Update: I've dropped most of the ideas mentioned here.
I'm toying with the idea of prefixing unsafe functions in swx with unsafe_ (example: unsafe_swx_mapper_match). I like how this makes explicit the fact that I'm testing unsafe functions (example: test_unsafe_swx_mapper_match). This is similar to the use of the exclamation (!) suffix in Scheme and Ruby. If this works well, I might do the same in inertia.
Couple of other things you might notice if you haven't done much programming in PHP are the swx in the function names that acts like a namespace for swx and the underscore (_) prefix in some function names (example: _unsafe_swx_mapper_pattern) that marks them as private functions for internal use only.