On Mon, 24 Jun 2002, Kin-Man Chung wrote:
> > > Use of scripting varibles in nested tag never work before, so obviously
> > > no body uses it much. I think the whole scripting variable in JSP1.2 is
> > > poorly designed, and not well understood.
> >
> > The failures are from an app that worked perfectly fine with
> > jasper1, and with jasper2 ( up to 4.1.4 ).
> >
> > And IMHO are very elementary use cases - 2 iterates and one
> > condition is not that infrequent.
> >
>
> jasper1 and old jasper2 implements scripting variables by declaring them
> when a tag handler is instantiated, inside a block of its own, like
My problem is that code that worked with jasper1 no longer works with
jasper2.
And I believe the use case is valid and within the spec, and quite
common.
The latest failure is just 2 iterate tags and a condition tag -
I think it should work.
Costin
>
> {
> String x; // variable x defined here
> ...
> }
>
> This implementation has 2 problems.
>
> 1) Nested tags with same variable does not work
>
> <mytag:foo>
> <mytag:foo>
> </mytag:foo>
> </mytag:foo>
>
> because you cannot have two varibles of the same name in Java, even if
> they are in blocks nested within one another.
>
> 2) The variables are out of scope when the tag ends, but for variables
> with AT_BEGIN scope, spec says they should be accessable until the
> end of the page.
>
> >
> > > > How do we deal with nested tags of different type ? I don't have
> > > > a test case, but I assume someone may have a NESTED tag
> > > > 'foo' in 2 different tags, with different declared types ( String and
> > > > Integer ). The current generator seems to not create { },
> > > > and I'm not sure how this will work.
> > > >
> > > > ( no test case - but I'm sure you can find such tags )
> > > >
> > >
> > > That would not work, and would never be made to work, not only for
> > > nested case, but also for non-nested tags with AT_BEGIN scopes.
> > > I tend to think this falls into the user's reponsibility if she uses
> > > the same variable name for two different types, somewhat analogous to
> > > declaring two variables of the same name two different types in Java.
> >
> > I'm lost here - wasn't NESTED supposed to define a lexical scoping ?
> > I don't see why this wouldn't work - are you saying it doesn't
> > work with jasper2, it didn't worked with jasper1, or is not
> > required by the spec ?
> >
>
> You cannot have
>
> {
> String x;
> {
> String x;
> }
> }
>
> in Java, so we are implementing scripting variables with nested scopes as
>
> {
> String x;
> {
> String temp = x;
> ...
> }
> x = temp;
> }
>
> You can see why we'll have problems if two variables nesting with one
> anothers have the same name but different types.
>
> >
> > > Hopefully, there won't be a need for scripting variables anymore when
> > > expression language becomes available in JSP2.0.
> >
> > :-)
> >
> > Unfortunately JSP1.x will be around for a while, and jasper must support
> > it.
> >
> > Costin
> >
>
>
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