The libjit library implements just-in-time compilation functionality. Unlike other JITs, this one is designed to be independent of any particular virtual machine bytecode format or language. Currently, libjit is used as the JIT backend for the DotGNU Portable.NET project (in addition to its default CVM backend). However, the hope is that other Free Software projects can use this library rather than spending large amounts of time writing their own JIT from scratch.
ANTLR (ANother Tool for Language Recognition) is a language tool that provides a framework for constructing recognizers, compilers, and translators from grammatical descriptions containing C++, Java, or Sather actions. It is similar to the popular compiler generator YACC, however ANTLR is much more powerful and easy to use. ANTLR-produced parsers are not only highly efficient, but are both human-readable and human-debuggable (especially with the interactive ParseView debugging tool). ANTLR can generate parsers, lexers, and tree-parsers in either C++, Java, or Sather. ANTLR is currently written in Java.
Aubit 4GL compiler is a programming language based on (and compatible with) Informix-4GL. It provides an easy way to generate screen/form based programs, since statements for handling Windows, Forms, Menus, SQL, and similar are built-in. With support for SQL statements forming an intrinsic part of the language, it's especially suitable for developing database-oriented applications. Database connectivity is provided for PostgreSQL, MySQL, Informix, and others via ODBC. It supports both ncurses (console mode) and GTK+ (GUI mode) output.
Common Text Transformation Library is a library of C++ classes and functions to parse and modify STL strings. CTTL substring classes may be compared, inserted, replaced, and parsed with EBNF grammars. The compiled program implements a fast, thread-safe, re-entrant recursive descent parser.
SableCC is a parser generator that generates fully featured object-oriented frameworks for building compilers, interpreters, and other text parsers. In particular, generated frameworks include intuitive strictly-typed abstract syntax trees and tree walkers. SableCC also keeps a clean separation between machine-generated code and user-written code, which leads to a shorter development cycle.