Search results
Results from the WOW.Com Content Network
Applying the rules recursively to a source string of symbols will usually terminate in a final output string consisting only of terminal symbols. Consider a grammar defined by two rules. In this grammar, the symbol Б is a terminal symbol and Ψ is both a non-terminal symbol and the start symbol. The production rules for creating strings are as ...
Σ is a finite set of terminals, disjoint from V, which make up the actual content of the sentence. The set of terminals is the alphabet of the language defined by the grammar G. R is a finite relation in (), where the asterisk represents the Kleene star operation.
In computer programming, the interpreter pattern is a design pattern that specifies how to evaluate sentences in a language. The basic idea is to have a class for each symbol ( terminal or nonterminal ) in a specialized computer language .
Its applications are found in theoretical computer science, theoretical linguistics, formal semantics, mathematical logic, and other areas. A formal grammar is a set of rules for rewriting strings, along with a "start symbol" from which rewriting starts. Therefore, a grammar is usually thought of as a language generator.
Let A be a non-terminal. FIRST(A) is (defined to be) the set of terminals that can appear in the first position of any string derived from A. FOLLOW(A) is the union over: [12] FIRST(B) where B is any non-terminal that immediately follows A in the right-hand side of a production rule. FOLLOW(B) where B is any head of a rule of the form B → wA.
A → w, where A is a non-terminal in N and w is in a (possibly empty) string of terminals Σ * A → wB, where A and B are in N and w is in Σ *. Some authors call this type of grammar a right-regular grammar (or right-linear grammar) [1] and the type above a strictly right-regular grammar (or strictly right-linear grammar). [2]
Context-free languages are a category of languages (sometimes termed Chomsky Type 2) which can be matched by a sequence of replacement rules, each of which essentially maps each non-terminal element to a sequence of terminal elements and/or other nonterminal elements.
In computer science, the syntax of a computer language is the rules that define the combinations of symbols that are considered to be correctly structured statements or expressions in that language. This applies both to programming languages , where the document represents source code , and to markup languages , where the document represents data.