EKT

src/main/kotlin/net/shadowfacts/ekt/EKT.kt

@@ -0,0 +1,74 @@
+package net.shadowfacts.ekt
+
+import java.io.File
+import javax.script.ScriptContext
+import javax.script.ScriptEngineManager
+
+/**
+ * @author shadowfacts
+ */
+object EKT {
+
+	private val startString = ":]"
+	private val endString = "[:"
+	private val startStringRegex = Regex("(?:^|[^\\\\])([:=])]\n?")
+	private val endStringRegex = Regex("\\[([:=])")
+
+	private val scriptPrefix = """
+val _result = StringBuilder()
+fun echo(s: Any) { _result.append(s) }
+"""
+	private val scriptSuffix = """
+_result.toString()
+"""
+
+	private val manager by lazy {
+		ScriptEngineManager()
+	}
+
+	fun render(template: String, data: Map<String, Any>): String {
+		@Suppress("NAME_SHADOWING")
+		var template = template
+		template = template.replace("\"", "\\\"")
+		template = startString + template + endString
+		template = template.replace(startStringRegex, {
+			var res = "\necho(\"\"\""
+			if (it.groups[1]!!.value == "=") res = ")" + res
+			res
+		})
+		template = template.replace(endStringRegex, {
+			var res = "\"\"\")\n"
+			if (it.groups[1]!!.value == "=") res += "echo("
+			res
+		})
+
+		val script = scriptPrefix + template + scriptSuffix
+
+		File("script.kts").apply {
+			if (!exists()) createNewFile()
+			writeText(script)
+		}
+
+		return eval(script, data) as String
+	}
+
+	fun render(template: File, data: Map<String, Any>): String {
+		return render(template.readText(), data)
+	}
+
+	internal fun eval(script: String, data: Map<String, Any> = mapOf()): Any? {
+		val engine = manager.getEngineByExtension("kts")
+		val bindings = engine.getBindings(ScriptContext.ENGINE_SCOPE)
+		bindings.putAll(data)
+
+//		Hack to allow data to be accessed by name from template instead of via bindings map
+		val unwrapBindings = data.keys.map {
+			val type = data[it]!!::class.qualifiedName
+			"val $it = bindings[\"$it\"] as $type;"
+		}.joinToString("\n")
+		engine.eval(unwrapBindings)
+
+		return engine.eval(script)
+	}
+
+}

src/main/resources/META-INF/services/javax.script.ScriptEngineFactory

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+org.jetbrains.kotlin.script.jsr223.KotlinJsr223JvmLocalScriptEngineFactory

src/test/kotlin/net/shadowfacts/ekt/Test.kt

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+package net.shadowfacts.ekt
+
+import java.io.File
+
+/**
+ * @author shadowfacts
+ */
+fun main(args: Array<String>) {
+	val res = EKT.render(File("template.ekt"), mapOf(
+			"value" to 11
+	))
+
+	File("result.txt").apply {
+		if (!exists()) createNewFile()
+		writeText(res)
+	}
+}