Procedures (Hunk K)

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Hunk K starts here:
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Scheme procedures are "first class," meaning that they're objects in the language. They can be anonymous, meaning that you can have pointers to procedures that don't have printed names. They can be higher-order, meaning that procedures can operate on procedures.

• First Class Procedures: Procedures are objects in the language
• Higher-Order Procedures: Procedures can take procedures as arguments
• Anonymous Procedures and lambda: lambda creates procedure objects, which don't need names
• lambda and Lexical Scope
• Local Definitions: defines work locally, too
• Local Procedures and letrec: letrec is like let, but supports recursive definitions
• Multiple defines are Like a letrec: Understanding definitions and scope
• Variable Arity: Procedures can take a variable number of arguments
• apply