[escher] TextField: when handling event with text, replace system

parenthesis by user parenthesis to switch from layout structure to
linear text.

When copying a layout and pasting it to a textfield, we add required
parentheses:

 2+1
----- serializes to ---> [2+1]/3 and is turned to (2+1)/3 before being
  3
handled by a textfield.

escher/src/text_field.cpp

@@ -3,6 +3,7 @@
 #include <escher/clipboard.h>
 #include <ion/unicode/utf8_decoder.h>
 #include <ion/unicode/utf8_helper.h>
+#include <poincare/serialization_helper.h>
 #include <assert.h>
 
 static inline int minInt(int x, int y) { return x < y ? x : y; }
@@ -462,6 +463,9 @@ bool TextField::handleEventWithText(const char * eventText, bool indentation, bo
   char buffer[bufferSize];
   UTF8Helper::CopyAndRemoveCodePoint(buffer, bufferSize, eventText, UCodePointEmpty);
 
+  // Replace System parentheses (used to keep layout tree structure) by normal parentheses
+  Poincare::SerializationHelper::ReplaceSystemParenthesesByUserParentheses(buffer);
+
   const char * nextCursorLocation = m_contentView.draftTextBuffer() + draftTextLength();
   if (insertTextAtLocation(buffer, cursorLocation())) {
     /* The cursor position depends on the text as we sometimes want to position

poincare/include/poincare/serialization_helper.h

@@ -13,6 +13,9 @@ namespace Poincare {
  */
 
 namespace SerializationHelper {
+
+  void ReplaceSystemParenthesesByUserParentheses(char * buffer);
+
   // SerializableReference to text
   int Infix(
       const TreeNode * node,

poincare/src/serialization_helper.cpp

@@ -1,10 +1,30 @@
 #include <poincare/serialization_helper.h>
 #include <ion/unicode/utf8_decoder.h>
+#include <ion/unicode/utf8_helper.h>
 #include <string.h>
 #include <assert.h>
 
 namespace Poincare {
 
+void replaceOneCharSizedCodePointWith(char * buffer, CodePoint searchedCodePoint, CodePoint newCodePoint) {
+  assert(UTF8Decoder::CharSizeOfCodePoint(searchedCodePoint == 1));
+  assert(UTF8Decoder::CharSizeOfCodePoint(newCodePoint == 1));
+  UTF8Helper::PerformAtCodePoints(
+      buffer,
+      searchedCodePoint,
+      [](int codePointOffset, void * text, int newCodePoint, int bufferLength) {
+        *((char *)text+codePointOffset) = (char)newCodePoint;
+      },
+      [](int c1, void * c2, int c3, int c4) {},
+      (void *)buffer,
+      newCodePoint);
+}
+
+void SerializationHelper::ReplaceSystemParenthesesByUserParentheses(char * buffer) {
+  replaceOneCharSizedCodePointWith(buffer, UCodePointLeftSystemParenthesis, '(');
+  replaceOneCharSizedCodePointWith(buffer, UCodePointRightSystemParenthesis, ')');
+}
+
 static bool checkBufferSize(char * buffer, int bufferSize, int * result) {
   // If buffer has size 0 or 1, put a zero if it fits and return
   if (bufferSize == 0) {