This paper presents a tool called {\em Elex(Prolog)} to construct
tokenizers (lexical analysers, scanners, lexers) in Prolog.  It is
based on {\em Elex}, a multilingual scanner generator by Matthew
Phillips. The paper motivates the tool, and presents its functionality
and implementation. It also compares {\em Elex(Prolog)} to the only
alternative Prolog scanner generator that we are aware of: {\tt plex}.