Re: [jflex-users] Lookahead expression must have match with at least length 1

[Steve R. <sa...@od...>]

Steve Rowe wrote:
> I *think* you can handle this situation by using three rules and a
> non-default lexical state:
> 
> %state NONROMAN
> ...
> {ROMANPAT} / [^a-z]  { return newTok("ROMAN"); }
> {ROMANPAT} / [a-z]   { yypushback(yylength()); yybegin(NONROMAN); }
> {ROMANPAT}           { return newTok("ROMAN"); }
> 
> <NONROMAN,YYINITIAL> {
>   ... // non-roman matching rules go here.
> }

Whoops, you only need two rules:

{ROMANPAT} / [a-z]   { yypushback(yylength()); yybegin(NONROMAN); }
{ROMANPAT}           { return newTok("ROMAN"); }

Steve