From c64a89c6b6296517d7c7b9690e7ae319ae54fcd8 Mon Sep 17 00:00:00 2001
From: Iaroslav <postovalovya@gmail.com>
Date: Mon, 27 Jul 2020 19:27:59 +0700
Subject: [PATCH] Implement power as binary operation with unchecked cast, add
 tests on parser precedence

---
 .../kotlin/scientifik/kmath/ast/MST.kt        |  8 ++---
 .../kmath/ast/ParserPrecedenceTest.kt         | 36 +++++++++++++++++++
 .../kmath/operations/NumberAlgebra.kt         | 11 ++++--
 3 files changed, 48 insertions(+), 7 deletions(-)
 create mode 100644 kmath-ast/src/jvmTest/kotlin/scietifik/kmath/ast/ParserPrecedenceTest.kt

diff --git a/kmath-ast/src/commonMain/kotlin/scientifik/kmath/ast/MST.kt b/kmath-ast/src/commonMain/kotlin/scientifik/kmath/ast/MST.kt
index e87df882f..1127c18aa 100644
--- a/kmath-ast/src/commonMain/kotlin/scientifik/kmath/ast/MST.kt
+++ b/kmath-ast/src/commonMain/kotlin/scientifik/kmath/ast/MST.kt
@@ -2,7 +2,6 @@ package scientifik.kmath.ast
 
 import scientifik.kmath.operations.Algebra
 import scientifik.kmath.operations.NumericAlgebra
-import scientifik.kmath.operations.RealField
 
 /**
  * A Mathematical Syntax Tree node for mathematical expressions
@@ -49,12 +48,11 @@ fun <T> Algebra<T>.evaluate(node: MST): T = when (node) {
     is MST.Binary -> when {
         this !is NumericAlgebra -> binaryOperation(node.operation, evaluate(node.left), evaluate(node.right))
         node.left is MST.Numeric && node.right is MST.Numeric -> {
-            val number = RealField.binaryOperation(
+            binaryOperation(
                 node.operation,
-                node.left.value.toDouble(),
-                node.right.value.toDouble()
+                number(node.left.value),
+                number(node.right.value)
             )
-            number(number)
         }
         node.left is MST.Numeric -> leftSideNumberOperation(node.operation, node.left.value, evaluate(node.right))
         node.right is MST.Numeric -> rightSideNumberOperation(node.operation, evaluate(node.left), node.right.value)
diff --git a/kmath-ast/src/jvmTest/kotlin/scietifik/kmath/ast/ParserPrecedenceTest.kt b/kmath-ast/src/jvmTest/kotlin/scietifik/kmath/ast/ParserPrecedenceTest.kt
new file mode 100644
index 000000000..9bdbb12c9
--- /dev/null
+++ b/kmath-ast/src/jvmTest/kotlin/scietifik/kmath/ast/ParserPrecedenceTest.kt
@@ -0,0 +1,36 @@
+package scietifik.kmath.ast
+
+import scientifik.kmath.ast.evaluate
+import scientifik.kmath.ast.parseMath
+import scientifik.kmath.operations.Field
+import scientifik.kmath.operations.RealField
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+internal class ParserPrecedenceTest {
+    private val f: Field<Double> = RealField
+
+    @Test
+    fun test1(): Unit = assertEquals(6.0, f.evaluate("2*2+2".parseMath()))
+
+    @Test
+    fun test2(): Unit = assertEquals(6.0, f.evaluate("2+2*2".parseMath()))
+
+    @Test
+    fun test3(): Unit = assertEquals(10.0, f.evaluate("2^3+2".parseMath()))
+
+    @Test
+    fun test4(): Unit = assertEquals(10.0, f.evaluate("2+2^3".parseMath()))
+
+    @Test
+    fun test5(): Unit = assertEquals(16.0, f.evaluate("2^3*2".parseMath()))
+
+    @Test
+    fun test6(): Unit = assertEquals(16.0, f.evaluate("2*2^3".parseMath()))
+
+    @Test
+    fun test7(): Unit = assertEquals(18.0, f.evaluate("2+2^3*2".parseMath()))
+
+    @Test
+    fun test8(): Unit = assertEquals(18.0, f.evaluate("2*2^3+2".parseMath()))
+}
diff --git a/kmath-core/src/commonMain/kotlin/scientifik/kmath/operations/NumberAlgebra.kt b/kmath-core/src/commonMain/kotlin/scientifik/kmath/operations/NumberAlgebra.kt
index 953c5a112..ca5fa68f0 100644
--- a/kmath-core/src/commonMain/kotlin/scientifik/kmath/operations/NumberAlgebra.kt
+++ b/kmath-core/src/commonMain/kotlin/scientifik/kmath/operations/NumberAlgebra.kt
@@ -34,6 +34,13 @@ interface ExtendedField<T> : ExtendedFieldOperations<T>, Field<T> {
     }
 }
 
+interface NumberExtendedField<T> : ExtendedField<T> {
+    override fun binaryOperation(operation: String, left: T, right: T): T = when (operation) {
+        PowerOperations.POW_OPERATION -> power(left, right as Number)
+        else -> super.binaryOperation(operation, left, right)
+    }
+}
+
 /**
  * Real field element wrapping double.
  *
@@ -53,7 +60,7 @@ inline class Real(val value: Double) : FieldElement<Double, Real, RealField> {
  * A field for double without boxing. Does not produce appropriate field element
  */
 @Suppress("EXTENSION_SHADOWED_BY_MEMBER", "OVERRIDE_BY_INLINE", "NOTHING_TO_INLINE")
-object RealField : ExtendedField<Double>, Norm<Double, Double> {
+object RealField : NumberExtendedField<Double>, Norm<Double, Double> {
     override val zero: Double = 0.0
     override inline fun add(a: Double, b: Double) = a + b
     override inline fun multiply(a: Double, b: Double) = a * b
@@ -88,7 +95,7 @@ object RealField : ExtendedField<Double>, Norm<Double, Double> {
 }
 
 @Suppress("EXTENSION_SHADOWED_BY_MEMBER", "OVERRIDE_BY_INLINE", "NOTHING_TO_INLINE")
-object FloatField : ExtendedField<Float>, Norm<Float, Float> {
+object FloatField : NumberExtendedField<Float>, Norm<Float, Float> {
     override val zero: Float = 0f
     override inline fun add(a: Float, b: Float) = a + b
     override inline fun multiply(a: Float, b: Float) = a * b