Parse Tree

A concrete syntax tree or parse tree or parsing tree is an ordered, rooted tree that represents the syntactic structure of a string according to some formal grammar. Parse trees are usually constructed according to one of two competing relations, either in terms of the constituency relation of constituency grammars (= phrase structure grammars) or in terms of the dependency relation of dependency grammars. Parse trees are distinct from abstract syntax trees (also known simply as syntax trees), in that their structure and elements more concretely reflect the syntax of the input language. Parse trees may be generated for sentences in natural languages (see natural language processing), as well as during processing of computer languages, such as programming languages.