The experience with transformational implementation of compilers using TXL, a transformational programming language, motivated the creation of a tool which improves the
programming activity. This was our purpose when proposing LET, a transformation specification language ("Linguagem para Especificar Transformações"), and
its compiler prototype which generates code for TXL machine. Initially, we do an overview of the subject and the TXL language. Subsequently, its main features as a transformation
specification language.