usable translations and Coeur DSL

project/MornyConfiguration.scala

@@ -8,7 +8,7 @@ object MornyConfiguration {
 	val MORNY_CODE_STORE = "https://github.com/Eyre-S/Coeur-Morny-Cono"
 	val MORNY_COMMIT_PATH = "https://github.com/Eyre-S/Coeur-Morny-Cono/commit/%s"
 	
-	val VERSION = "2.0.0-alpha18"
+	val VERSION = "2.0.0-alpha19"
 	val VERSION_DELTA: Option[String] = None
 	val CODENAME = "xinzheng"
 	

src/main/resources/assets_morny/langs/en_us.hyt

@@ -4,11 +4,26 @@
 &encoding=utf8
 &indent=1
 
+morny.information.about_links
+| <a href='{MORNY_SOURCECODE_LINK}'>source code</a> | <a href='{MORNY_SOURCECODE_SELF_HOSTED_MIRROR_LINK}'>backup</a>
+| <a href='{MORNY_ISSUE_TRACKER_LINK}'>Feedback / issue tracker</a>
+| <a href='{MORNY_USER_GUIDE_LINK}'>User's Guide / documentations</a>
+
 morny.command.info.message.about
 | <b>Morny Cono</b>
 | An assistant rat(micromys minutus) from Annie。
 | ————————————————
-| {about_links}
+| {morny.information.about_links}
+
+morny.command.info.sub_start.message
+| Welcome you meet the <b>Morny Cono</b>，<i>an assistant rat from Annie</i>。
+| Morny has a lot variety of features。
+|
+| ————————————————
+| {morny.information.about_links}
+| ————————————————
+|
+| （You can use /info command to get these message in any time）
 
 morny.command.info.version
 | version:
@@ -50,4 +65,4 @@ morny.command.info.message.tasks
 morny.command.info.message.event
 | <b>Event Statistics :</b>
 | in today
-| {event_statistics}""".stripMargin
+| {event_statistics}

src/main/resources/assets_morny/langs/zh_cn.hyt

@@ -4,8 +4,40 @@
 &encoding=utf8
 &indent=1
 
-morny.command.info.about
+morny.information.about_links
+| <a href='{MORNY_SOURCECODE_LINK}'>source code</a> | <a href='{MORNY_SOURCECODE_SELF_HOSTED_MIRROR_LINK}'>backup</a>
+| <a href='{MORNY_ISSUE_TRACKER_LINK}'>反馈 / issue tracker</a>
+| <a href='{MORNY_USER_GUIDE_LINK}'>使用说明书 / user guide & docs</a>
+
+morny.command.info.message.about
 | <b>Morny Cono</b>
 | 来自安妮的侍从小鼠。
 | ————————————————
-| {about_links}
+| {morny.information.about_links}
+
+morny.command.info.sub_start.message
+| 欢迎使用 <b>Morny Cono</b>，<i>来自安妮的侍从小鼠</i>。
+| Morny 具有各种各样的功能。
+|
+| ————————————————
+| {morny.information.about_links}
+| ————————————————
+|
+| （你可以随时通过 /info 重新获得这些信息）
+
+morny.misc.command_test.message
+| <b>这只是一个 /test 测试命令。</b>测试 <i>id</i> 为 <code>1</code>。
+| 你可以回复一条消息来测试回复消息的功能。
+
+morny.misc.command_test.branch_normal.message
+| 你完成了一个回复消息的测试！
+| 你所回复的消息为：
+| 
+| {replied_message}
+
+morny.misc.command_test.branch_oops.err_message_simple
+| 将会生成一条错误！ (使用 <b>/inspect</b> 命令来洞察错误详细信息)
+
+morny.misc.command_test.branch_oops.err_message_complex
+| Oops: There is just a test error.
+| 这个错误是由 <b>/test</b> 命令手动触发的，为了测试错误洞察命令是否可以正常工作。

src/main/resources/assets_morny/langs/zh_tw.hyt

@@ -0,0 +1,16 @@
+	Morny Translations File
+
+%1.0
+&encoding=utf8
+&indent=1
+
+morny.information.about_links
+| <a href='{MORNY_SOURCECODE_LINK}'>source code</a> | <a href='{MORNY_SOURCECODE_SELF_HOSTED_MIRROR_LINK}'>backup</a>
+| <a href='{MORNY_ISSUE_TRACKER_LINK}'>回饋 / issue tracker</a>
+| <a href='{MORNY_USER_GUIDE_LINK}'>使用說明書 / user guide & docs</a>
+
+morny.command.info.message.about
+| <b>Morny Cono</b>
+| 來自安妮的侍從小鼠。
+| ————————————————
+| {morny.information.about_links}

