1 files changed, 29 insertions, 0 deletions

diff --git a/src/compat.h b/src/compat.h
new file mode 100644
index 0000000..a5801c4
--- /dev/null
+++ b/src/compat.h
@@ -0,0 +1,29 @@
+#if !defined( __COMPAT_H__)
+#define __COMPAT_H__ 1
+
+// code is now using Lua 5.2 API
+// add Lua 5.2 API when building for Lua 5.1
+#if LUA_VERSION_NUM == 501
+#define lua_absindex( L, idx) (((idx) >= 0 || (idx) <= LUA_REGISTRYINDEX) ? (idx) : lua_gettop(L) + (idx) +1)
+#define lua_pushglobaltable(L) lua_pushvalue( L, LUA_GLOBALSINDEX)
+#define lua_setuservalue lua_setfenv
+#define lua_getuservalue lua_getfenv
+#define lua_rawlen lua_objlen
+#define luaG_registerlibfuncs( L, _funcs) luaL_register( L, NULL, _funcs)
+#define LUA_OK 0
+#define LUA_ERRGCMM 666 // doesn't exist in Lua 5.1, we don't care about the actual value
+void luaL_requiref (lua_State* L, const char* modname, lua_CFunction openf, int glb); // implementation copied from Lua 5.2 sources
+#endif // LUA_VERSION_NUM == 501
+
+// wrap Lua 5.2 calls under Lua 5.1 API when it is simpler that way
+#if LUA_VERSION_NUM == 502
+#ifndef lua_equal // already defined when compatibility is active in luaconf.h
+#define lua_equal( L, a, b) lua_compare( L, a, b, LUA_OPEQ)
+#endif // lua_equal
+#ifndef lua_lessthan // already defined when compatibility is active in luaconf.h
+#define lua_lessthan( L, a, b) lua_compare( L, a, b, LUA_OPLT)
+#endif // lua_lessthan
+#define luaG_registerlibfuncs( L, _funcs) luaL_setfuncs( L, _funcs, 0)
+#endif // LUA_VERSION_NUM == 502
+
+#endif // __COMPAT_H__