From a28a98080dab918fcd5293e10a578b7808f25aba Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bart=C5=82omiej=20Przemys=C5=82aw=20Pluta?=
 <noreply.git@mx.bartlomiejpluta.com>
Date: Sat, 7 Mar 2020 18:13:17 +0100
Subject: [PATCH] Migrate sum operator evaluator to Kotlin

---
 .../evaluation/evaluator/DefaultEvaluator.kt  |  3 +-
 .../evaluator/ProductOperatorEvaluator.kt     |  2 +-
 .../evaluator/SumOperatorEvaluator.kt         | 50 +++++++++++++++++++
 3 files changed, 53 insertions(+), 2 deletions(-)
 create mode 100644 src/main/kotlin/io/smnp/evaluation/evaluator/SumOperatorEvaluator.kt

diff --git a/src/main/kotlin/io/smnp/evaluation/evaluator/DefaultEvaluator.kt b/src/main/kotlin/io/smnp/evaluation/evaluator/DefaultEvaluator.kt
index 389991c..cf45b78 100644
--- a/src/main/kotlin/io/smnp/evaluation/evaluator/DefaultEvaluator.kt
+++ b/src/main/kotlin/io/smnp/evaluation/evaluator/DefaultEvaluator.kt
@@ -20,7 +20,8 @@ class DefaultEvaluator : Evaluator() {
             MinusOperatorEvaluator(), 
             NotOperatorEvaluator(),
             PowerOperatorEvaluator(),
-            ProductOperatorEvaluator()
+            ProductOperatorEvaluator(),
+            SumOperatorEvaluator()
         ).evaluate(node, environment)
     }
 }
\ No newline at end of file
diff --git a/src/main/kotlin/io/smnp/evaluation/evaluator/ProductOperatorEvaluator.kt b/src/main/kotlin/io/smnp/evaluation/evaluator/ProductOperatorEvaluator.kt
index 7756f05..c8db2d1 100644
--- a/src/main/kotlin/io/smnp/evaluation/evaluator/ProductOperatorEvaluator.kt
+++ b/src/main/kotlin/io/smnp/evaluation/evaluator/ProductOperatorEvaluator.kt
@@ -22,7 +22,7 @@ class ProductOperatorEvaluator : Evaluator() {
         val operator = (opNode as TokenNode).token.type
 
         if (!lhs.type.isNumeric() || !rhs.type.isNumeric()) {
-            throw EvaluationException("Operator $operator supports only numeric types", node.position)
+            throw EvaluationException("Operator ${operator.token} supports only numeric types", node.position)
         }
 
         return EvaluatorOutput.value(
diff --git a/src/main/kotlin/io/smnp/evaluation/evaluator/SumOperatorEvaluator.kt b/src/main/kotlin/io/smnp/evaluation/evaluator/SumOperatorEvaluator.kt
new file mode 100644
index 0000000..5eec676
--- /dev/null
+++ b/src/main/kotlin/io/smnp/evaluation/evaluator/SumOperatorEvaluator.kt
@@ -0,0 +1,50 @@
+package io.smnp.evaluation.evaluator
+
+import io.smnp.data.enumeration.DataType
+import io.smnp.data.model.Value
+import io.smnp.dsl.ast.model.node.Node
+import io.smnp.dsl.ast.model.node.SumOperatorNode
+import io.smnp.dsl.ast.model.node.TokenNode
+import io.smnp.dsl.token.model.enumeration.TokenType
+import io.smnp.error.EvaluationException
+import io.smnp.error.ShouldNeverReachThisLineException
+import io.smnp.evaluation.environment.Environment
+import io.smnp.evaluation.model.entity.EvaluatorOutput
+
+class SumOperatorEvaluator : Evaluator() {
+    override fun supportedNodes() = listOf(SumOperatorNode::class)
+
+    override fun tryToEvaluate(node: Node, environment: Environment): EvaluatorOutput {
+        val evaluator = DefaultEvaluator()
+        val (lhsNode, opNode, rhsNode) = (node as SumOperatorNode)
+        val lhs = evaluator.evaluate(lhsNode, environment).value!!
+        val rhs = evaluator.evaluate(rhsNode, environment).value!!
+        val operator = (opNode as TokenNode).token.type
+
+        if(!lhs.type.isNumeric() || !rhs.type.isNumeric()) {
+            throw EvaluationException("Operator ${operator.token} supports only numeric types", node.position)
+        }
+
+        return EvaluatorOutput.value(when(operator) {
+            TokenType.PLUS -> sum(lhs, rhs)
+            TokenType.MINUS -> difference(lhs, rhs)
+            else -> throw ShouldNeverReachThisLineException()
+        })
+    }
+
+    private fun sum(lhs: Value, rhs: Value): Value {
+        if(listOf(lhs.type, rhs.type).contains(DataType.FLOAT)) {
+            return Value.float((lhs.value as Number).toFloat() + (rhs.value as Number).toFloat())
+        }
+
+        return Value.int((lhs.value as Int) + (rhs.value as Int))
+    }
+
+    private fun difference(lhs: Value, rhs: Value): Value {
+        if(listOf(lhs.type, rhs.type).contains(DataType.FLOAT)) {
+            return Value.float((lhs.value as Number).toFloat() - (rhs.value as Number).toFloat())
+        }
+
+        return Value.int((lhs.value as Int) - (rhs.value as Int))
+    }
+}
\ No newline at end of file