src/main/scala/cc/sukazyo/cono/morny/core/MornyCoeur.scala

@@ -2,7 +2,7 @@ package cc.sukazyo.cono.morny.core
 
 import cc.sukazyo.cono.morny.core.Log.logger
 import cc.sukazyo.cono.morny.core.MornyCoeur.*
-import cc.sukazyo.cono.morny.core.bot.api.{EventListenerManager, MornyCommandManager, MornyQueryManager}
+import cc.sukazyo.cono.morny.core.bot.api.{BotExtension, EventListenerManager, MornyCommandManager, MornyQueryManager}
 import cc.sukazyo.cono.morny.core.bot.api.messages.ThreadingManager
 import cc.sukazyo.cono.morny.core.bot.event.{MornyOnInlineQuery, MornyOnTelegramCommand, MornyOnUpdateTimestampOffsetLock}
 import cc.sukazyo.cono.morny.core.bot.internal.{ErrorMessageManager, ThreadingManagerImpl}
@@ -15,6 +15,7 @@ import cc.sukazyo.cono.morny.util.time.WatchDog
 import cc.sukazyo.cono.morny.util.GivenContext
 import cc.sukazyo.cono.morny.util.UseString.MString
 import cc.sukazyo.cono.morny.util.UseThrowable.toLogString
+import cc.sukazyo.cono.morny.util.hytrans.Translations
 import com.pengrad.telegrambot.TelegramBot
 import com.pengrad.telegrambot.request.GetMe
 
@@ -127,6 +128,12 @@ class MornyCoeur (modules: List[MornyModule])(using val config: MornyConfig)(tes
 		)}
 		   |"""
 	
+	///>>> BLOCK START local storage / data configuration
+	
+	val lang: MornyLangs = MornyLangs()
+	
+	///>>> BLOCK END local storage / data configuration
+	
 	///>>> BLOCK START instance configure & startup stage 1
 	
 	logger `info` "Coeur starting..."
@@ -324,6 +331,47 @@ class MornyCoeur (modules: List[MornyModule])(using val config: MornyConfig)(tes
 	
 	///<<< BLOCK END instance configure & startup stage 2
 	
+	/** Provide DSLs of Morny Coeur
+	  *
+	  * Provide the following coeur values to using/given context:
+	  *
+	  *  - Coeur itself
+	  *  - its Telegram bot account: [[MornyCoeur.account]]
+	  *  - its i18n translation instance: [[MornyCoeur.lang.translations]]
+	  *
+	  * Also provides the DSLs defined in [[BotExtension]].
+	  *
+	  * You can simply add the following line to use the vals and DSL functions in your code:
+	  *
+	  * {{{
+	  *     // assuming the Coeur instance is coeur
+	  *     import coeur.dsl.given
+	  *
+	  *     // now you can use the vals in your code
+	  *     translations.trans(/* ... */)
+	  *     // or use as an implicit/using value
+	  *     import com.pengrad.telegrambot.request.SendMessage
+	  *     import cc.sukazyo.cono.morny.util.tgapi.TelegramExtensions.Requests.unsafeExecute
+	  *     SendMessage(/* ... */)
+	  *         .unsafeExecute // implicitly use coeur.account
+	  *
+	  *     // you need to use the * import to use DSL functions
+	  *     import coeur.dsl.*
+	  *     // or use the following line to import both vals and DSL functions
+	  *     import coeur.dsl.{*, given}
+	  *
+	  *     // now you can use the DSL functions in your code
+	  *     import com.pengrad.telegrambot.model.User
+	  *     val prefer_languge = user.asInstanceOf[User].prefer_language
+	  *
+	  * }}}
+	  */
+	object dsl extends BotExtension {
+		given coeur: MornyCoeur = MornyCoeur.this
+		given account: TelegramBot = MornyCoeur.this.account
+		given translations: Translations = MornyCoeur.this.lang.translations
+	}
+	
 	def saveDataAll(): Unit = {
 		modules.foreach(it => it.onRoutineSavingData)
 		logger `notice` "done all save action."
@@ -396,7 +444,8 @@ class MornyCoeur (modules: List[MornyModule])(using val config: MornyConfig)(tes
 					logger `info` s"Succeed logged in to @${remote.username}"
 					break(Some(LoginResult(account, remote.username, remote.id)))
 				} catch
-					case r: boundary.Break[Option[LoginResult]] => throw r
+					/* boundary.Break[Option[LoginResult] */
+					case r: boundary.Break[_] => throw r
 					case e: Throwable =>
 						logger `error`
 							s"""${e.toLogString}

