From 4ae72d68d8a511fdf4b3fef8d1970c3ec3cbc01e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=89milie=20Feral?= <emilie.feral@numworks.com>
Date: Fri, 10 Aug 2018 10:10:12 +0200
Subject: [PATCH] [poincare] Enable to call method on undefined Expression

---
 poincare/include/poincare.h                  | 1 +
 poincare/include/poincare/expression.h       | 2 +-
 poincare/include/poincare/layout_reference.h | 2 +-
 poincare/src/expression.cpp                  | 7 +++++--
 4 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/poincare/include/poincare.h b/poincare/include/poincare.h
index ddb662ac8..dca3a9b83 100644
--- a/poincare/include/poincare.h
+++ b/poincare/include/poincare.h
@@ -105,6 +105,7 @@
 #include <poincare/vertical_offset_layout_node.h>
 #else
 
+#include <poincare/global_context.h>
 #include <poincare/addition.h>
 #include <poincare/matrix_complex.h>
 #include <poincare/multiplication.h>
diff --git a/poincare/include/poincare/expression.h b/poincare/include/poincare/expression.h
index 970411635..2a20b7408 100644
--- a/poincare/include/poincare/expression.h
+++ b/poincare/include/poincare/expression.h
@@ -106,7 +106,7 @@ public:
   bool isEqualToItsApproximationLayout(Expression approximation, int bufferSize, Preferences::AngleUnit angleUnit, Preferences::PrintFloatMode floatDisplayMode, int numberOfSignificantDigits, Context & context);
 
   /* Layout Helper */
-  LayoutRef createLayout(Preferences::PrintFloatMode floatDisplayMode, int numberOfSignificantDigits) const { return this->node()->createLayout(floatDisplayMode, numberOfSignificantDigits); }
+  LayoutRef createLayout(Preferences::PrintFloatMode floatDisplayMode, int numberOfSignificantDigits) const { return isDefined() ? node()->createLayout(floatDisplayMode, numberOfSignificantDigits) : LayoutRef(); }
   int serialize(char * buffer, int bufferSize, Preferences::PrintFloatMode floatDisplayMode, int numberOfSignificantDigits = PrintFloat::k_numberOfStoredSignificantDigits) const { return this->node()->serialize(buffer, bufferSize, floatDisplayMode, numberOfSignificantDigits); }
 
   /* Simplification */
diff --git a/poincare/include/poincare/layout_reference.h b/poincare/include/poincare/layout_reference.h
index 54607da14..94dbd82e1 100644
--- a/poincare/include/poincare/layout_reference.h
+++ b/poincare/include/poincare/layout_reference.h
@@ -14,7 +14,7 @@ public:
   using TreeByReference::operator==;
   using TreeByReference::operator!=;
 
-  LayoutReference(LayoutNode * node) :
+  LayoutReference(LayoutNode * node = nullptr) :
     TreeByReference(node) {}
 
   LayoutReference clone() const {
diff --git a/poincare/src/expression.cpp b/poincare/src/expression.cpp
index 4cb5bab9c..e767760d3 100644
--- a/poincare/src/expression.cpp
+++ b/poincare/src/expression.cpp
@@ -220,8 +220,11 @@ Expression Expression::deepBeautify(Context & context, Preferences::AngleUnit an
 
 template<typename U>
 Expression Expression::approximate(Context& context, Preferences::AngleUnit angleUnit, Preferences::Preferences::ComplexFormat complexFormat) const {
-  Evaluation<U> e = node()->approximate(U(), context, angleUnit);
-  return e->complexToExpression(complexFormat);
+  if (isDefined()) {
+    Evaluation<U> e = node()->approximate(U(), context, angleUnit);
+    return e->complexToExpression(complexFormat);
+  }
+  return Undefined();
 }
 
 template<typename U>