[cfe-dev] Creating AStMatcher from code ?

[mats petersson via cfe-dev]

Sorry about earlier message - premature "send"... :(

So, surely this is rather hard to do.

If you write match this: `class T; T* ptr = new T;`, what should it match?
Only the exact class called `T`? Or, the opposite extreme, any assignment
of new of any type, e.g "int *ptr = new int;"? What about "const X* p = new
Y;"? Or "std::vector<int*> a = { new int, new int }"?  What do you want to
do with `T* ptr{new T};` - it does essentially the same thing, but
syntactially and semantically, it's not identical - I'd expect the AST is
not identical - and if it is when you didn't want to match that, it's a
problem [although not solvable, since the AST is the same].

Of course these examples are mostly nonsense and can be solved in other
ways, I'm just trying to point out that "matching something" often means
distinguishing "This is what I want to match, this I don't care about" -
so, do you care if the type is `const` or not, do you care if the type is a
`class` or `struct` vs. `int` etc? Do you care if it's exactly an
assignment, or anything that "kind of assigns".

What I'm trying to say is that it would probably produce something to start
from, but I'm not convinced it is THAT much help, since you still have to
apply some fuzz and modify the code to do what you ACTUALLY want to do.

--
Mats

On 14 March 2016 at 14:48, mats petersson <mats at planetcatfish.com> wrote:

> Sure
>
> On 14 March 2016 at 14:11, Manuel Klimek via cfe-dev <
> cfe-dev at lists.llvm.org> wrote:
>
>> On Mon, Mar 14, 2016 at 2:50 PM David Come via cfe-dev <
>> cfe-dev at lists.llvm.org> wrote:
>>
>>> Hello,
>>>
>>> I have been playing a bit with lib ASTMatcher and it is very tedious to
>>> use.
>>> My workflow is to dump the AST  for the relevant code and translate it
>>> into matchers, using clang-query to make sure it works.
>>>
>>> I was wandering is there was any tool (or proposal, work in progress...)
>>> for automating this work.
>>> The end goal would be give it some C++ code as input and have the
>>> corresponding matcher in output.
>>>
>>
>> Unfortunately there is no such tool. Would be awesome to have, though :)
>>
>>
>>>
>>> Thanks,
>>> David
>>> _______________________________________________
>>> cfe-dev mailing list
>>> cfe-dev at lists.llvm.org
>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>>>
>>
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>>
>
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