>>-type-------------------------------------------------------><
Returns the type of invocation for this stack frame. Possible values are:
- PROGRAM
The stack frame is the top level of a program.
- METHOD
The stack frame is a method invocation.
- ROUTINE
The stack frame is a routine invocation.
- INTERPRET
The stack frame is code created by an INTERPRET instruction.
- INTERNALCALL
The stack frame is a subroutine or function call to an internal label.
