Tree structure:
[{
"ply": 1,
"san": "e4",
"comments": [],
"variations": []
}, {
"ply": 2,
"san": "d6",
"comments": [],
"variations": []
}, {
"ply": 3,
"san": "Nc3",
"comments": [],
"variations": [
[{
"ply": 3,
"san": "Nf3",
"comments": [],
"variations": []
}, {
"ply": 4,
"san": "Bg4",
"comments": [],
"variations": []
}, {
"ply": 5,
"san": "Be2",
"comments": [],
"variations": [
[{
"ply": 5,
"san": "Nc3",
"comments": [],
"variations": []
}]
]
}]
]
}, {
"ply": 4,
"san": "Nc6",
"comments": [],
"variations": []
},
...
]
Path structure:
[{
"ply": 3,
"variation": 1
}, {
"ply": 4,
"variation": null
}]
Here, the user is on the fourth ply, on the first variation of the third ply.