Extensions made by the Tilde debugger

[Joshua Jensen <josh.jjensen@...>]

Hi.

The very cool Tilde debugger makes the following modifications to the 
Lua core in order to make the debugger more usable:

* A hook to catch errors, allowing the debugger to break at the point of 
error in the code and allow the user to investigate further.
* The ability to expand varargs.

The patch is below.  Does Lua 5.2 expose facilities for this now?

Thanks.

Josh

------------

--- lua/v5.1.3/src/ldebug.c    2008/05/13 12:41:06
+++ lua/v5.1.3/src/ldebug.c    2008/11/18 11:09:05
@@ -146,6 +146,24 @@
   return name;
 }

+LUA_API int lua_getvararg (lua_State *L, const lua_Debug *ar, int n) {
+  CallInfo *ci = L->base_ci + ar->i_ci;
+  if(isLfunction(ci->func))
+  {
+    Closure *cl = (Closure *) clvalue(ci->func);
+    StkId firstVarArg = ci->func + cl->l.p->numparams + 1;
+    int numVarArg = (int) (ci->base - firstVarArg);
+    if(n <= numVarArg)
+    {
+      lua_lock(L);
+      luaA_pushobject(L, firstVarArg + n - 1);
+      lua_unlock(L);
+      return n;
+    }
+  }
+  return 0;
+}
+

 static void funcinfo (lua_Debug *ar, Closure *cl) {
   if (cl->c.isC) {
@@ -608,6 +626,8 @@
     incr_top(L);
     luaD_call(L, L->top - 2, 1);  /* call it */
   }
+  if (L->hookmask & LUA_MASKERROR)
+    luaD_callhook(L, LUA_HOOKERROR, -1);
   luaD_throw(L, LUA_ERRRUN);
 }

--- lua/v5.1.3/src/lua.h    2008/05/13 12:41:06
+++ lua/v5.1.3/src/lua.h    2008/11/18 11:09:05
@@ -313,6 +313,7 @@
 #define LUA_HOOKLINE    2
 #define LUA_HOOKCOUNT    3
 #define LUA_HOOKTAILRET 4
+#define LUA_HOOKERROR    5


 /*
@@ -322,6 +323,7 @@
 #define LUA_MASKRET    (1 << LUA_HOOKRET)
 #define LUA_MASKLINE    (1 << LUA_HOOKLINE)
 #define LUA_MASKCOUNT    (1 << LUA_HOOKCOUNT)
+#define LUA_MASKERROR    (1 << LUA_HOOKERROR)

 typedef struct lua_Debug lua_Debug;  /* activation record */

@@ -336,6 +338,7 @@
 LUA_API const char *lua_setlocal (lua_State *L, const lua_Debug *ar, 
int n);
 LUA_API const char *lua_getupvalue (lua_State *L, int funcindex, int n);
 LUA_API const char *lua_setupvalue (lua_State *L, int funcindex, int n);
+LUA_API int lua_getvararg (lua_State *L, const lua_Debug *ar, int n);

 LUA_API int lua_sethook (lua_State *L, lua_Hook func, int mask, int 
count);
 LUA_API lua_Hook lua_gethook (lua_State *L);
--- lua/v5.1.3/src/luaconf.h    2008/05/13 12:41:06
+++ lua/v5.1.3/src/luaconf.h    2008/11/18 11:09:05
@@ -161,7 +161,11 @@

 #else

+#if defined(__cplusplus)
+#define LUA_API        extern "C"
+#else
 #define LUA_API        extern
+#endif

 #endif