src/main/scala/cc/sukazyo/cono/morny/core/MornyLangs.scala

@@ -0,0 +1,68 @@
+package cc.sukazyo.cono.morny.core
+
+import cc.sukazyo.cono.morny.core.Log.logger
+import cc.sukazyo.cono.morny.data.MornyAssets
+import cc.sukazyo.cono.morny.util.hytrans.*
+import cc.sukazyo.cono.morny.util.UseThrowable.toLogString
+
+import java.io.IOException
+import scala.collection.mutable
+import scala.util.boundary
+import scala.util.boundary.break
+
+class MornyLangs {
+	
+	private val (lang_index, lang_trans) = {
+		
+		logger `info` s"Loading Morny's translation data."
+		
+		val (lang_dir, lang_index_content) = try {(
+			MornyAssets.pack.getResDir("langs"),
+			MornyAssets.pack.getResource("langs/_index.hyl").readAsString()
+		)} catch case e: IOException =>
+			throw Exception("Cannot read Morny's translations file.", e)
+		val my_index = LanguageTree.parseTreeDocument(lang_index_content)
+		val indexed_langs: Set[String] = {
+			val lang_tags = mutable.ListBuffer.empty[String]
+			my_index.root.traverseTree(lang_tags += _.langTag.lang)
+			logger `info` s"indexed following languages: ${lang_tags.mkString(", ")}"
+			lang_tags.toSet
+		}
+		
+		val language_translations = mutable.HashMap.empty[String, Definitions]
+		
+		for (file <- lang_dir.listFiles().filter(_.isFile)) yield { boundary {
+			import file.getPath as raw_path
+			if !(raw_path.endsWith(".hyt") || raw_path.endsWith(".hytrans")) then break()
+			val file_name = file.getPath.reverse.takeWhile(c=>(c!='/')&&(c !='\\')).reverse
+			val file_basename = file_name.dropRight(
+				if file_name.endsWith(".hyt") then ".hyt".length
+				else ".hytrans".length
+			)
+			val normalized = LangTag.normalizeLangTag(file_basename)
+			if !indexed_langs.contains(normalized) then
+				logger `warn` s"translation file \"$file_name\" is not in language index, so it got ignored (normalized lang name is \"$normalized\")."
+				break()
+			val lang_def = try {
+				val content = file.readAsString()
+				Parser.parse(content)
+			} catch case e: IOException =>
+				logger `error`
+					s"""Failed read/parse translation file $file_name (normalized lang name is $normalized):
+					   |${e.toLogString.indent(2)}
+					   |due to failed, this ($file_name) has been ignored.""".stripMargin
+				break()
+			logger `info` s"read language file $file_name (normalized lang name is $normalized), with ${lang_def.size} entries."
+			if language_translations contains normalized then
+				// TODO: merge
+				logger `warn` s"  language $normalized seems already loaded one yet, this will override the old one!"
+			else language_translations += (normalized -> lang_def)
+		}}
+		
+		(my_index, language_translations.toMap)
+		
+	}
+	
+	val translations: Translations = Translations(lang_index, lang_trans)
+	
+}

src/main/scala/cc/sukazyo/cono/morny/core/bot/api/BotExtension.scala

@@ -2,10 +2,13 @@ package cc.sukazyo.cono.morny.core.bot.api
 
 import cc.sukazyo.cono.morny.core.MornyCoeur
 import cc.sukazyo.cono.morny.core.bot.api.messages.ErrorMessage
+import cc.sukazyo.cono.morny.util.hytrans.LangTag
+import com.pengrad.telegrambot.model.User
 
