Basic Patterns:
- Mapping Grammars to Recursive-Descent Recognizers: convert formal language specification (grammar) into a parser.
- LL(1) Recursive-Descent Lexer: break up character streams into tokens.
- LL(1) Recursive-Descent Parser: make a parsing decision (choose parsing method) for the current (1) input symbol.
- LL(k) Recursive-Descent Parser: make a parsing decision (choose parsing method) for up to k next input symbols.
- "A language is just a set of valid sentences."
- "To parse, then, is to conjure up a two-dimensional parse tree from a flat token sequence."
Criticism:
This book could have been much better. It suffers from the following problems:
- Code examples:
- Incompleteness - critical functions are missing initially: code which uses match() starts on page 41, but match() implementation is shown on page 55 for the first time.
- Names of variables and functions are cryptic/not clear and do not follow one convention:
- variable names: T, p, c, x, k, i, r, Integer memoI, int memo, FOLLOW_INT_in_point37, _save,
- function names: LT(), LA(), isSpeculating(), alreadyParsedRule(), _list(), speculate_stat_alt1().
- Critical terms are used without introduction.
- Definitions seem chaotic/incomplete.
- Concepts are introduced in chaotic order.
- Some concepts seem to change meaning: current token becomes a lookahead token.
- There is a lot of alternative terminology that is used without introducing it properly: here are my notes on "lexer": Lexer: a type of recognizer; aka scanner, aka lexical analyzer, aka tokenizer: reads a stream of characters and yields a stream of tokens aka input symbols, aka vocabulary symbols.
