I've used the grammarkit to build a custom language integration for the R language. Now I would love to allow for language injection into string literals. I've already prepared my grammar definition to generate a psiclass for string literals. However, I've no real idea how to implement the LangInjectPsiElement interface.
The javadoc of PsiLanguageInjectionHost states that for string literal injection the interface does need to be implemented at all. So maybe it's just about tagging by psiclass in some fancy way and registering it in some extension point?
Could somebody provide a minimalistic example about how to do enable language injection for string literals in custom language plugins? Or lead me to an easy/good example?