Re: [jflex-users] mau be a bug with the negation operator

[Gerwin K. <ge...@do...>]

Hi Pascal,

I haven’t really gotten to the bottom of it yet, but it is some interaction between the presence of a negated character class and the negation operator.

If you need a work-around, changing the spec to the equivalent

EXP = [\u{0}-`b-\u{10FFFF}] [^]* [\u{0}-`b-\u{10FFFF}]

should make it work as expected (you can tell when jflex warns that the second action can never be matched). 

Cheers,
Gerwin 

> On 22 Oct 2019, at 02:50, Pascal HENNEQUIN <pas...@te...> wrote:
> 
> hello,
>   I found an issue with the negation operator "!"
>   With the following specification, string "baba" is not matched
>   by either EXP ou !EXP .
> 
> Pascal Hennequin
> 
> 
> -------------------------------
> %%
> %standalone
> %{
> void ECHO(String cat) { System.out.print("["+cat+":"+yytext()+"]"); }
> %}
> 
> EXP = ( [^a] [^]* [^a] )
> ALL = {EXP} | ! {EXP}  
> 
> %%
> {ALL}  { ECHO("1"); }
> baba   { ECHO("2"); }
> ---------------------------------
> 
> 
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