CS 143 Lecture02: Language Design and Instruction of Cool

Topics:

• Why are there new languages?
• Good-language criteria

History of ideas:

• Abstract(抽象)
• Types(类型)
• Reuse(复用)

History of Ideas

• Abstract

  Abstraction = Ignorance of some details

  Abstract is necessary to build a complex system, and the key is information hiding - only expose the essential

  Modes:

  • Via language
  • Via function / subroutine (LISP?)
  • Via module (ECMAScript)
  • Via class or abstract data types (Rust)

• Types

  • Originally, few(no) types
  • But types helps on building abstractions / compile time check.
  • Experiments with various forms of parameterization(a.k.a. generic types，也就是所谓“泛型”).
  • Best developed in functional programming(a.k.a. FP).

• Reuse

  It’s many common patterns while programming, but they’re hard to reuse.

  Tow popular approaches:

  • Type parameterization（泛型，List<int>、List<double>）
  • Classes and inheritance
  • （Where is Traits? 🤣