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gracefully handling lua foulness..

nekoflux · 2004-03-04T11:06:50

hey all: In previous posts, many of you were quite helpful in getting lua built, and integrated into my current codebase. Everything works hunky dory, except for one thing: when my c++ code executes a lua script that contains lua code with syntax errors , or just does something the lua interpreter simply doesnt like, it crashes my c++ code. There must be some way to catch script errors from lua, and handle them gracefully. I''d imagine the lua interpreter, upon running a script with errors, must return with some sort of error message like "invalid script" or an error code...can I trap this in my code? Remember that since the core system is c++, simply handling exceptions within a lua script is not a suitable answer. thanks!! neko

Engines and Middleware Programming

Started by nekoflux March 01, 2004 10:00 PM

22 comments, last by nekoflux 20 years, 4 months ago

nekoflux

173

Author

March 02, 2004 05:48 PM

Borundin, the link you pasted has code that works great. Although proimarily what im after is being able to trap lua errors from within a non-static context, so that I can access class member variables. But I''ll keep this in mind as a last resort in the event that I cannot trap lua errors the way I want to.

Thanks again!

neko

nekoflux

Sneftel

1,788

March 02, 2004 09:48 PM

quote: Original post by nekoflux
now, in the above code, why isnt it firing the catch block? init.lua clearly contains code that is not of proper syntax...

thanks for your patience!

neko

Once again: LuaBind raises exceptions for _RUNTIME ERRORS_. Not syntax errors from loading. You''ll need to actually check the return value of lua_load; simply try/catching won''t work.

"Sneftel is correct, if rather vulgar." --Flarelocke

XXX_Andrew_XXX

340

March 03, 2004 01:09 AM

The following code is based on something Sneftel (? I think) wrote a while ago in this forum, and on the code from lua_dofile. It gets rid of the need to use stderr or stdout at all by converting errors in loading the script file into exceptions you can catch with C++. AFAIK all the luabind exceptions inherit from std::runtime_error.

If this doesn't fix your problem, make sure that it's not something to do with a luabind object's destructor being called after you call lua_Close.

void ScriptEngine::doFile(const std::string& filename){    if(luaL_loadfile(L_, filename.c_str()) != 0)    {        std::string errmsg = "Unknown loading error";        if(lua_isstring(L_,-1))        {            errmsg = lua_tostring( L_, -1 );        }        throw std::runtime_error(errmsg);    }    if(lua_pcall(L_, 0, LUA_MULTRET, 0) != 0)    {        std::string errmsg = "Unknown call message";        if(lua_isstring(L_,-1))        {            errmsg = lua_tostring( L_, -1 );        }        throw std::runtime_error(errmsg);    }}

[edit]fixed source tags[/edit]

[edited by - XXX_Andrew_XXX on March 3, 2004 2:11:23 AM]