Re: Extensions made by the Tilde debugger

[HyperHacker <hyperhacker@...>]

On Sat, Aug 27, 2011 at 17:03, Joshua Jensen <josh.jjensen@gmail.com> wrote:
> 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
>
>
>
>

These seem like quite useful extensions, although I'm not sure what
the difference is between the error hook and the handler set by
xpcall...

-- 
Sent from my toaster.