public PinnedVariableExpression Derive(
string format
)
var expression = new PinnedVariableExpression("TIMER1", "(Timer *)0x1234");
var controlRegister = expression.Derive("({0})->CR");
Debug.Assert(controlRegister.AsEntered == "(TIMER1)->CR");
Debug.Assert(controlRegister.Preprocessed == "((Timer *)0x1234)->CR");