[cfe-dev] automatic bind for topmost matcher

[Manuel Klimek]

On Tue, Oct 23, 2012 at 11:05 AM, Philip Craig <philipjcraig at gmail.com>wrote:

> On Tue, Oct 23, 2012 at 7:04 PM, Manuel Klimek <klimek at google.com> wrote:
> > On Tue, Oct 23, 2012 at 11:00 AM, Philip Craig <philipjcraig at gmail.com>
> > wrote:
> >>
> >> On Tue, Oct 23, 2012 at 6:44 PM, Manuel Klimek <klimek at google.com>
> wrote:
> >> > On Tue, Oct 23, 2012 at 10:37 AM, Philip Craig <
> philipjcraig at gmail.com>
> >> > wrote:
> >> >>
> >> >> In a MatchCallback, is there any way of determining the topmost node
> >> >> that was matched without needing to bind it? This would merely be a
> >> >> convenience, similar to the way that regular expressions always
> return
> >> >> the complete match, and you only have to gives names to parts of the
> >> >> regular expression if you want the subexpressions.
> >> >
> >> >
> >> > Currently not, as you can always write .bind("x") very easily. What
> name
> >> > would you propose?
> >>
> >> My desire was to not need any name, so that I could just call
> >> Result.Nodes.getNodeAs<T>() without any argument.
> >>
> >> For the situation that prompted my question see
> >> http://llvm-reviews.chandlerc.com/D72. Always having access to the top
> >> node would avoid the need for the NodeVerifier class in that patch.
> >
> >
> > You'd still need a callback where you pull it out of the results,
> wouldn't
> > you?
>
> Yes, but I wouldn't need to tell the callback what name to use, and
> the callback wouldn't need to check whether a node with that name was
> bound, because the topmost node would always be bound.
>

If you don't do the bind into the test code, but sink it into where you
take the matcher (and make that the same class that does the verification,
perhaps using an inner class), you can have the bind("id") call and the
pulling out of the result into the same level of abstraction.

Even with a default binding, you'd still need to check that the node is
there, as the types might not match, right?

That said, I don't have a big problem with adding .bind("") to all
addMatcher calls in the ASTMatchFinder; I don't see how it would interfere
with anything - patch welcome :)

Cheers,
/Manuel
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