-/** Bot extensions for Morny feature.
-  */
-object BotExtension {
+object BotExtension extends BotExtension
+
+/** Bot extensions for Morny feature. */
+trait BotExtension {
 	
 	extension (errorMessage: ErrorMessage[?, ?]) {
 		
@@ -21,4 +24,13 @@ object BotExtension {
 		
 	}
 	
+	extension (user: User) {
+		
+		def prefer_language: String =
+			user.languageCode match
+				case null => ""
+				case x => LangTag.normalizeLangTag(x)
+		
+	}
+	
 }

src/main/scala/cc/sukazyo/cono/morny/core/bot/command/MornyInfoOnStart.scala

@@ -2,35 +2,30 @@ package cc.sukazyo.cono.morny.core.bot.command
 
 import cc.sukazyo.cono.morny.core.MornyCoeur
 import cc.sukazyo.cono.morny.core.bot.api.{ICommandAlias, ISimpleCommand}
-import cc.sukazyo.cono.morny.data.MornyInformation.{getAboutPic, getMornyAboutLinksHTML}
+import cc.sukazyo.cono.morny.data.MornyInformation.{getAboutPic, getMornyAboutLinksVars}
 import cc.sukazyo.cono.morny.util.tgapi.InputCommand
 import cc.sukazyo.cono.morny.util.tgapi.TelegramExtensions.Requests.unsafeExecute
 import com.pengrad.telegrambot.model.Update
 import com.pengrad.telegrambot.model.request.ParseMode
 import com.pengrad.telegrambot.request.SendPhoto
-import com.pengrad.telegrambot.TelegramBot
 
 class MornyInfoOnStart (using coeur: MornyCoeur) extends ISimpleCommand {
-	private given TelegramBot = coeur.account
+	import coeur.dsl.{*, given}
 	
 	override val name: String = "start"
 	override val aliases: List[ICommandAlias] = Nil
 	
 	override def execute (using command: InputCommand, event: Update): Unit = {
 		
+		given lang: String = event.message.from.prefer_language
 		SendPhoto(
 			event.message.chat.id,
 			getAboutPic
 		).caption(
-			s"""欢迎使用 <b>Morny Cono</b>，<i>来自安妮的侍从小鼠</i>。
-			   |Morny 具有各种各样的功能。
-			   |
-			   |————————————————
-			   |$getMornyAboutLinksHTML
-			   |————————————————
-			   |
-			   |（你可以随时通过 /info 重新获得这些信息）"""
-			.stripMargin
+			translations.trans(
+				"morny.command.info.sub_start.message",
+				translations.transAsVar("morny.information.about_links", getMornyAboutLinksVars*)
+			).stripMargin
 		).parseMode(ParseMode HTML)
 			.unsafeExecute
 		

src/main/scala/cc/sukazyo/cono/morny/core/bot/command/MornyInformation.scala

@@ -3,7 +3,6 @@ package cc.sukazyo.cono.morny.core.bot.command
 import cc.sukazyo.cono.morny.core.{MornyCoeur, MornySystem}
 import cc.sukazyo.cono.morny.core.bot.api.{ICommandAlias, ITelegramCommand}
 import cc.sukazyo.cono.morny.core.bot.api.messages.{ErrorMessage, MessagingContext}
-import cc.sukazyo.cono.morny.core.Log.logger
 import cc.sukazyo.cono.morny.data.MornyInformation.*
 import cc.sukazyo.cono.morny.data.TelegramStickers
 import cc.sukazyo.cono.morny.reporter.MornyReport
@@ -16,11 +15,11 @@ import cc.sukazyo.cono.morny.util.var_text.VarText
 import com.pengrad.telegrambot.model.Update
 import com.pengrad.telegrambot.model.request.ParseMode
 import com.pengrad.telegrambot.request.{SendMessage, SendPhoto, SendSticker}
-import com.pengrad.telegrambot.TelegramBot
 
 import java.lang.System
+
 class MornyInformation (using coeur: MornyCoeur) extends ITelegramCommand {
-	private given TelegramBot = coeur.account
+	import coeur.dsl.{*, given}
 	
 	private case object Subs {
 		val STICKERS = "stickers"
@@ -76,19 +75,10 @@ class MornyInformation (using coeur: MornyCoeur) extends ITelegramCommand {
 			cxt.bind_chat.id,
 			getAboutPic
 		).caption(
-			// language=html
-			(VarText(
-				"""<b>Morny Cono</b>
-				  |来自安妮的侍从小鼠。
-				  |————————————————
-				  |{about_links}""".stripMargin
-			).render(
-				"about_links" -> getMornyAboutLinksHTML
-			) :: Nil)
-				.map( f =>
-					logger `trace` f
-					f
-				).head
+			translations.trans(
+				"morny.command.info.message.about",
+				translations.transAsVar("morny.information.about_links", getMornyAboutLinksVars*)(using cxt.bind_message.from.prefer_language)
+			)(using cxt.bind_message.from.prefer_language)
 		).parseMode(ParseMode HTML).replyToMessageId(cxt.bind_message.messageId)
 			.unsafeExecute
 		

