In computer science, a compiler-compiler or compiler generator is a programming tool that creates a parser, interpreter, or compiler from some form of formal description of a programming language and machine.
The most common type of compiler-compiler is called a parser generator. It handles only syntactic analysis.
A formal description of a language is usually a grammar used as an input to a parser generator. It often resembles Backus–Naur form (BNF), extended Backus–Naur form (EBNF), or has its own syntax. Grammar files describe a syntax of a generated compiler's target programming language and actions that should be taken against its specific constructs.
Source code for a parser of the programming language is returned as the parser generator's output. This source code can then be compiled into a parser, which may be either standalone or embedded. The compiled parser then accepts the source code of the target programming language as an input and performs an action or outputs an abstract syntax tree (AST).
Parser generators do not handle the semantics of the AST, or the generation of machine code for the target machine.
A metacompiler is a software development tool used mainly in the construction of compilers, translators, and interpreters for other programming languages. However, both the generated compiler and the code it produced were inefficient in time and space. No production compilers are currently built in this way, but research continues.
The Production Quality Compiler-Compiler (PQCC) project at Carnegie Mellon University does not formalize semantics, but does have a semi-formal framework for machine description.
Compiler-compilers exist in many flavors, including bottom-up rewrite machine generators (see JBurg) used to tile syntax trees according to a rewrite grammar for code generation, and attribute grammar parser generators (e.g. ANTLR can be used for simultaneous type checking, constant propagation, and more during the parsing stage).