parsergeneratorer

Parsergeneratorer are software tools that automatically produce source code for a parser based on a formal grammar specification. The grammar is typically written in an extended Backus–Naur form that describes the syntax of a language or data format. The parsergeneratorer then analyze the grammar to construct parsing tables or tree-walking code, and emit code in a target programming language such as C, Java, or Python.

The concept dates back to the 1970s with the creation of YACC (Yet Another Compiler Compiler) for Unix. Subsequent tools such as CUP for Java, Bison (the GNU replacement for YACC), and JavaCC evolved the idea by adding features like better support for modern programming languages, integrated scanner generators, and more advanced conflict resolution strategies. In the late 1990s and early 2000s, ANTLR (Another Tool for Language Recognition) introduced a powerful parser-generating framework that supports both LL(*) and LALR(1) parsing, a rich set of grammar annotations, and the ability to generate parsers in multiple target languages.

Parsergeneratorer typically produce two main components from a grammar: a lexical analyser (scanner) that tokenises raw input and a syntactic analyser (parser) that builds a parse tree or abstract syntax tree (AST). Many of the latest generators also allow the embedding of semantic actions directly in the grammar rules, making it easy to attach code that runs when a rule is matched.

These tools are widely used in compiler construction, language interpreters, static analysis, and data conversion utilities. They reduce manual coding effort, improve reliability, and provide a single source of truth for the language specification. However, they can generate large amounts of code that may be difficult to understand and debug, and sometimes require custom modifications to handle non-standard parsing scenarios.