Searching inside scala 2.10 ASTs

Question

What's the best way to recursively search for an element in scala 2.10 ASTs?

The trees might be a result of power.trees(code) or mirror.mkToolBox().parseExpr(code) Edit. In 2.10.0-RC1 parseExpr has been renamed to parse.

The concrete use-case that I have is extracting the code of a method from a given class/object code by method name, but I assume that the question would be more relevant for others if formulated in a more generic way.

Answer 1

Maybe you should have a look at https://github.com/scala/scala/blob/2.10.x/src/reflect/scala/reflect/api/Trees.scala#L606, especially at the classes Traverser, Transformer and the methods for substitution (Tree.substituteSymbols, Tree.substituteTypes or Tree.substituteThis). If you want to extract a method from a tree, you can use a Traverser and override the traverse method. In the traverse method, you check whether the node matches the method you want. If so, you are done. If not, you call super.traverse.