Chapter 13: Object-Based Abstractions

• Course Summary
• Abstractions of State
• Examples of Modifiable Objects
• Arithmetic Expressions Revisited
• Operator Precedence
• Using Precedence Rules
• Evaluating Expressions According to Precedence Rules
• Using an Expression Stack
• Expression Stack Trace
• Describing the Expression Evaluator
• Why the Element Below the Top Is Needed
• Another Scenario
• An Action Table for Unparenthesized Expressions
• Adding Parentheses to the Evaluation Method
• Stack Trace With Parentheses
• An Action Table With Parentheses
• Implementing the Evaluator
• RA-stack Operations in Scheme
• The evaluate Procedure
• The process Procedure
• Deciding When to Accept
• Deciding When to Reduce
• Deciding When to Shift
• Reducing the Stack
• The reduce! Procedure
• Utility Procedures
• Example Calls
• Data Abstraction Revisited
• Axioms for RA-Stacks
• Implementation Requirements
• Programming Paradigms
• Vectors (Section 11.6)
• Vector Example 1
• Vector Example 2
• Two-Vector Implementation of RA-Stacks
• Trade-Offs
• RA-Stack Creation
• RA-Stack Height and Emptiness
• Advertised and Unadvertised RA-Stack Operations
• RA-Stack Access
• The top-minus Procedure
• pop!
• push!
• Stack Overflow
• One Solution
• Another Solution
• An ADT for Nodes
• Implementing RA-Stacks Using Nodes
• RA-Stack Access
• Trade-Offs Again
• RA-Stack Mutation: Popping
• RA-Stack Mutation: Pushing
• Node Mutation
• pop!
• push!
• Back to the Expression Evaluator
• Yet Another RA-Stack Representation
• Cons Mutators
• Mutable Pairs in Racket
• Back to Yet Another RA-Stack Representation
• Data Abstraction
• LIFO vs. FIFO
• Operations for the Queue ADT
• A Suboptimal Queue Representation
• Shifting Queue Elements
• A Better Queue Representation
• Change Start Location, Don't Move Data
• End of the Vector
• Circular Queues
• A New Representation Invariant
• Calculating an Enqueued Item's Location
• Calculating the Start Location After a Dequeue
• Queue ADT Implementation
• A Linked-List Queue Representation