What is abstraction in the context of SICP?

Abstraction is the process of hiding implementation details and exposing only the essential features of a concept or system. It allows programmers to manage complexity by working with high-level ideas without worrying about low-level details.

Explain recursion and provide a simple example.

Recursion is a problem-solving technique where a function calls itself to solve smaller instances of the same problem.

Example (factorial function in Scheme): (define (factorial n) (if (= n 0) 1 (* n (factorial (- n 1)))))

What are higher-order functions in SICP?

Higher-order functions are functions that can take other functions as arguments or return functions as results. They allow for powerful abstractions and generalizations in programming.

Example: map, filter, reduce

What is a lambda expression in Scheme?

A lambda expression is a way to create anonymous functions in Scheme. It has the form:

(lambda (parameters) body)

Example: ((lambda (x) (* x x)) 5) ; Returns 25

Explain data abstraction in SICP.

Data abstraction is the principle of separating the way data is used from its concrete representation. It involves defining a set of procedures that operate on the data, hiding the details of how the data is stored or implemented.

What are streams in SICP and how do they differ from lists?

Streams are a sequence of data elements made available over time. Unlike lists, streams are evaluated lazily - elements are computed only when needed. This allows for working with infinite sequences and can improve efficiency for large data sets.

What is metalinguistic abstraction in SICP?

Metalinguistic abstraction involves creating new languages or modifying existing ones to better suit specific problem domains. It's about designing languages that can express solutions more naturally for certain types of problems.

Describe the environment model of evaluation in SICP.

The environment model is a way to understand how variables are looked up and how procedures are evaluated. An environment is a sequence of frames, each containing variable bindings. When a variable is referenced, it's looked up in the current environment, moving to enclosing environments if not found.