
doc:   [
    DocGroup({"tag": "h1"}, [
        DocChars("Hello world!")
    ]),
    DocGroup({"tag": "p"}, [
        DocChars("What\'s up with you?")
    ])
]

a_del: [
    DelGroup([
        DelChars(2), DelSkip(6), DelChars(4)
    ]),
    DelGroup([
        DelChars(3), DelSkip(16)
    ])
]
a_add: [
    AddGroup({"tag": "h3"}, [
        AddGroup({"client": "a", "tag": "caret"}, []),
        AddChars(" "), AddGroup({"client": "b", "tag": "caret"}, []),
        AddChars("j"), AddGroup({"client": "c", "tag": "caret"}, []),
        AddChars(" ")
    ]),
    AddGroup({"tag": "bullet"}, [
        AddGroup({"tag": "h3"}, [
            AddChars(" "), AddSkip(6), AddChars(" 5")
        ]),
        AddGroup({"tag": "h3"}, [
            AddSkip(16)
        ])
    ])
]

b_del: [
    DelGroup([
        DelSkip(12)
    ]),
    DelGroup([
        DelSkip(19)
    ])
]
b_add: [
    AddGroup({"tag": "bullet"}, [
        AddGroup({"tag": "h1"}, [
            AddChars(" "), AddGroup({"tag": "caret", "client": "d"}, []),
            AddChars("L"), AddSkip(12), AddChars("0n"), AddSkip(19)
        ])
    ])
]
