abstract syntax tree

In computer science, an abstract syntax tree (AST) is a finite, labeled, directed tree, where the internal nodes are labeled by operators, and the leaf nodes represent the operands of the operators. Thus, the leaves are NULL operators and only represent variables or constants. In computing, it is used in a  parser as an intermediate between a parse tree and a data structure, the latter of which is often used as a compiler or interpreter's internal representation of a computer program while it is being optimized and from which code generation is performed. The range of all possible such structures is described by the abstract syntax. An AST differs from a parse tree by omitting nodes and edges for syntax rules that do not affect the semantics of the program. The classic example of such an omission is grouping parentheses, since in an AST the grouping of operands is implicit in the tree structure. Creating an AST in a parser for a language described by a context free grammar, as nearly all programming languages are, is straightforward. Most rules in the grammar create a new node with the node's edges being the symbols in the rule. Rules that do not contribute to the AST, such as grouping rules, merely pass through the node for one of their symbols. Alternatively, a parser can create a full parse tree, and a post-pass over the parse tree can convert it to an AST by removing the nodes and edges not used in the abstract syntax.
See more at Wikipedia.org...

En informatique, un arbre syntaxique abstrait (abstact syntax tree ou AST en anglais) est un arbre avec des labels dont les nœuds internes sont marqués par des opérateurs et dont les nœuds fils ( feuilles ou nœuds externes ) représentent les opérandes de ces opérateurs. Autrement dit, chaque feuille a un opérateur de valence nulle (n'a pas d'opérande), des variables ou des constantes.
Pour la suite, voir Wikipédia.org…

Abstract Syntax Tree bezeichnet eine logische Baumstruktur, welche die inhaltlichen Zusammenhänge eines Dokumentes wiedergibt.
Mehr unter Wikipedia.org...

Drzewo AST (ang. abstract syntax tree) jest rodzajem drzewa, które przedstawia strukturę programu komputerowego. W drzewie tym węzłom będącym rodzicami przyporządkowane są operatory (działania), a liściom argumenty.na drzewie opisane jest wyrażenie: A(B(E,F),C,D(G(I),H(J,K,L))) A i H to operacje trójargumentowe B i D to operacje dwuargumentowe (binarne) G to operacja jednoargumentowa (unarna lub unitarna) E F C I J K L to argumenty
W celu uzyskania więcej informacji, zobacz w Wikipedia.οrg...

abstract syntax tree
(ast) a data structure representing something which has been parsed, often used as a compiler or interpreter's internal representation of a program while it is being optimised and from which code generation is performed. the range of all possible such structures is described by the abstract syntax.