From 8f03d672ce4d799d00ea5b9eb7b29025e9335f8d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=89milie=20Feral?= <emilie.feral@numworks.com>
Date: Fri, 6 Oct 2017 18:14:46 +0200
Subject: [PATCH] [poincare] Implement Subtraction::simplify

Change-Id: If6494c80c3c2c2132fb3f584c720f7b978917a8c
---
 poincare/include/poincare/subtraction.h |  2 ++
 poincare/src/subtraction.cpp            | 14 ++++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/poincare/include/poincare/subtraction.h b/poincare/include/poincare/subtraction.h
index 34659ac55..79ee0f1cc 100644
--- a/poincare/include/poincare/subtraction.h
+++ b/poincare/include/poincare/subtraction.h
@@ -13,6 +13,8 @@ public:
   Type type() const override;
   Expression * clone() const override;
   template<typename T> static Complex<T> compute(const Complex<T> c, const Complex<T> d);
+  /* Simplification */
+  void immediateSimplify() override;
 private:
   template<typename T> static Evaluation<T> * computeOnMatrixAndComplex(Evaluation<T> * m, const Complex<T> * c) {
     return EvaluationEngine::elementWiseOnComplexAndComplexMatrix(c, m, compute<T>);
diff --git a/poincare/src/subtraction.cpp b/poincare/src/subtraction.cpp
index e499759ef..3c5c779f0 100644
--- a/poincare/src/subtraction.cpp
+++ b/poincare/src/subtraction.cpp
@@ -4,6 +4,9 @@ extern "C" {
 }
 
 #include <poincare/subtraction.h>
+#include <poincare/multiplication.h>
+#include <poincare/rational.h>
+#include <poincare/addition.h>
 #include <poincare/opposite.h>
 #include <poincare/complex_matrix.h>
 #include "layout/horizontal_layout.h"
@@ -25,6 +28,17 @@ Complex<T> Subtraction::compute(const Complex<T> c, const Complex<T> d) {
   return Complex<T>::Cartesian(c.a()-d.a(), c.b() - d.b());
 }
 
+void Subtraction::immediateSimplify() {
+  const Expression * multOperands[2] = {new Rational(Integer(-1)), operand(1)};
+  Multiplication * m = new Multiplication(multOperands, 2, false);
+  const Expression * addOperands[2] = {operand(0), m};
+  Addition * a = new Addition(addOperands, 2, false);
+  m->immediateSimplify();
+  detachOperands();
+  replaceWith(a, true);
+  a->immediateSimplify();
+}
+
 template<typename T> Evaluation<T> * Subtraction::computeOnComplexAndMatrix(const Complex<T> * c, Evaluation<T> * m) {
   Evaluation<T> * opposite = computeOnMatrixAndComplex(m, c);
   Complex<T> * operands = new Complex<T>[opposite->numberOfRows() * opposite->numberOfColumns()];