returns the result of interpreting the object as an instance of ` variable descriptor ' . this implementation returns null ; returning a non-null result will terminate the switch . concode_field_sep FunctionModelPackage modelPackage concode_field_sep T caseFunctionDescriptor concode_elem_sep T doSwitch concode_elem_sep T doSwitch concode_elem_sep T doSwitch concode_elem_sep T caseEquationPart concode_elem_sep T caseVariableStep concode_elem_sep T caseEquationDescriptor concode_elem_sep T caseEquationSide concode_elem_sep T defaultCase
T function ( VariableDescriptor arg0 ) { return null ; }