Unity script for machine translation using the Yandex Translate API

YTranslate.cs

using System.Collections;
using System;
using System.Xml;
using UnityEngine.Networking;

/*
Requirement:
    Yandex Translate API key (https://tech.yandex.com/translate/)

Usage:
    YTranslate translator = new YTranslate(apiKey);
    string text = "Hello world";
    StartCoroutine(translator.translate(text, YTranslate.Language.ES, result => {
        Debug.Log(result.translatedText);
    }));
    
*/
public class YTranslate {
	private string apiKey;

	public YTranslate(string apiKey) {
		this.apiKey = apiKey;
	}

	public class Result {
		public
		const int
		NETWORK_ERROR = -1,
		SUCCESS = 200,
		INVALID_API_KEY = 401,
		BLOCKED_API_KEY = 402,
		DAILY_REQUESTS_EXCEEDED = 403,
		DAILY_TEXT_EXCEEDED = 404,
		TEXT_LENGTH_EXCEEDED = 413,
		CANNOT_TRANSLATE = 422,
		UNSUPPORTED_DIRECTION = 501;

		public readonly int status;
		public readonly Language language;
		public readonly string translatedText;

		public Result(int status, Language language, string translatedText) {
			this.status = status;
			this.language = language;
			this.translatedText = translatedText;
		}
	}

	public IEnumerator translate(string text, Language to, System.Action < Result > callback) {
		return translate(text, null, to, callback);
	}

	public IEnumerator translate(string text, Language ? from, Language to, System.Action < Result > callback) {
		string encodedText = UnityWebRequest.EscapeURL(text);
		string lang = ((from != null ? Enum.GetName(typeof(Language), from) + "-": "") + Enum.GetName(typeof(Language), to)).ToLower();
		string requestUrl = string.Format("https://translate.yandex.net/api/v1.5/tr/translate?key={0}&text={1}&lang={2}", apiKey, text, lang);
		UnityWebRequest request = UnityWebRequest.Get(requestUrl);
		yield
		return request.SendWebRequest();
		Result result;
		if (request.isNetworkError) {
			result = new Result(Result.NETWORK_ERROR, to, null);
		} else {
			string responseText = request.downloadHandler.text;
			XmlDocument doc = new XmlDocument();
			doc.LoadXml(responseText);

			XmlNode translation = doc.SelectSingleNode("Translation");
			XmlNode error = doc.SelectSingleNode("Error");

			int status;
			string translatedText;

			if (translation != null) {
				status = int.Parse(translation.Attributes["code"].Value);
				translatedText = doc.SelectSingleNode("Translation/text").InnerText;
			} else {
				status = int.Parse(error.Attributes["code"].Value);
				translatedText = null;
			}
			result = new Result(status, to, translatedText);
		}
		callback(result);
	}

	public enum Language {
		SQ,
		EN,
		AR,
		HY,
		AZ,
		AF,
		EU,
		BE,
		BG,
		BS,
		CY,
		VI,
		HU,
		HT,
		GL,
		NL,
		EL,
		KA,
		DA,
		HE,
		ID,
		GA,
		IT,
		IS,
		ES,
		KK,
		CA,
		KY,
		ZH,
		KO,
		LA,
		LV,
		LT,
		MG,
		MS,
		MT,
		MK,
		MN,
		DE,
		NO,
		FA,
		PL,
		PT,
		RO,
		RU,
		SR,
		SK,
		SL,
		SW,
		TG,
		TH,
		TL,
		TT,
		TR,
		UZ,
		UK,
		FI,
		FR,
		HR,
		CS,
		SV,
		ET,
		JA
	};
}