Programming Language Concepts Exam Review

Why Learn Programming Language Concepts?

• Logic Based Languages are on the rise in popularity

• Learning how programming languages work helps when learning more languages in the future.

• Lambdas are being used in imperative languages more.

Imperative vs Declarative

• Imperative - Program tells the computer what to do and how to do it

  • Procedural Programming

  • Object-Oriented Programming

• Declarative - Program describes the characteristics of a solution

  • Functional Programming

  • Logic Programming

What does REPL Stand For?

• R: Read

• E: Evaluate

• P: Print

• L: Loop

Interpreter vs Compiler

• Interpreter: executes the program by reading and evaluating the code as it runs.

• Compiler: translates the entire program into machine code and doesn’t run it.

Lexical Analyzer

extracts tokens/words from text. Removes whitespace and comments

Syntax Analyzer(Compiler)

builds tokens into language structures (parse trees) based on the rules.

Semantic Analyzer (Compiler)

checks if the structures built follow language rules

What parser does ANTLR generate and what does it stand for?

ALL (Adaptive LL), LL stands for Left to right, left most derivation.

Scanner

tokenizes the characters and strips whitespace

Parser

determines if the tokens follow syntaxical rules, splits into an AST

Semantic Analyzer(Interpreter)

evaluates the expression

Grammer

Defines what programs in the language are allowed to look like.

AST

They represent the meaningful structure of the program, rather than the original text.

Printer

The printer takes the AST and turns it back into a readable textual representation.

Evaluator

The evaluator actually runs the program.

Environment

An Env stores information about variables.

Bindings

A binding is the association of a value or type with a variable.

Lexical scoping

the binding of a variable to a value (or type) is based on the code syntax structure

Dynamic scoping

a variable's values/type depends on the flow of control through a program, not any static structure of where it is defined.