lcc is a retargetable compiler for ISO Standard C. It generates code for the ALPHA, SPARC, MIPS R3000, and Intel x86 and its successors. Despite the fact that any Linux system will already have gcc, there are reasons for installing lcc as well. lcc is small, compiles more quickly than gcc, and helps prevent some porting bugs. It also gives more useful error messages in some circumstances. This means that it is sensible to use lcc during development, and gcc for the final binary where you want the better optimization.
Gwydion Dylan is a portable, optimizing Dylan compiler written in Dylan. It was originally written by the Gwydion Group at CMU and is now maintained by volunteers. Eventually, Gwydion Dylan is meant to become a top-notch tool for building complicated applications. Dylan is a dynamic, object-oriented language with four design goals: high performance, rapid prototyping, ease of use, and seamless support for using libraries written in C. Ports of Gwydion Dylan are available for many platforms.
SmartEiffel is the GNU Eiffel Compiler. It is intended to be a complete, though small and very fast, Eiffel compiler. The current distribution includes an Eiffel to C compiler, documentation tools, a pretty printer, and various other tools including an Eiffel debugger. It also includes a large library of classes distributed under the terms of the MIT/X Consortium License. Eiffel is an advanced object-oriented programming language that emphasizes the design and construction of high-quality and reusable software.
The Free Pascal Compiler is a Turbo Pascal 7.0 and Delphi-compatible 32/64 bit Pascal Compiler. It comes with a fully TP 7.0-compatible run-time library. Some extensions have been added to the language, like function overloading. Shared libraries can be linked. Basic Delphi support is implemented with classes, exceptions, RTTI, and ansistrings. A Free Component Library (FCL) is available with the base classes. Bindings for X11, ncurses, GTK, OpenGL, zlib, mysql, interbase and postgres are available.
The GNU Compiler Collection contains frontends for C, C++, Objective-C, Fortran, Java, and Ada as well as libraries for these languages. It is a full-featured ANSI C compiler with support for K&R C as well. GCC provides many levels of source code error checking traditionally provided by other tools (such as lint), produces debugging information, and can perform many different optimizations to the resulting object code.
Octave is a high-level language, primarily intended for numerical computations. It provides a convenient command line interface for solving linear and nonlinear problems numerically, and for performing other numerical experiments. It may also be used as a batch-oriented language.