[cfe-dev] (no subject)

[Eric Liu via cfe-dev]

Please read the documentation of `Replacements::add()` interface for
definition of `conflict` and possible ways to to deal with such conflict.

For your use case specifically, here is a way to handle this:
https://github.com/llvm-mirror/clang-tools-extra/blob/master/include-fixer/IncludeFixer.cpp#L385

And you are right, we do need a way to control the order of insertions, but
tooling::Replacements is not the right level of abstraction here. I am work
on a structure that is one layer higher and will come with an interface for
this.

On Wed, Nov 16, 2016 at 3:55 AM Steven Lu <stevenlu443 at gmail.com> wrote:

> I wonder if the logic behind the conflict is that multiple replacements
> (which are effectively additions as they remove zero characters) placed in
> the same location makes it unclear which order to apply them in.
>
> It would indeed be useful to have a way to control this. Is there a
> mechanism for it?
>
> On Tue, Nov 15, 2016 at 9:53 PM, Steven Lu <stevenlu443 at gmail.com> wrote:
>
> Thanks!
>
> Now that I can see the errors, they say that my replacements conflict with
> each other.
>
> It seems to me that if I make multiple replacements placed at the same
> location, which all replace zero characters, this shouldn't be treated as a
> conflict. This is in fact what I am seeing. Could you comment on that?
>
> Am I to understand that the replacement subsystem is in a state of flux at
> the moment?
>
> Thanks a lot!
> Steven
>
> On Tue, Nov 15, 2016 at 2:06 PM, Eric Liu <ioeric at google.com> wrote:
>
> You can use "llvm::toString(std::move(Err))" to convert the returned error
> to string.
>
> Thanks for pointing this out :) I'll mention this in the doc.
>
> On Tue, Nov 15, 2016 at 7:40 PM Steven Lu <stevenlu443 at gmail.com> wrote:
>
> I do have one more question.
>
> The return value of add() is an llvm::Error.
>
> I'm now finally able to compile the code, but I'm having a ton of trouble
> figuring out how to print such an error to a string stream of any kind.
> Google is no help here.
>
> Thanks!
>
> On Mon, Nov 14, 2016 at 4:06 PM, Steven Lu <stevenlu443 at gmail.com> wrote:
>
> Hi Eric,
>
> Thanks for clarifying. The only confusion I have is that previously the
> API was easier to use. Now I have to call Replacement.getFilePath() and
> explicitly index the filename map. It feels almost like maybe instead of
> getReplacements() returning a std::map maybe this could be (yet another)
> class so we can continue to have this straightforward interface.
>
> It also prompts me to wonder what other use cases that this change helps
> with.
>
> As for doc I'm sure that just adding a note of what you said (use
> Replacement.getFilePath() to index to the map) would have been enough to
> get me there. I hadn't realized that Replacement could fetch the file path.
>
> Thanks
>
> On Mon, Nov 14, 2016 at 6:30 AM, Eric Liu <ioeric at google.com> wrote:
>
> A common way is to use the file path in a replacement, i.e.
> `Replaces[R.getFilePath()].add(R)`. Note that clang::tooling::Replacements
> <https://github.com/llvm-mirror/clang/blob/master/include/clang/Tooling/Core/Replacement.h#L146>
> is now implemented as a class instead of a std::set.
>
> In general, `formatAndApplyAllReplacements` is a function you would use to
> apply changes while format changed code *after* you've got all replacements.
> A sample usage can be found in clang-move
> <https://github.com/llvm-mirror/clang-tools-extra/blob/master/clang-move/tool/ClangMoveMain.cpp#L137>.
> And I think the interface's comment does explain its purpose. Which
> specific part did you find confusing? I'm happy to improve the doc :)
>
> - Eric
> On Mon, Nov 14, 2016 at 12:04 PM Manuel Klimek <klimek at google.com> wrote:
>
> +eric
>
>
> On Sat, Nov 12, 2016 at 10:45 AM Steven Lu via cfe-dev <
> cfe-dev at lists.llvm.org> wrote:
>
> I've updated clang from revision 254425 to 286122, and RefactoringTool::getReplacements()
> now produces a map of files to replacements.
>
> My original code implements a MatchFinder::MatchCallback which takes a
> pointer to the return value of RefactoringTool::getReplacements() and
> simply inserts Replacements, now it is not clear how I am to perform the
> insertion, I cannot tell now if there is some canonical way to determine
> the filename string to save a particular Replacement under.
>
> I have also found the function formatAndApplyAllReplacements which I'm
> having trouble finding doc/instructions for and seems to be a highest-level
> function that I should use, but it doesnt seem to help address this
> problem.
>
> I wonder if someone could do a quick rundown of how to use the interface
> in a proper way.
>
> Thanks
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