diff --git a/poincare/include/poincare/expression.h b/poincare/include/poincare/expression.h
index 912bdf1a4..e5a48e375 100644
--- a/poincare/include/poincare/expression.h
+++ b/poincare/include/poincare/expression.h
@@ -15,62 +15,62 @@ class Evaluation;
 class Expression {
 public:
   enum class Type : uint8_t {
-    Integer = 0,
-    Complex,
-    Symbol,
-    Parenthesis,
-    Opposite,
+    AbsoluteValue = 0,
     Addition,
-    Subtraction,
-    Multiplication,
-    Division,
-    Power,
-    Sum,
-    Product,
-    DivisionQuotient,
-    DivisionRemainder,
-    GreatCommonDivisor,
-    LeastCommonMultiple,
-    Floor,
-    Ceiling,
-    Round,
-    FracPart,
-    AbsoluteValue,
-    Factorial,
-    ImaginaryPart,
-    RealPart,
-    ComplexArgument,
-    Conjugate,
-    Logarithm,
-    NaperianLogarithm,
-    SquareRoot,
-    NthRoot,
-    Cosine,
-    Sine,
-    Tangent,
     ArcCosine,
     ArcSine,
     ArcTangent,
-    HyperbolicCosine,
-    HyperbolicSine,
-    HyperbolicTangent,
+    BinomialCoefficient,
+    Ceiling,
+    Complex,
+    ComplexArgument,
+    ComplexMatrix,
+    ConfidenceInterval,
+    Conjugate,
+    Cosine,
+    Derivative,
+    Determinant,
+    Division,
+    DivisionQuotient,
+    DivisionRemainder,
+    ExpressionMatrix,
+    Factorial,
+    Floor,
+    FracPart,
+    GreatCommonDivisor,
     HyperbolicArcCosine,
     HyperbolicArcSine,
     HyperbolicArcTangent,
-    Derivative,
+    HyperbolicCosine,
+    HyperbolicSine,
+    HyperbolicTangent,
+    ImaginaryPart,
+    Integer,
     Integral,
-    BinomialCoefficient,
-    PermuteCoefficient,
-    ConfidenceInterval,
-    PredictionInterval,
-    ExpressionMatrix,
-    ComplexMatrix,
+    LeastCommonMultiple,
+    Logarithm,
     MatrixDimension,
     MatrixInverse,
     MatrixTrace,
     MatrixTranspose,
-    Determinant,
+    Multiplication,
+    NaperianLogarithm,
+    NthRoot,
+    Opposite,
+    Parenthesis,
+    PermuteCoefficient,
+    Power,
+    PredictionInterval,
+    Product,
+    RealPart,
+    Round,
+    Sine,
+    SquareRoot,
     Store,
+    Subtraction,
+    Sum,
+    Symbol,
+    Tangent,
     Undefined = 255
   };
   enum class FloatDisplayMode {
diff --git a/poincare/src/simplification/rulegen/node.cpp b/poincare/src/simplification/rulegen/node.cpp
index 444387de2..194fb030b 100644
--- a/poincare/src/simplification/rulegen/node.cpp
+++ b/poincare/src/simplification/rulegen/node.cpp
@@ -26,6 +26,7 @@ void Node::identifyAnonymousChildren(int * index) {
 // Generation
 
 void Node::generateSelector(Rule * rule) {
+  sort();
   int i = 0;
 
   for (Node * child : *m_children) {
@@ -110,6 +111,93 @@ int Node::intValue() const {
   return result;
 }
 
+int Node::compareTo(Node * n) const {
+  if (m_name->compare("Any")) {
+    if (n->m_name->compare("Any")) {
+      if (identifier().compare(n->identifier()) == 0) {
+        return 0;
+      } else if (identifier().compare(n->identifier()) > 0) {
+        return 1;
+      } else {
+        return -1;
+      }
+    } else if (n->m_name->compare("SameAs")) {
+      if (identifier().compare(n->value()) == 0) {
+        return -1;
+      } else if (identifier().compare(n->value()) > 0) {
+        return 1;
+      } else {
+        return -1;
+      }
+    } else {
+      return 1;
+    }
+  } else if (m_name->compare("SameAs")) {
+    if (n->m_name->compare("Any")) {
+      if (value().compare(n->identifier()) == 0) {
+        return 1;
+      } else if (value().compare(n->identifier()) > 0) {
+        return 1;
+      } else {
+        return -1;
+      }
+    } else if (n->m_name->compare("SameAs")) {
+      if (value().compare(n->value()) == 0) {
+        return 0;
+      } else if (value().compare(n->value()) > 0) {
+        return 1;
+      } else {
+        return -1;
+      }
+    } else {
+      return 1;
+    }
+  } else {
+    if (n->m_name->compare("Any")) {
+      return -1;
+    } else if (n->m_name->compare("SameAs")) {
+      return -1;
+    } else {
+      if (name().compare(n->name()) != 0) {
+        if (name().compare(n->name()) > 0) {
+          return 1;
+        } else {
+          return -1;
+        }
+      } else {
+        if (intValue() == n->intValue()) {
+         return 0;
+        } else if (intValue() > n->intValue()) {
+          return 1;
+        } else {
+          return -1;
+        }
+      }
+    }
+  }
+}
+
+void Node::sort() {
+  if (m_children->size() == 0) {
+    return;
+  }
+  for (Node * child : *m_children) {
+    child->sort();
+  }
+  for (int i = m_children->size()-1; i > 0; i--) {
+    bool isSorted = true;
+    for (int j = 0; j < m_children->size()-1; j++) {
+      if (m_children->at(j)->compareTo(m_children->at(j+1)) > 0) {
+        std::swap(m_children->at(j), m_children->at(j+1));
+        isSorted = false;
+      }
+    }
+    if (isSorted) {
+      return;
+    }
+  }
+}
+
 #if 0
 
 std::string Node::generateSelectorConstructor(Rule * context) {
diff --git a/poincare/src/simplification/rulegen/node.h b/poincare/src/simplification/rulegen/node.h
index f21e96697..aa2e1e0d7 100644
--- a/poincare/src/simplification/rulegen/node.h
+++ b/poincare/src/simplification/rulegen/node.h
@@ -24,6 +24,8 @@ public:
   std::string value() const;
   int intValue() const;
   int numberOfChildren() { return m_children->size(); }
+  int compareTo(Node * node) const;
+  void sort();
 private:
   int selectorCaptureIndexInRule(Rule * rule);
   int selectorIndexInRule(Rule * rule);