Generators Can Be Defined by other Procedures. Nameless Procedures Become Lexical Closures. Bindings Could Be Kept on a Record of Calls. Some Variables Are Declared To Be Special Forevermore. Special-Variable Bindings Are Actually Kept on a Stack.
Some Variable Instances Can Be Special while Others Are Lexical.
Both Lexical and Special Variables Can Be Free Variables. List Storage, Surgery, and Reclamation. Lists Can Be Represented by Boxes and Pointers. Boxes and Pointers Can Be Represented by Bytes. CONS Builds New Lists by Depositing Pointers in Free Boxes.