confgen: support multi-key map

[Kybxd]

Sometimes we want to map multiple different keys to the same value, but we don't want to occupy too many cells. So we expect keys with the same value can be defined in the same cell. For example:

Group1ItemID	Group1ItemWeight	Group2ItemID	Group2ItemWeight	Group3ItemID	Group3ItemWeight
map<uint32, Group>|{multikey:true}	int32	uint32	int32	uint32	int32
Group1’s ItemID	Group1’s ItemWeight	Group2’s ItemID	Group2’s ItemWeight	Group3’s ItemID	Group3’s ItemWeight
101,102,103	100	201,202	200	301	300

This worksheet generates proto:

message ItemConf {
  option (tableau.worksheet) = {name:"ItemConf"};

  map<uint32, Group> group_map = 1 [(tableau.field) = {name:"Group" key:"ItemID" layout:LAYOUT_HORIZONTAL prop:{multikey:true}}];
  message Group {
    uint32 item_id = 1 [(tableau.field) = {name:"ItemID"}];
    int32 item_weight = 2 [(tableau.field) = {name:"ItemWeight"}];
  }
}

And json:

{
    "groupMap": {
        "101": {
            "itemId": 101,
            "itemWeight": 100
        },
        "102": {
            "itemId": 102,
            "itemWeight": 100
        },
        "103": {
            "itemId": 103,
            "itemWeight": 100
        },
        "201": {
            "itemId": 201,
            "itemWeight": 200
        },
        "202": {
            "itemId": 202,
            "itemWeight": 200
        },
        "301": {
            "itemId": 301,
            "itemWeight": 300
        }
    }
}

[wenchy]

The multikey-map concept is confused. By default, keys are guaranteed to be unique.

1. Multi same keys to different values

• C++ std::multimap

2. An unique composite key (which contains multiple keys) to a value

A data structure to store values with multiple keys in a map.

• Apache MultiKeyMap

So, we should define a accurate and clear naming but not multikey.

[wenchy]

Maybe there is a workaround solution, just use the index on incell scalar list feature?

Group1ItemID	Group1ItemWeight	Group2ItemID	Group2ItemWeight	Group3ItemID	Group3ItemWeight
[Group][uint32]	int32	uint32	int32	uint32	int32
Group1’s ItemID	Group1’s ItemWeight	Group2’s ItemID	Group2’s ItemWeight	Group3’s ItemID	Group3’s ItemWeight
101,102,103	100	201,202	200	301	300

[Kybxd]

Maybe there is a workaround solution, just use the index on incell scalar list feature?

Group1ItemID Group1ItemWeight Group2ItemID Group2ItemWeight Group3ItemID Group3ItemWeight
[Group][uint32] int32 uint32 int32 uint32 int32
Group1’s ItemID Group1’s ItemWeight Group2’s ItemID Group2’s ItemWeight Group3’s ItemID Group3’s ItemWeight
101,102,103 100 201,202 200 301 300

This is a different but feasible solution, since index works on all map levels (implemented in tableauio/loader#141).