From cce6591f54f29f6c4997a13a6138925bd5712762 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=A9a=20Saviot?= <lea.saviot@numworks.com>
Date: Tue, 6 Nov 2018 10:49:57 +0100
Subject: [PATCH] [apps] When editing an expression model, replace UnknownX
 with 'x'

---
 .../storage_expression_model_list_controller.cpp       | 10 +++++++++-
 poincare/include/poincare/symbol.h                     |  1 +
 poincare/src/symbol.cpp                                |  2 +-
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/apps/shared/storage_expression_model_list_controller.cpp b/apps/shared/storage_expression_model_list_controller.cpp
index 9366f0f58..020f5ac43 100644
--- a/apps/shared/storage_expression_model_list_controller.cpp
+++ b/apps/shared/storage_expression_model_list_controller.cpp
@@ -1,4 +1,5 @@
 #include "storage_expression_model_list_controller.h"
+#include <poincare/symbol.h>
 
 namespace Shared {
 
@@ -183,9 +184,16 @@ void StorageExpressionModelListController::editExpression(Ion::Events::Event eve
   char initialTextContent[TextField::maxBufferSize()];
   if (event == Ion::Events::OK || event == Ion::Events::EXE) {
     Ion::Storage::Record record = modelStore()->recordAtIndex(modelIndexForRow(selectedRow()));
-    ExpiringPointer<StorageExpressionModel> model =  modelStore()->modelForRecord(record);
+    ExpiringPointer<StorageExpressionModel> model = modelStore()->modelForRecord(record);
     model->text(initialTextContent, TextField::maxBufferSize());
     initialText = initialTextContent;
+    // Replace Poincare::Symbol::SpecialSymbols::UnknownX with 'x'
+    size_t initialTextLength = strlen(initialText);
+    for (size_t i = 0; i < initialTextLength; i++) {
+      if (initialTextContent[i] == Poincare::Symbol::SpecialSymbols::UnknownX) {
+        initialTextContent[i] = Poincare::Symbol::k_unknownXReadableChar;
+      }
+    }
   }
   inputController()->edit(this, event, this, initialText,
       [](void * context, void * sender){
diff --git a/poincare/include/poincare/symbol.h b/poincare/include/poincare/symbol.h
index 07f7389ae..77b1eff52 100644
--- a/poincare/include/poincare/symbol.h
+++ b/poincare/include/poincare/symbol.h
@@ -48,6 +48,7 @@ class Symbol final : public SymbolAbstract {
   friend class Store;
 public:
   static constexpr char k_ans[] = "ans";
+  static constexpr char k_unknownXReadableChar = 'x';
   enum SpecialSymbols : char {
     /* We can use characters from 1 to 31 as they do not correspond to usual
      * characters but events as 'end of text', 'backspace'... */
diff --git a/poincare/src/symbol.cpp b/poincare/src/symbol.cpp
index 9a6e74913..19c340e6e 100644
--- a/poincare/src/symbol.cpp
+++ b/poincare/src/symbol.cpp
@@ -75,7 +75,7 @@ float SymbolNode::characteristicXRange(Context & context, Preferences::AngleUnit
 Layout SymbolNode::createLayout(Preferences::PrintFloatMode floatDisplayMode, int numberOfSignificantDigits) const {
   if (m_name[0] == Symbol::SpecialSymbols::UnknownX) {
     assert(m_name[1] == 0);
-    return CharLayout('x');
+    return CharLayout(Symbol::k_unknownXReadableChar);
   }
   if (strcmp(m_name, "u(n)") == 0) {
     return HorizontalLayout(