Deep and Shallow Binding: the Assignment Operation

Programming languages which use dynamic identification for free variables (i.e., nonlocal referencest are generally implemented with a deep or shallow binding variable access strategy. In this paper, variable access through the binding environment is assumed to be desirable. Given this assumption, it is demonstrated that the act of assigning values to variables may yield unexpected results for some of the binding strategies when functional arguments and results are used. A number of variations of deep and shallow binding strategies are examined along with the modifications necessary to implement the assignment operation in the expected manner Deep binding Shallow binding Dynamic binding Access environments Functional arguments Binding environments Activation environments