This is a list of formal language and literal string topics, by Wikipedia page. Formal languages Abstract syntax tree Backus-Naur form Categorial grammar Chomsky hierarchy Concatenation Context-free grammar Context-sensitive grammar Context-sensitive language Decidable language ECLR-attributed grammar Finite language Formal grammar Formal language Formal system Generalized star height problem Kleene algebra Kleene star L-attributed grammar LR-attributed grammar Myhill-Nerode theorem Parsing expression grammar Prefix grammar Pumping lemma Recursively enumerable language Regular expression Regular grammar Regular language S-attributed grammar Star height Star height problem Syntactic monoid Syntax (logic) Tree-adjoining grammar Literal strings Anagram Case sensitivity Infinite monkey theorem Lexical analysis Lexeme Lexicography Lexicon Lipogram The Library of Babel Palindrome Pangram Sequence alignment Classical cryptography Atbash cipher Autokey cipher Bazeries cylinder Bible code Bifid cipher Caesar cipher Cardan grille Enigma machine Frequency analysis Index of coincidence Playfair cipher Polyalphabetic substitution Polybius square ROT13, ROT47 Scytale Steganography Substitution cipher Tabula recta Transposition cipher Vigenère cipher Formal languages