>> 3) Search for procedures by argument name. This would not be perfect
>
> I think you'll be out of luck as I bet most of the times the name of
> the parameter is more a hint to its actual type than anything else...

Yes, I meant it mostly as a poor man's type signature search :) E.g.
search for "filename" to find procedures that deal with files. Obviously
a better type search can be done with a big manual effort. I wouldn't
extract type names only to do this, but we'll get this search for free
if the index has them.

>> That sounds quite advanced :) Is there a circular list detector?
>
> In general it can easily be implemented (while recursing over the
> inputs) by using something like:

I meant static detection knowing just the types and procedures. But I
guess one could implement design-by-contract (runtime assertions) or
just annotate types for documentation purposes even if we don't have
static checking.