I don't know the internal architecture of the Eclipse compiler, but one of the points of the Roslyn architecture is to turn the compiler into an API, allowing t

I don't know the internal architecture of the Eclipse compiler, but one of the points of the Roslyn architecture is to turn the compiler into an API, allowing things like inserting plugins — custom linter rules, for example — at each point in the pipeline. Eclipse is interesting in that it grew out of IBM's VisualAge for Java, which was written in Smalltalk as an extension of the original VisualAge IDE/compiler, which goes back all the way to the mid-1980s. I wonder if any of the inspiration for this design came out of Smalltalk's runtime state being persistent. If all your state is derived from earlier state, then there's no need to always start processing from scratch, since you can just continue from where you were before.