialising the first letter
+	local c=string.upper(string.sub(module,1,1))
+	local fnname=c..string.sub(module,2).."_Init"
+	
+	local suffix,lib
+	-- note: as there seems to be no way in lua to determine the platform
+	-- we will try loading all possible names
+	-- providing one works, we can load
+	for _,suffix in pairs{".dll",".so"} do
+		lib=loadlib(module..suffix,fnname)
+		if lib then -- found
+			break
+		end
+	end
+	assert(lib,"error loading module:"..module)
+	
+	lib() -- execute the function: initalising the lib
+	local m=rawget(_G,module)	-- gets the module object
+	assert(m~=nil,"no module table found")
+end
+
+function import_5_1(module)
+	require(module)
+end
+
+if string.sub(_VERSION,1,7)=='Lua 5.0' then
+	import=import_5_0
+else
+	import=import_5_1
+end