Formal languages

A two-level grammar is a formal grammar that is used to generate another formal grammar , such as one with an infinite rule set .

In computer science, an abstract syntax tree (AST), or just syntax tree, is a tree representation of the abstract syntactic structure of source code written in a programming language.

A context-sensitive grammar (CSG) is a formal grammar in which the left-hand sides and right-hand sides of any production rules may be surrounded by a context of terminal and nonterminal symbols.

SCIgen is a computer program that uses context-free grammar to randomly generate nonsense in the form of computer science research papers.

In computer science, Backus–Naur Form or Backus Normal Form (BNF) is one of the two main notation techniques for context-free grammars, often used to describe the syntax of languages used in computing, such as computer programming languages, document formats, instruction sets and communication protocols; the other main technique for writing context-free grammars is the van Wijngaarden form.

In formal language theory, a grammar (when the context is not given, often called a formal grammar for clarity) is a set of production rules for strings in a formal language.

In mathematical logic and theoretical computer science, an abstract rewriting system (also (abstract) reduction system or abstract rewrite system; abbreviation ARS) is a formalism that captures the quintessential notion and properties of rewriting systems.

In computer programming, a string is traditionally a sequence of characters, either as a literal constant or as some kind of variable.

In theoretical computer science and formal language theory, a regular expression (sometimes called a rational expression) is a sequence of characters that define a search pattern, mainly for use in pattern matching with strings, or string matching, i.

In a formal grammar, an erasing rule is a rule which maps a string of symbols to the empty string (ε).

Introduction to Automata Theory, Languages, and Computation is an influential computer science textbook by John Hopcroft and Jeffrey Ullman on formal languages and the theory of computation.

A Turing machine is an abstract machine that manipulates symbols on a strip of tape according to a table of rules; to be more exact, it is a mathematical model of computation that defines such a device.

A tell-tale or telltale is an indicator, signal, or sign that conveys the status of a situation, mechanism, or system.

A production or production rule in computer science is a rewrite rule specifying a symbol substitution that can be recursively performed to generate new symbol sequences.

A metacharacter is a character that has a special meaning (instead of a literal meaning) to a computer program, such as a shell interpreter or a regular expression engine.

CIAA, the International Conference on Implementation and Application of Automata is an annual academic conference in the field of computer science.

In mathematics, an antimatroid is a formal system that describes processes in which a set is built up by including elements one at a time, and in which an element, once available for inclusion, remains available until it is included.

DCFS, the International Workshop on Descriptional Complexity of Formal Systems is an annual academic conference in the field of computer science.

According to Rudolf Carnap, in logic, an interpretation is a descriptive interpretation (also called a factual interpretation) if at least one of the undefined symbols of its formal system becomes, in the interpretation, a descriptive sign (i.e., the name of single objects, or observable properties).

DLT, the International Conference on Developments in Language Theory is an academic conference in the field of computer scienceheld annually under the auspices of the European Association for Theoretical Computer Science.