Squirrel

Hello,

I've got a class Vector3 bound to squirrel, and it has a function Vector3::add(Vector3* vector).
Now I also have another class, lets say Player, bound to squirrel.

The odd thing is, when I try to do this in a squirrel script:

local v = Vector3(1.0, 2.0, 3.0);
local p = Player();

local v2 = v + p;

SqPlus seems to simply cast the Player* into a Vector3* when the function Vector3::add is called?
Should there not be a runtime exception from SqPlus?

Is this normal SqPlus behavior or am I doing something wrong?

Thanks in advance.

Ok, I seem to have nailed it down to line 520 in sqplus.h:

// Get an instance of type T from the stack at idx (for function calls).
template<typename T,bool ExceptionOnError>
T * GetInstance(HSQUIRRELVM v,SQInteger idx) {
  SQUserPointer up=0;
  sq_getinstanceup(v,idx,&up,ClassType<T>::type());        if (ExceptionOnError) { // This code block should be compiled out when ExceptionOnError is false. In any case, the compiler should not generate a test condition (include or exclude the enclosed code block).
    if (!up) throw SquirrelError(_T("GetInstance: Invalid argument type"));
  } // if
  return (T *)up;
} // GetInstance


In my case, the sq_getinstanceup returns an error, and this error is not checked. I'm not sure if this is intended?

Ok changing that to:

template<typename T,bool ExceptionOnError>
T * GetInstance(HSQUIRRELVM v,SQInteger idx) {
  SQUserPointer up=0;
  bool failed = SQ_FAILED(sq_getinstanceup(v,idx,&up,ClassType<T>::type()));

  if (ExceptionOnError) { // This code block should be compiled out when ExceptionOnError is false. In any case, the compiler should not generate a test condition (include or exclude the enclosed code block).
    if (!up || failed) throw SquirrelError(_T("GetInstance: Invalid argument type"));
  } // if
  return (T *)up;
} // GetInstance

Seems to fix my problems.
Could any of the SqPlus devs comment on this?

Hi, Thank you for your contribution.
I've made a branch for this change and added a test code.
Please check SVN at https://sqplus.svn.sourceforge.net/svnroot/sqplus/branches/neimod-typesafe-r152

I will merge it into SVN trunk if it's OK with you.

Regards,
--
K. Kawachi

Sure, no problem.

Happy to contribute :)

Hi Katsuaki,

I've found a bug with my replacement code!

The SqPlus Match() for example requires proper return values from the GetInstance function, and in my replacement code, if the exceptionOnError flag is set to false, it will still return a pointer to the UP, even if it was invalid. This is not right, it should return NULL in this case.

Here my new version of the code:

template<typename T,bool ExceptionOnError>
T * GetInstance(HSQUIRRELVM v,SQInteger idx) {
  SQUserPointer up=0;
  const bool failed = SQ_FAILED(sq_getinstanceup(v,idx,&up,ClassType<T>::type()));

  if (failed)
      up = 0;

  if (ExceptionOnError) { // This code block should be compiled out when ExceptionOnError is false. In any case, the compiler should not generate a test condition (include or exclude the enclosed code block).
    if (!up) throw SquirrelError(_T("GetInstance: Invalid argument type"));
  } // if
  return (T *)up;
} // GetInstance

Hi,

The SVN branch is updated.  Thank you.

I'd completely forgotten what I did around "GetInstance" two years ago.
 http://squirrel-lang.org/forums/thread/962.aspx
:-D
--
K. Kawachi

The svn branch merged into trunk.
--
K. Kawachi

Hi Katsuaki,

SqPlus is now only typesafe when compiling in Debug mode, for Release mode it will sometimes allow invalid type conversions.
Please see http://squirrel-lang.org/forums/thread/2486.aspx for a solution.

Thank you.