Support foundation javac

[sormuras]

Is it possible to abstract the underlying compiler to allow usage of provided javac tool?

It would enable supporting new Java syntax (like Text Blocks et al.) out of the box, wouldn't it?

Related issues:

• Support for switch expressions (JEP 361) #340 switch-expressions as a preview since Java 12
• Support Text Blocks (JEP 368) #382 """Text Blocks""" as a preview since Java 13-ea

[cushon]

The implementation uses internal APIs from the jdk.compiler module, not just the public java.compiler ones, so using the implementation from the host JDK would require passing additional flags to disable module access checks. It would also mean the formatter had to support a range of versions of the internal APIs, which is difficult because there can be breaking changes between releases.

Also, this would only solve half of the problem for new language features: having a parser that handles switch expressions and text blocks isn't sufficient, the formatting logic still has to be updated to decide what to do with those constructs.

[eaftan]

Closing as Infeasible

[cushon]

After thinking about this more, it may be part of the solution after all. Let's continue the discussion in #436.