Pascal-P4 for Free Pascal and Delphi is a port of a Pascal compiler written at ETH Zurich in 1976. The source code of the compiler is documented in the book "Pascal Implementation" by Steven Pemberton and Martin Daniels. The purpose of this project is to make Pascal-P compilable by Free Pascal and Delphi while keeping the changes to a minimum and preserving the line numbering as much as possible.
Racket (formerly PLT Scheme) is a programming language suitable for implementation tasks ranging from scripting to application development, including GUIs, Web services, etc. It includes the DrRacket programming environment, a virtual machine with a just-in-time compiler, tools for creating stand-alone executables, the Racket Web server, extensive libraries, documentation for both beginners and experts, and more. It supports the creation of new programming languages through a rich, expressive syntax system. Example languages include Typed Racket, ACL2, FrTime, and Lazy Racket.
CIL is a frontend for the C programming language which facilitates program analysis and transformation. CIL will parse and typecheck a program, and compile it into a simplified subset of C. For example, in CIL, all looping constructs are given a single form and expressions have no side effects. This reduces the number of cases which must be considered when manipulating a C program. CIL has been used for a variety of projects, including CCured, a tool which makes C programs memory safe. It supports ANSI C, as well as most of the extensions of the GNU C and Microsoft C compilers. A Perl script acts as a drop-in replacement for either gcc or Microsoft's cl, and allows merging of the source files in your project. Other features include support for control-flow and points-to analyses.
Mercury is a new logic/functional programming language, which combines the clarity and expressiveness of declarative programming with advanced static analysis and error detection features. Its highly optimized execution algorithm delivers efficiency far in excess of existing logic programming systems, and close to conventional programming systems. Mercury addresses the problems of large-scale program development, allowing modularity, separate compilation, and numerous optimization/time trade-offs.
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.