[PATCH] Add support for polymorphic matchers.

[Samuel Benzaquen]

On Wed, May 15, 2013 at 1:57 AM, Manuel Klimek <klimek at google.com> wrote:

> On Tue, May 14, 2013 at 9:35 PM, Samuel Benzaquen <sbenza at google.com>wrote:
>
>>
>>
>> ================
>> Comment at: lib/ASTMatchers/Dynamic/DynMatchers.cpp:35
>> @@ +34,3 @@
>> +          ast_matchers::internal::BoundNodesTreeBuilder *Builder) const {
>> +    return M1->matches(DynNode, Finder, Builder) ||
>> +        M2->matches(DynNode, Finder, Builder);
>> ----------------
>> Manuel Klimek wrote:
>> > How much harder would it be to not re-implement the matchers? I'd like
>> to keep matcher implementations as cohesive as possible, as we want to be
>> able to change the implementations when we introduce new features.
>> The ones that are easier to reimplement are the ones that are way too
>> generic, like anything() or equals().
>>
>> anything() returns a polymorphic matcher which is not a DynTypedMatcher.
>> I don't have specific Ts to create a Matcher<T> from anything(). I could
>> list all possible types (the ones that DynTypedNode supports) and merge
>> them, but it seemed to me that a reimplementation of it would be simpler.
>>
>
> I agree it's easier to implement. I don't agree it'll be easier to
> maintain. The problem is that some matchers (forEach*, has, etc) have
> specific ways in which they affect binding of nodes.
>

Ok. I understand your point.
This CL didn't really handle has/forEach/etc other than putting them on a
list of "to reimplement". I'll investigate later how to handle the
"adaptative matchers" another way.


> I definitely don't want to duplicate that logic anywhere. Thus, I'd prefer
> if we'd find a way to support those fully polymorphic matchers by
> generating the dynamic ones for all types they can possibly match on
> (perhaps we can just wrap them with something that works on
> DynTypedMatcher?)
>

Would it be ok if the solution is to have these be implemented in a dynamic
way and have the polymorphic/adaptative type-safe wrappers for statically
bound code?
I don't know if it is simpler to code/maintain, just wanted to know if you
would be ok with that possibility.

_Sam
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