[[!comment format=mdwn
 username="picca"
 subject="comment 1"
 date="2015-09-29T12:35:27Z"
 content="""
ok, so I created this property but it does not work

    sbuild :: System -> FilePath -> Property NoInfo
    sbuild system tarball =
      chroot `onChange` Tar.create chrootdir tarball
        where
          chroot = Chroot.debootstrapped system Debootstrap.BuilddD chrootdir
          chrootdir = \"/tmp/chroot\"

it fails with this error message

    src/config.hs:167:3:
        Couldn't match expected type `Property x0'
                    with actual type `Chroot.Chroot'
        In the first argument of `onChange', namely `chroot'
        In the expression: chroot `onChange` Tar.create chrootdir tarball

What I understand it that onChange expect a Property instead of a Chroot.
So what is the right way to tell propellor look at this chrootdir directory and create a tarball if its containt changed.
"""]]