src/main/scala/cc/sukazyo/cono/morny/data/MornyInformation.scala

@@ -1,7 +1,7 @@
 package cc.sukazyo.cono.morny.data
 
 import cc.sukazyo.cono.morny.core.{MornyAbout, MornySystem}
-import cc.sukazyo.cono.morny.util.var_text.VarText
+import cc.sukazyo.cono.morny.util.var_text.Var
 
 import java.net.InetAddress
 import java.rmi.UnknownHostException
@@ -39,13 +39,8 @@ object MornyInformation {
 	
 	def getAboutPic: Array[Byte] = TelegramImages.IMG_ABOUT get
 	
-	def getMornyAboutLinksHTML: String =
-		VarText(
-			// language=html
-			"""<a href='{MORNY_SOURCECODE_LINK}'>source code</a> | <a href='{MORNY_SOURCECODE_SELF_HOSTED_MIRROR_LINK}'>backup</a>
-			  |<a href='{MORNY_ISSUE_TRACKER_LINK}'>反馈 / issue tracker</a>
-			  |<a href='{MORNY_USER_GUIDE_LINK}'>使用说明书 / user guide & docs</a>""".stripMargin
-		).render(
+	def getMornyAboutLinksVars: List[Var] =
+		List(
 			"MORNY_SOURCECODE_LINK" -> MornyAbout.MORNY_SOURCECODE_LINK,
 			"MORNY_SOURCECODE_SELF_HOSTED_MIRROR_LINK" -> MornyAbout.MORNY_SOURCECODE_SELF_HOSTED_MIRROR_LINK,
 			"MORNY_ISSUE_TRACKER_LINK" -> MornyAbout.MORNY_ISSUE_TRACKER_LINK,

src/main/scala/cc/sukazyo/cono/morny/morny_misc/Testing.scala

@@ -3,29 +3,26 @@ package cc.sukazyo.cono.morny.morny_misc
 import cc.sukazyo.cono.morny.core.MornyCoeur
 import cc.sukazyo.cono.morny.core.bot.api.{ICommandAlias, ISimpleCommand}
 import cc.sukazyo.cono.morny.core.bot.api.messages.{ErrorMessage, MessagingContext}
-import cc.sukazyo.cono.morny.core.bot.api.BotExtension.submit
 import cc.sukazyo.cono.morny.data.TelegramStickers
 import cc.sukazyo.cono.morny.util.tgapi.InputCommand
 import cc.sukazyo.cono.morny.util.tgapi.TelegramExtensions.Requests.unsafeExecute
 import com.pengrad.telegrambot.model.{Message, Update}
 import com.pengrad.telegrambot.model.request.ParseMode
 import com.pengrad.telegrambot.request.{SendMessage, SendSticker}
-import com.pengrad.telegrambot.TelegramBot
 
 class Testing (using coeur: MornyCoeur) extends ISimpleCommand {
-	private given TelegramBot = coeur.account
+	import coeur.dsl.{*, given}
 	
 	override val name: String = "test"
 	override val aliases: List[ICommandAlias] = Nil
 	
 	override def execute (using command: InputCommand, event: Update): Unit = {
 		given context: MessagingContext.WithUserAndMessage = MessagingContext.extract(using event.message)
+		given lang: String = context.bind_user.prefer_language
 		
 		SendMessage(
 			event.message.chat.id,
-			// language=html
-			"<b>Just</b> a TEST command.\n"
-				+ "Please input something to test the command."
+			translations.trans("morny.misc.command_test.message")
 		).replyToMessageId(event.message.messageId).parseMode(ParseMode HTML)
 			.unsafeExecute
 		
