Outline:

1. Another recursive example
   • count-9s
   • count-val
2. Functions as arguments
   • count-predicate
3. Common higher-order functions
   • map
   • filter
   • fold
4. Wrap-up

What’s next

Upcoming events/assessments:

• Assignment 3 is due tonight
• Assignment 4 is released and due Wednesday night
• Quiz 1 will be this Friday and cover the following Quiz Learning Objectives:
  • Core:
    • PL 1: programming paradigms
    • FS 1: procedure calls
    • FS 2: cons cells
    • FS 3: recursion
    • FS 4: lambda
    • FS 5: higher-order functions
    • FS 8: reading Scheme
  • Advanced:
    • FS 9: car and cdr
    • FS 10: implementing higher-order functions
    • (maybe, but not guaranteed) FS 12: writing Scheme

What you should do now:

• Read the assigned readings (see below)
• Finish the exercises from last Friday
• Finish and submit Assignment 3
• Start Assignment 4 and bring questions to class Wednesday

Reading assignment (to be completed by the next class):

Currying and higher-order functions (from today):

• What is Currying - StackOverflow summary post - focus on the first one or two answers
• Higher Order Functions - just Sec. 1.1-1.8

More on higher-order functions (for next time):

• Using First-Class, Higher-Order, and Anonymous Procedures