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Objects and Classes

• Object:
  • Declared variable of a record-structure block.
  • Centerpiece of object-oriented languages.
  • Record field = object methods.
• Embedding of classes:
  • class EXTENDED-STACK =
    begin
       var M: PERSONAL-STACK,
       var N: newint
    in record
       ...
       proc PUSH-EXTENDED(X: intexp) =
          call M.PUSH(X)
       ...
    end end

Forwarding of method invocations becomes tiresome!