lexer → parser → parsed tree
Compared with AST, parsed tree is too verbose, for example, parsed tree will contain left bracket and right bracket (show all things in production rules). But for AST, since it knows that there would be a node represents method body, it will skip showing left and right brackets
COMP 512: Advanced Compiler Construction
Cooper: Engineering a Compiler, 2e Lecture Slides
Lexer:
regex → non-deterministic finite automator → deterministic finite automator → minimal DFA → Scanner
RE to NFA
NFA to DFA
DFA to min DFA
visualize regular expression