I've looked into it a bit. Visualworks smalltalk documentation gave me an idea[1].
In Smalltalk everything is an object, that is including numbers, characters etc. The standar method-lookup searches from the innermost class methods to the outermost class methods.
The method finder could simply iteratively go through all applicable methods that return the class requested and match results.
I don't recall reading about it anywhere, but I did once look at the implementation (it's wonderful having a reflective system where a single click gets you source of anything onscreen), and it's very straightforward but also kind of gross.
One neat trick I'd forgotten is that if it doesn't find anything interesting with the inputs in the order written, it permutes them and tries again!
In Smalltalk everything is an object, that is including numbers, characters etc. The standar method-lookup searches from the innermost class methods to the outermost class methods.
The method finder could simply iteratively go through all applicable methods that return the class requested and match results.
[1]: http://esug.org/data/Old/vw-tutorials/vw25/vw25ug.pdf (page 42 method-lookup)