' Collapse some vertices on a polygon mesh.
dim obj, op
set obj = CreatePrim( "Grid", "MeshSurface" )
set op = ApplyTopoOp( "Collapse" , "grid.pnt[30-32,39-41,48-50]" )

// Example demonstrating how to get use ApplyTopoOp
// to create an operator and retrieve it from the return value.
NewScene( null, false );
// Get a pointer to the internal object database. 
var objdata = XSIUtils.DataRepository;
// Apply the Collapse operator in ImmediateMode to see what gets returned.
var obj = CreatePrim( "Grid", "MeshSurface" );
var ops = ApplyTopoOp( "Collapse" , obj + ".pnt[30-32,39-41,48-50]", null, siPersistentOperation);
// Because we only apply to a single object we only expect a 
// single item in the XSICollection.  But
// it is a good habit to use a "for" loop
// to go through all elements.
for (var i=0; i<ops.Count; i++) {
        logmessage( "New Operator: " + ops(i).Name +
                 ", Type: " + ops(i).Type + 
", ClassName: " + ClassName( ops(i) ) ) ;
}
// Output of above script:
//INFO : New Operator: Collapse Op ,Type: collapseop, ClassName: Operator

/*
        This example demonstrates what gets returned when you apply and freeze a TopoOp with the 
        ApplyTopoOp command in siImmediateOperation mode. 
        The command still returns a pointer to the operator, but, unlike the
        example above, it no longer exists in the scene, so you can't do anything with it.
        The tricky part is testing the returned object to see whether it is valid or not. Normally you can 
        test the class or type to determine its validity; however, these operators will tell you
        that they are Operator objects (Application.ClassName). The Type property
        returns an empty string, which you can also use to test for an operator's validity, but
        this example uses the DataRepository object instead.
        The DataRepository object is an internal database which keeps track of objects in Softimage. It
        holds the ID for each object in the system which you can retrieve with the GetIdentifier
        method.
        Note: This example is only provided to illustrate what to expect from an XSICollection 
        containing frozen operators. Normally, you would not be interested in the returned value
        of an apply-and-freeze-operator operation.
*/
NewScene( null, false );
// Get a pointer to the internal object database. 
var objdata = XSIUtils.DataRepository;
// Apply the Collapse operator in ImmediateMode to see what gets returned.
var obj = CreatePrim( "Grid", "MeshSurface" );
var ops = ApplyTopoOp( "Collapse" , obj + ".pnt[30-32,39-41,48-50]", null, siImmediateOperation );
for (var i=0; i<ops.Count; i++) {
        // Normally this returns 'collapseop'
        logmessage( "Type returns: '" + ops(i).Type + "'" );
        // Wrap the call to DataRepository.GetIdentifier in a try-catch block because it will
        // throw an error if the object is invalid (if it's valid, you would see a GUID)
        try {
                logmessage( objdata.GetIdentifier(ops(i), siObjectGUID) );
        } catch(e) {
                logmessage( "object is not valid" );
        }
}
// Output of above script:
//INFO : Type returns: ''
//INFO : object is not valid