Parsetræet

Parsetræet, often translated as parse tree or abstract syntax tree (AST) in English, is a fundamental concept in computer science, particularly in the field of compilers and interpreters. It represents the syntactic structure of source code according to a specific grammar. When a program's source code is processed, a parser analyzes it to determine if it conforms to the language's rules. The output of this process is typically a tree-like data structure where internal nodes represent operations or constructs, and leaf nodes represent operands or terminals of the grammar.

The structure of a parsetræet directly reflects the hierarchical organization of the code. For instance, in an expression like "a + b * c", a parsetræet would show the addition operation as a higher-level node, with 'a' as one child and the multiplication of 'b' and 'c' as the other. The multiplication node would, in turn, have 'b' and 'c' as its children. This hierarchical representation is crucial for understanding the program's logic and for subsequent stages of compilation, such as semantic analysis, optimization, and code generation.

Different types of parsetræer exist, including concrete syntax trees and abstract syntax trees. A concrete syntax tree, also known as a derivation tree, closely mirrors the actual grammar rules used in parsing, including all tokens and non-terminal symbols. An abstract syntax tree, however, omits non-essential information such as punctuation and grouping symbols, focusing solely on the essential structural and semantic components of the code. ASTs are generally preferred for further processing due to their conciseness and direct representation of the code's meaning.