Sapling source-code management system - no staging area?

When there staging area is empty:

* git commit does nothing, so it has no equivalent.
* git commit -a is equivalent to hg commit
* git add [file] is equivalent to hg commit --secret [file]
* git add -p is equivalent to hg commit -i
* git reset --mixed does nothing, so it has no equivalent.
* If a file is newly created or deleted, you have to run hg add/remove on it. hg forget will stop tracking a file without deleting it. This also applies to the nonempty case.

When the staging area is nonempty:

* git commit is equivalent to hg phase -d . (last argument is a dot and is the hg equivalent of HEAD)
* git commit -a is equivalent to hg phase -d . && hg amend (commands can be run in either order)
* git add [file] is equivalent to hg amend [file]
* git add -p is equivalent to hg amend -i
* git reset --mixed is equivalent to hg uncommit --no-keep
* Since the staging area has a description like any other commit, you might want to change it. hg amend -e will change the description, but also does a regular amend; you can pass additional arguments to tell it not to include any files in the amend, or make an alias for that if you need to do it frequently.

Bonus feature: You can stack multiple staging areas on top of each other, by using commit instead of amend. Git can't do that without using something like stash, which requires you to fiddle with an entirely different set of commands.