@@ -34,11 +31,13 @@ class Testing (using coeur: MornyCoeur) extends ISimpleCommand {
 	}
 	
 	private def execute2 (message: Message, previousContext: MessagingContext.WithUserAndMessage): Unit = {
+		given context: MessagingContext.WithUserAndMessage = MessagingContext.extract(using message)
+		given lang: String = context.bind_user.prefer_language
 		
 		if (message.text == "oops")
 			SendMessage(
 				message.chat.id,
-				"A test error message will be generated."
+				translations.trans("morny.misc.command_test.branch_oops.err_message_simple")
 			).replyToMessageId(message.messageId)
 				.unsafeExecute
 			ErrorMessage(
@@ -48,16 +47,17 @@ class Testing (using coeur: MornyCoeur) extends ISimpleCommand {
 				).replyToMessageId(message.messageId),
 				_complex = SendMessage(
 					message.chat.id,
-					"Oops: There is just a test error."
+					translations.trans("morny.misc.command_test.branch_oops.err_message_complex")
 				).replyToMessageId(message.messageId)
-			)(using MessagingContext.extract(using message))
-				.submit
+			).submit
 			return;
 		
 		SendMessage(
 			message.chat.id,
-			// language=html
-			"<b><u>Test command with following input:</u></b>\n" + message.text
+			translations.trans(
+				"morny.misc.command_test.branch_normal.message",
+				"replied_message" -> message.text
+			)
 		).replyToMessageId(message.messageId).parseMode(ParseMode HTML)
 			.unsafeExecute
 		

src/main/scala/cc/sukazyo/cono/morny/util/hytrans/Parser.scala

@@ -24,6 +24,7 @@ object Parser {
 				case Some(' ') | Some('\t') | None => // empty lines, will be ignored
 				case Some('#') => // comment line, will be ignored
 				case Some('%') => // document meta definition line, currently not supported
+				case Some('&') => // document meta definition line, currently not supported
 				case Some('|') => // content line
 					addLine(line drop 2)
 				case Some(_) => // a key definition line

src/main/scala/cc/sukazyo/cono/morny/util/hytrans/Translations.scala

@@ -1,6 +1,7 @@
 package cc.sukazyo.cono.morny.util.hytrans
 
 import cc.sukazyo.cono.morny.util.var_text.{Var, VarText}
+import cc.sukazyo.cono.morny.util.var_text.Var.String_As_VarText
 
 import scala.util.boundary
 
@@ -42,4 +43,7 @@ class Translations (
 	def trans (key: String, args: Var*)(using lang: String): String =
 		trans(key).render(args*)
 	
+	def transAsVar (key: String, args: Var*)(using lang: String): Var =
+		trans(key, args*).asVar(key)
+	
 }

src/main/scala/cc/sukazyo/cono/morny/util/var_text/Var.scala

@@ -8,7 +8,7 @@ import scala.language.implicitConversions
   *
   * You can just call the [[Var]] constructor to create a new Var, or use the implicit
   * conversion to create a var from a tuple of ([[String]], [[String]]), or use the extension
-  * method [[Var.StringAsVarText.asVar]] to convert a [[String]] to a var.
+  * method [[Var.String_As_VarText.asVar]] to convert a [[String]] to a var.
   * 
   * @since 2.0.0
   *
@@ -77,11 +77,11 @@ object Var {
 	  * 
 	  * @since 2.0.0
 	  */
-	implicit def StrStrTupleAsVar (tuple: (String, Any)): Var =
+	implicit def StrStrTuple_as_Var (tuple: (String, Any)): Var =
 		Var(tuple._1, tuple._2.toString)
 	
 	/** @see [[asVar]] */
-	implicit class StringAsVarText (text: String):
+	implicit class String_As_VarText (text: String):
 		/** Convert this string text to a [[Var]].
 		  * @since 2.0.0
 		  * @param id the var-id.

src/main/scala/cc/sukazyo/cono/morny/util/var_text/VarText.scala

@@ -2,6 +2,8 @@ package cc.sukazyo.cono.morny.util.var_text
 
 import cc.sukazyo.cono.morny.util.var_text.Var.isLegalId
 
+import scala.language.implicitConversions
+
 /** A text/string template that may contains some named replaceable variables. It's concept may
   * be similar with scala's `StringContext` or `GString` in groovy.
   *
@@ -56,6 +58,9 @@ object VarText {
 	def apply (_nodes: VTNode*): VarText = new VarText:
 		override val nodes: List[VTNode] = _nodes.toList
 	
+	implicit def VarText_is_String (varText: VarText): String =
+		varText.render()
+	
 	private val symbol_escape = '/'
 	private val symbol_var_start = '{'
 	private val symbol_var_end = '}'