Migrate power operator evaluator to Kotlin

src/main/kotlin/io/smnp/data/enumeration/DataType.kt

@@ -22,6 +22,10 @@ enum class DataType(val kotlinType: KClass<out Any>?) {
         return kotlinType.isInstance(value)
     }
 
+    fun isNumeric(): Boolean {
+        return this == INT || this == FLOAT
+    }
+
     override fun toString(): String {
         return super.toString().toLowerCase()
     }

src/main/kotlin/io/smnp/dsl/ast/model/node/BinaryOperatorAbstractNode.kt

@@ -1,6 +1,10 @@
 package io.smnp.dsl.ast.model.node
 
 abstract class BinaryOperatorAbstractNode(lhs: Node, operator: Node, rhs: Node) : Node(3, operator.position) {
+    operator fun component1() = children[0]
+    operator fun component2() = children[1]
+    operator fun component3() = children[2]
+
     val lhs: Node
     get() = children[0]
 

src/main/kotlin/io/smnp/evaluation/evaluator/DefaultEvaluator.kt

@@ -18,7 +18,8 @@ class DefaultEvaluator : Evaluator() {
             MapEvaluator(), 
 
             MinusOperatorEvaluator(), 
-            NotOperatorEvaluator()
+            NotOperatorEvaluator(),
+            PowerOperatorEvaluator()
         ).evaluate(node, environment)
     }
 }

src/main/kotlin/io/smnp/evaluation/evaluator/PowerOperatorEvaluator.kt

@@ -0,0 +1,26 @@
+package io.smnp.evaluation.evaluator
+
+import io.smnp.data.model.Value
+import io.smnp.dsl.ast.model.node.Node
+import io.smnp.dsl.ast.model.node.PowerOperatorNode
+import io.smnp.error.EvaluationException
+import io.smnp.evaluation.environment.Environment
+import io.smnp.evaluation.model.entity.EvaluatorOutput
+import kotlin.math.pow
+
+class PowerOperatorEvaluator : Evaluator() {
+    override fun supportedNodes() = listOf(PowerOperatorNode::class)
+
+    override fun tryToEvaluate(node: Node, environment: Environment): EvaluatorOutput {
+        val (lhsNode, _, rhsNode) = (node as PowerOperatorNode)
+        val evaluator = DefaultEvaluator()
+        val lhs = evaluator.evaluate(lhsNode, environment).value!!
+        val rhs = evaluator.evaluate(rhsNode, environment).value!!
+
+        if(!lhs.type.isNumeric() || !rhs.type.isNumeric()) {
+            throw EvaluationException("Operator ** supports only numeric types", node.position)
+        }
+
+        return EvaluatorOutput.value(Value.float((lhs.value as Number).toFloat().pow((rhs.value as Number).toFloat())))
+    }
+}