Compiler Foundations

Pipeline

• Lexing -> Parsing -> Semantics -> IR -> Optimization -> Codegen
• Same idea, many valid designs

Tokens and lexemes

• Lexeme = exact text
• Token = kind + lexeme + position
• Positions enable helpful errors

Grammar

• Grammar defines structure
• Precedence and associativity come from the grammar

AST

• AST = meaning, not punctuation
• Drives later stages

Design choices

• Syntax, rules, errors, IR shape
• Pack tests behavior, not style