YYAST is a library which completes Lex and Yacc by adding an Abstract Syntax Tree (AST). It is designed so that you write as little as code as possible in the Lex and Yacc grammar files, so that it doesn't distract from the grammar of the language, and is intended to make it easier to use high level programming languages for compilers.
HGL is a compiler/interpreter suite for developing images. It features its own simple but powerful language, Lua integration, output in various formats as well as runtime input handled by plugins, and easy integration into various environments like Web servers or graphical applications. The input is taken from a source file, which has to be compiled for quick and frequent access by the interpreter. An interpreter then runs the compiled files, takes input from custom plugins (if neccessary), and outputs its result via custom plugins.
cproto generates function prototypes for functions defined in the specified C source files to the standard output. The function definitions may be in K&R or ANSI C style, or in the lint library form. cproto can also convert function definitions in the specified files from the K&R style to the ANSI C style.