audio rate envelope follower, always getting the highest peak without smoothing (always on time, you can still use a smooth2 to smooth out it's attack, though you'll go down to control-rate again). Not that the second "math/max" and "math/*" are just a doubling of the first part (after abs), this is to smooth out the output a bit more. You might also do with one, or use more if you need more smoothing.
-ratio (0 to full gain-reduction)
-make-up gain (when fully open, adds gain that boosts output back to 0dB after compression)
-max out (output max volume)
To add the regular attack/release controls, add an envelope-follower between the math/* and math/inv. The rise and fall times now correspond to attack and release, like normally, instead of inversed like the standard axoloti compressor.