Why do PSI element types have to have a separate interface and an implementation class?

Sofe2038

创建于 2018年05月26日 15:55

I don't use GrammarKit BNF in my custom language parser, so I create the PSI element type classes manually, and I don't want to spend the effort creating two files for the same element type. Is there any reason or restriction?

In addition, I am writing a reference contributor, but PlatformPatterns.psiElement() is only matching the PsiComment elements in my file, where the PsiComments are the only non-custom element type used in my custom language (apart from whitespaces). I am not sure if this bug is related to not separating interfaces and implementations.

4 条评论

Gregory Shrago

创建于 2018年05月30日 13:32

There's no such restriction. One can use implementation classes directly.

Please add some snippets to illustrate the problems.

Sofe2038

创建于 2018年05月31日 06:12

I even System.out.println() directly to check what elements I have traversed:

https://github.com/SOF3/libglocal-idea-plugin/blob/master/src/io/github/sof3/libglocal/idea/ref/LibglocalReferenceContributor.java#L19

No errors spotted in the event log, live idea.log (in IntelliJ's Run tool window) or main output. I'm using PhpStorm.

I used PsiViewer to make sure the file consists not only comment elements.

Gregory Shrago

创建于 2018年06月01日 13:29

References are a completely different story.

Each psi implementation shall opt in for provided references explicitly.

See https://github.com/JetBrains/intellij-community/blob/master/java/java-psi-impl/src/com/intellij/psi/impl/source/tree/java/PsiLiteralExpressionImpl.java#L216

Sofe2038

创建于 2018年07月02日 04:25

So the full steps are:

Override getReferences() and return

PsiReferenceService.getService().getContributedReferences(this)

Implement
```
ContributedReferenceHost
```
PsiReferenceRegistrar.registerReferenceProvider() to handle the reference contribution

Thanks, this works.

But why aren't the first 2 steps mentioned in the tutorial?

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