Lexical And Syntax Analysis

Compilation

involves translating high-level code into machine code using a compiler.

Pure interpretation

executes the original source code directly using an interpreter.

• Hybrid implementation

combines both methods. It translates high-level code into an intermediate representation, which is then interpreted.

Lexical analysis

also known as scanning, is the first phase of processing source code. It converts the raw source code into tokens

syntax analyzer

takes the generated tokens and verifies whether they follow the grammatical rules of the programming language.

lexical analyzer

is a pattern matcher that identifies tokens.

1. Simplicity

2. Efficiency

3. Portability

separate lexical analysis from syntax analysis to improve:

state diagram

represents a finite automaton used for token recognition.

Terminal Symbols

These are keywords, operators, or punctuation marks that cannot be broken down further.

Non Terminal Symbols

are like the branches of a tree—abstract structures built by combining terminals or other nonterminals.

Bottom-up parsing

• is a technique used in syntax analysis of programming languages, where the parser starts with the input and works backward to reconstruct the parse tree
  

• reconstruct a rightmost derivation in reverse.

LR parser

The most well-known bottom-up parsing algorithm

Rightmost Derivation

means we always expand (replace) the rightmost non-terminal first at each step.

Recursive-descent parsing

• is a top-down parsing method used in syntax analysis for programming languages

• It consists of a set of recursive rules, each corresponding to a nonterminal symbol in a grammar and produces a parse tree in top-down order.

Top-down parsers

Construct leftmost derivations and a parse tree in top-down order.

Syntax analysis

is a common part of language implementation, regardless of the implementation approach used. It is normally based on a formal syntax description of the language being implemented.

BNF (Backus-Naur Form)

The most common approach for describing syntax is a context-free grammar, also known as