Red is a next-generation programming language strongly inspired by Rebol, but with a broader field of usage thanks to its native-code compiler, from system programming to high-level scripting and cross-platform reactive GUI, while providing modern support for concurrency, all in a zero-install, zero-config, single 1MB file! During the work on the low-level parts of the new Red lexer, the need arised for intra-function factorization abilities to keep the lexer code as DRY as possible. Subroutines were introduced to solve that. They act as the GOSUB directive from Basic language. They are defined as a separate block of code inside a function's body and are called like regular functions (but without any arguments). ...