In a pinch you can get a decent pedal to get you back on the road by gravity bleeding too.
Some people (or maybe it varies by vehicle?) can do a full 100% bleed with gravity, but I've only used it to get close enough to drive it until I could bleed normally.
You can sometimes do it with everything installed, or you can start the process while the calipers are connected to the hose (obviously!) but not yet mounted to the bracket.
Just hold it higher than the hard line, but lower than the master, open the bleeder and let it ooze out and purge the big air bubbles. Close the valve and install the caliper.
It can be a messy process, so you need to have a drip pan or something on the ground, and you likely don't want to do it with a freshly painted caliper (though I did!), but it does/can work.
I actually got mine pretty good that way the last time. Drove with a pretty decent pedal too. Although not quite as firm as before
It's probably not the best idea to rely on this as your main method, but if you're under the gun to get the job done and need to drive it a bit before you can get a helper or a power bleeder, it's a possible option.
Paul