The Bywater BASIC scripting language (bwBASIC) implements a large superset of the ANSI Standard for Minimal BASIC (X3.60-1978) and a significant subset of the ANSI Standard for Full BASIC (X3.113-1987) in C. It also offers shell programming facilities as an extension of BASIC. bwBASIC seeks to be as portable as possible.
Yabasic implements the most common and simple elements of the basic language. It comes with goto/gosub, with various loops, with user defined subroutines and libraries. Yabasic does monochrome line graphics and printing. Yabasic runs under Unix and Windows, it is small (around 200KB) and free.
ActivePerl is the industry-standard Perl distribution, available for Windows, Linux, Mac OS X, Solaris, AIX, and HP-UX. Complete and ready-to-install, the ActivePerl distribution includes core Perl, popular modules, the Perl Package Manager (PPM), and complete documentation. The Windows version provides additional features that have made ActivePerl the worldwide standard for Perl on Windows.
Berkely Logo (ucblogo) is an interpreter for the Logo programming language. Logo is a computer programming language designed for use by learners, including children. This dialect of Logo features random-access arrays, variable number of inputs to user-defined procedures, various error handling improvements, comments and continuation lines, first-class instruction and expression templates, and macros.
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.
Unlambda is an obfuscated functional programming language, a sort of frightening mixture of Intercal and Scheme. The distribution includes sample programs, Unlambda interpreters and documentation. This can be useful to learn functional language programming, or how to write interpreters.
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.