I have this code to do timing tests:

def tm(code); s=Time.now; eval code; Time.now-s end

I use it like this:

tm 'some code'

I have this function that can take two inputs.
When I  run it with just one input like this:

tm 'Pn(130)'

I can time it with no problems.

When I use a second input like this,

tm 'Pn(130, mcps)'

running in irb (1.8.6 and 1.9.0-1) it returns an
unknown method or variable message for the
second input.

Is this a bug, or expected behavior?
Can  I work around this?

Thanks in advance.