Enum inference metric too conservative?

[rjstelling]

I have the below JSON and using this command:

$ quicktype --alphabetize-properties --density normal --no-initializers --src example.json --lang swift --top-level "Certificate" -o out.swift

I don't not get enums for Switch.type (see output below).

Input

{
    "expires": 1519873431,
    "modules": [
        {
            "name": "FPKit",
            "switches": [
                {
                    "key": "valueA",
                    "type": "string",
                    "type_info": null,
                    "value": "hello world"
                },
                {
                    "key": "valueB",
                    "type": "string",
                    "type_info": null,
                    "value": "hello world"
                },
                {
                    "key": "valueC",
                    "type": "string",
                    "type_info": null,
                    "value": "hello world"
                },
                {
                    "key": "valueD",
                    "type": "string",
                    "type_info": null,
                    "value": "hello world"
                },
                {
                    "key": "valueE",
                    "type": "string",
                    "type_info": null,
                    "value": "hello world"
                },
                {
                    "key": "valueF",
                    "type": "string",
                    "type_info": null,
                    "value": "hello world"
                },
                {
                    "key": "valueG",
                    "type": "string",
                    "type_info": null,
                    "value": "hello world"
                },
                {
                    "key": "valueH",
                    "type": "string",
                    "type_info": null,
                    "value": "hello world"
                },
                {
                    "key": "valueI",
                    "type": "string",
                    "type_info": null,
                    "value": "hello world"
                },
                {
                    "key": "valueJ",
                    "type": "string",
                    "type_info": null,
                    "value": "hello world"
                },
                {
                    "key": "value2",
                    "type": "int",
                    "type_info": null,
                    "value": "2"
                },
                {
                    "key": "value3",
                    "type": "double",
                    "type_info": null,
                    "value": "3.5"
                },
                {
                    "key": "value3a",
                    "type": "double",
                    "type_info": null,
                    "value": "3.5"
                },
                {
                    "key": "value4",
                    "type": "bool",
                    "type_info": null,
                    "value": "true"
                },
                {
                    "key": "value5",
                    "type": "data",
                    "type_info": null,
                    "value": "vafEXVIgdfg;svjKLIger/wFFFdfvkjadlluulfhj567gnlCWuukgj6dv5vCECWWaM,PiOEFGjdsv=="
                },
                {
                    "key": "value5a",
                    "type": "custom",
                    "type_info": "UIColor",
                    "value": "vafEXVIgdfg;svjKLIger/wFFFdfvkjadlluulfhj567gnlCWuukgj6dv5vCECWWaM,PiOEFGjdsv=="
                },
                {
                    "key": "value5b",
                    "type": "custom",
                    "type_info": "UIColor",
                    "value": "vafEXVIgdfg;svjKLIger/wFFFdfvkjadlluulfhj567gnlCWuukgj6dv5vCECWWaM,PiOEFGjdsv=="
                }
            ]
        },
        {
            "name": "main",
            "switches": [
                {
                    "key": "value",
                    "type": "string",
                    "type_info": null,
                    "value": "hello world"
                },
                {
                    "key": "value",
                    "type": "string",
                    "type_info": null,
                    "value": "hello world"
                },
                {
                    "key": "value2",
                    "type": "int",
                    "type_info": null,
                    "value": "2"
                },
                {
                    "key": "value3",
                    "type": "double",
                    "type_info": null,
                    "value": "3.5"
                },
                {
                    "key": "valuea",
                    "type": "string",
                    "type_info": null,
                    "value": "hello world"
                },
                {
                    "key": "valueb",
                    "type": "string",
                    "type_info": null,
                    "value": "hello world"
                },
                {
                    "key": "value2",
                    "type": "int",
                    "type_info": null,
                    "value": "2"
                },
                {
                    "key": "value3",
                    "type": "double",
                    "type_info": null,
                    "value": "3.5"
                },
                {
                    "key": "value4",
                    "type": "bool",
                    "type_info": null,
                    "value": "true"
                },
                {
                    "key": "value4",
                    "type": "bool",
                    "type_info": null,
                    "value": "true"
                },
                {
                    "key": "value5b",
                    "type": "data",
                    "type_info": null,
                    "value": "vafEXVIgdfg;svjKLIger/wFFFdfvkjadlluulfhj567gnlCWuukgj6dv5vCECWWaM,PiOEFGjdsv=="
                },
                {
                    "key": "value5a",
                    "type": "custom",
                    "type_info": "UIColor",
                    "value": "vafEXVIgdfg;svjKLIger/wFFFdfvkjadlluulfhj567gnlCWuukgj6dv5vCECWWaM,PiOEFGjdsv=="
                },
                {
                    "key": "valuec",
                    "type": "string",
                    "type_info": null,
                    "value": "hello world"
                }
            ]
        }
    ],
    "signature": "vafEXVIgdfg;fEXVIgdfg;svjKLbsfgbfs%$^&*YHkbjvgkccIger/;svjKLIger/wFFFdfvkFdfvkjCWWaM,PiGjdsv==",
    "version": 1
}

Output

// To parse the JSON, add this file to your project and do:
//
//   let certificate = try? JSONDecoder().decode(Certificate.self, from: jsonData)

import Foundation

struct Certificate: Codable {
    let expires: Int
    let modules: [Module]
    let signature: String
    let version: Int

    enum CodingKeys: String, CodingKey {
        case expires = "expires"
        case modules = "modules"
        case signature = "signature"
        case version = "version"
    }
}

struct Module: Codable {
    let name: String
    let switches: [Switch]

    enum CodingKeys: String, CodingKey {
        case name = "name"
        case switches = "switches"
    }
}

struct Switch: Codable {
    let key: String
    let type: String
    let typeInfo: String?
    let value: String

    enum CodingKeys: String, CodingKey {
        case key = "key"
        case type = "type"
        case typeInfo = "type_info"
        case value = "value"
    }
}

[dvdsgl]

I know this isn't what you're asking for, but FYI, we now support TypeScript input for more control over generated types. Given the file certificate.ts:

class Certificate {
    /** @TJS-type integer */
    expires:   number;
    modules:   Module[];
    signature: string;
    /** @TJS-type integer */
    version:   number;
}

class Module {
    name:     string;
    switches: Switch[];
}

class Switch {
    key:        string;
    type:       "string" | "custom" | "data" | "bool" | "double" | "int";
    type_info?: string;
    value:      string;
}

You can get the Swift you want with:

$ quicktype \
    --alphabetize-properties --density normal --no-initializers \
    --src certificate.ts --lang swift --top-level "Certificate" -o out.swift

Or more succinctly:

$ quicktype certificate.ts -o out.swift \
    --alphabetize-properties --density normal --no-initializers

[schani]

Our metric needs to see more values before it will infer type as an enum. Adding a few by hand works. Maybe it's too conservative?

[rjstelling]

Yes, tripling the "switches" sorted it.

Yes, I would say it was a bit conservative, maybe a threshold switch on the cli?