On Fri, Feb 12, 2021 at 01:20:07PM +0100, Florian Westphal wrote:
> Phil Sutter <phil@xxxxxx> wrote:
> > I didn't find a better way to conditionally parse two following args as
> > strings instead of just a single one. Basically I miss an explicit end
> > condition from which to call BEGIN(0).
>
> Yes, thats part of the problem.
>
> > > Seems we need allow "{" for "*" and then count the {} nests so
> > > we can pop off a scanner state stack once we make it back to the
> > > same } level that we had at the last state switch.
> >
> > What is the problem?
>
> Detect when we need to exit the current start condition.
>
> We may not even be able to do BEGIN(0) if we have multiple, nested
> start conditionals. flex supports start condition stacks, but that
> still leaves the exit/closure issue.
>
> Example:
>
> table chain {
> chain bla { /* should start to recognize rules, but
> we did not see 'rule' keyword */
> ip saddr { ... } /* can't exit rule start condition on } ... */
> ip daddr { ... }
> } /* should disable rule keywords again */
>
> chain dynamic { /* so 'dynamic' is a string here ... */
> }
> }
>
> I don't see a solution, perhaps add dummy bison rule(s)
> to explicitly signal closure of e.g. a rule context?
You can always push/pop the flexer state from bison code blocks, maybe
that's what you mean on "dummy bison rules".
Trigger the state from bison and make sure it ends.
Something like this:
diff --git a/src/parser_bison.y b/src/parser_bison.y
index 11e899ff..d8107181 100644
--- a/src/parser_bison.y
+++ b/src/parser_bison.y
@@ -2397,7 +2397,10 @@ chain_policy : ACCEPT { $$ = NF_ACCEPT; }
identifier : STRING
;
-string : STRING
+string : { yy_push_state(scanner, STRING); } __string { yy_pop_state(scanner); }
+ ;
+
+__string : STRING
| QUOTED_STRING
| ASTERISK_STRING
;
--
Bazsi
