The Gobo Eiffel Tools Library is an Eiffel class library useful for writing tools that expect Eiffel source code as input. It provides Ace and Xace parsers, an Eiffel parser which generates Abstract Syntax Trees, and numerous processors traversing these ASTs to perform code analysis using various compilation techniques. Tools that can take advantage of this library are Eiffel compilers and interpreters, lint-like tools, pretty-printers or flat-short form generators, test tools, ctags-like tools, Eiffel reflection generators, Eiffel preprocessing tools, and more.