HANDBOOK / REFLEX REFERENCE MANUAL /

# Introduction

The scanner for a compiler generated with Gentle must be implemented as a function `yylex()`. This may be done manually or by using the scanner generator Lex. The tool Reflex provides a convenient way of constructing a scanner specification for Lex from information extracted from the Gentle specification, token description files, and other sources. In many cases no manual intervention is required, because existing descriptions can be reused.