> FWIW I'm using current-milliseconds in place of the non existant runtime.
Also FWIW: I'm rolling my own Scheme in Ruby to play along with SICP.
I seem to remember getting all zeros on benchmarking in PLT because it
was too fast; fortunately mine's slow enough to give you decent
numbers! It has (runtime) which returns microseconds, and enough code
to do chapter 1 of SICP. I'm working on macros and continuations, any
Ruby hackers feel like playing with it can get it on github: