Programming Languages: Concepts and Implementation

6.12 Thematic Takeaways

• Programming language concepts often have options, as with scoping (static or dynamic) and nonlocal reference binding (deep, shallow, or ad hoc).

• A closure—a function that remembers the lexical environment in which was created—is an essential element in the study of language concepts.

• The concept of binding is a universal and fundamental concept in programming languages. Languages have many different types of bindings; for example, scope refers to the binding of a reference to a declaration.

• Determining the scope in a programming language that uses manifest typing is challenging because manifest typing blurs the distinction between a variable declaration and a variable reference.

• Lexically scoped identifiers are useful ...