Squirrel

Hi All,

I am a beginner to Squirrel and SqPlus, in here I would like to share my experiences when I am embedding Squirrel into my 3d graphics framework.

This example shows how to access a C++ object which is created and returned from script; and shows the life-cycle of the object. It may not be the official way; and it may contains error. Please help to point them out if any.

Thanks

#include <sqplus.h>

class Counter
{
public:
    Counter()
        : mCnt( 0 )
    {
        printf("Counter::cstor\n");
    }

    ~Counter()
    {
        printf("Counter::dstor\n");

    }

    void Inc()
    {
        mCnt++;
    }

    int GetCount() const
    {
        return mCnt;
    }

    static void DoBinding()
    {
        SQClassDef<Counter>("Counter")
            .func( &Counter::Inc, "Inc" )
            .var( &Counter::mCnt, "Cnt", VAR_ACCESS_READ_ONLY )
            ;
    }

private:
    int mCnt;
};


static void MyPrintFunc( HSQUIRRELVM v, const SQChar * s, ... )
{
    static SQChar temp[2048];

    va_list vl;

    va_start( vl, s );
    
    scvsprintf( temp, s, vl );
    
    SCPUTS( temp );
    
    va_end( vl );

}

static void RunTestScript( const SQChar * script )
{
    SquirrelObject buf = SquirrelVM::CompileBuffer( script );

    printf( "----- RunTestScript -----\n" );

    try
    {
        SquirrelVM::RunScript( buf );

        SquirrelFunction<squirrelobject> callFunc(_T("GetCounter"));
        SquirrelObject ret = callFunc();

        if ( !ret.IsNull() )
        {
            // assume the type must be Counter
            Counter * counter = (Counter *)ret.GetInstanceUP( ClassType<Counter>::type() );

            if ( counter )
                printf( "C++: counter.Cnt = %d\n", counter->GetCount() );
        }
    }
    catch ( SquirrelError & e )
    {
        scprintf(
              _T( "Error: %s\n" )
            , e.desc
            );
    }
    
    printf( "\n" );
}

int main()
{
    const SQChar * script1 = _T(
        "function GetCounter()\n"
        "{\n"
        "    local counter1 = Counter();\n"
        "    counter1.Inc();\n"
        "    print( format( \"Squirrel: counter1.Cnt = %d\", counter1.Cnt ) );\n"
        "    return counter1;\n"
        "}\n"
        );

    const SQChar * script2 = _T(
        "function GetCounter()\n"
        "{\n"
        "    local counter2 = Counter();\n"
        "    counter2.Inc();\n"
        "    counter2.Inc();\n"
        "    print( format( \"Squirrel: counter2.Cnt = %d\", counter2.Cnt ) );\n"
        "    return counter2;\n"
        "}\n"
        );

    const SQChar * script3 = _T(
        "function GetCounter()\n"
        "{\n"
        "    local counter3 = Counter();\n"
        "    counter3.Inc();\n"
        "    counter3.Inc();\n"
        "    counter3.Inc();\n"
        "    print( format( \"Squirrel: counter3.Cnt = %d\", counter3.Cnt ) );\n"
        "    return counter3;\n"
        "}\n"
        );

    printf("VM Init\n");

    SquirrelVM::Init();

    sq_setprintfunc( SquirrelVM::GetVMPtr(), MyPrintFunc );

    Counter::DoBinding();

    // run script1
    RunTestScript( script1 );

    // run script2
    RunTestScript( script2 );

    // run script3
    RunTestScript( script3 );

    printf("VM Shutdown\n");

    SquirrelVM::Shutdown();

    return 0;
}

VM Init
----- RunTestScript -----
Counter::cstor
Squirrel: counter1.Cnt = 1
C++: counter.Cnt = 1

----- RunTestScript -----
Counter::dstor
Counter::cstor
Squirrel: counter2.Cnt = 2
C++: counter.Cnt = 2

----- RunTestScript -----
Counter::dstor
Counter::cstor
Squirrel: counter3.Cnt = 3
C++: counter.Cnt = 3

VM Shutdown
Counter::dstor