PreparedGeometry and const

[Paul Ramsey]

Have a gander at the PreparedGeometry.h file.
It asserts that all the prepared predicates are const.
Have a gander at the implementation of, say, PreparedPolygon::intersects()
It naturally also declares itself to be const, but it calls the “static” function PreparedPolygonIntersects::intersects(this, g):
Which in turn instantiates a PreparedPolygonIntersects object, and then calls back to prepPoly->getIntersectionFinder(), which lazily creates a FastSegmentSetIntersectionFinder on the PreparedPolygon… which makes the whole thing not actually const, the state of the system is changing.
I assume this is managed by the strange two-step of the const function calling the static function that in turn reaches back and mutates its caller. 

I wouldn’t care except I’d like to add a RelateNG implementation for some of the currently unsupported predicates and I would like to not have to do so with all this “pretend const” infrastructure.

Does anyone know why all these pretty clearly non-const methods are declared const? Anyone have objections to removing the const keyword for these things? I have no idea how deep into the codebase such a removal would reach, but I’m guessing “not far”, the only folks who might be affected are C++ API users who have direct use of PreparedGeometry.

Thoughts?

P