Re: how to recognize a multiple line comment ?

[Nicolas Peyrussie]

Hi,

I recognize and avoid html comments on multiple lines like this :
<INITIAL>"<!--"                  {yy_push_state(COMMENT);}
<COMMENT>"-->"              {yy_pop_state();}
<COMMENT>"\n"                {}
<COMMENT>.                      {}

So you have to do something like this; yy_push_state() adds COMMENT state on top of the stack, it is declared as exclusive (%x), and then you pop it at the end of the comment detection with yy_pop_state(), if you want to keep all I think you have to add yymore() on <COMMENT>"\n" {yymore();} and <COMMENT>. {yymore();}.

So something like this
<INITIAL>"/*"                  {yy_push_state(COMMENT);}
<COMMENT>"*/"            {
                                              /* add the action here*/
                                              yy_pop_state();
                                            }
<COMMENT>"\n"                {yymore();}
<COMMENT>.                      {yymore();}

Let me know if it works.
Regards,
Nicolas

ps: I think you have to add %option stack option for yy_push_state() and yy_pop_state() to work.

James Yu wrote:

Dear all,

I am trying to define a rule for recognizing a multiple line comment in C, but I have not yet sueccessed.
Thus, I am posting my lex segment to this email and hope you can point out some mistakes for me.

== flex code segment ==
slash        "/"
asterisk    "*"
comment  ({slash}{asterisk}+([^*]|[\n])*{asterisk}+{slash})
== flex code segment ==

Any help would be gratefully appreciated,
James

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