Quex

Quex is a software tool that enables you to generate Mode Oriented Directly Coded Lexical Analyzers. It is designed for modern programming languages that aim to describe problems and solutions in the most succinct way possible. In turn, these languages include problem-specific mini-languages, such as C format strings. However, to efficiently handle such sub-languages, more than one lexical analyzer mode is needed.

Quex stands out because it provides convenient features to relate modes through inheritance, allow and disallow mode transitions, and to manage mode transition events. Moreover, it includes an 'indentation event' that facilitates the writing of lexical analyzers for indentation-based languages, such as Python. The software tool is designed to send tokens to the caller from within the machine. Even though the interface polls the sent tokens sequentially, Quex creates a complete C environment that includes the lexical analyzer engine, token classes and token queues.

With the assistance of the provided sample applications and documentation, it is possible to have a lexical analyzer running within a couple of hours. In essence, Quex enables the description of complicated lexical analysis, allowing for a more elegant approach. At the same time, simple applications can be written faster than with traditional lexical analyzer generators.