[apps/poincare] use Symbol::k_ans constexpr char *

apps/calculation/app.cpp

@@ -3,6 +3,7 @@
 #include "../shared/poincare_helpers.h"
 #include "calculation_icon.h"
 #include "../i18n.h"
+#include <poincare/symbol.h>
 
 using namespace Poincare;
 
@@ -95,7 +96,7 @@ bool App::textInputIsCorrect(const char * text) {
     return false;
   }
   Expression ansExpression = static_cast<Snapshot *>(snapshot())->calculationStore()->ansExpression(localContext());
-  exp = exp.replaceSymbolWithExpression("ans", ansExpression);
+  exp = exp.replaceSymbolWithExpression(Symbol::k_ans, ansExpression);
   char buffer[Calculation::k_printedExpressionSize];
   int length = PoincareHelpers::Serialize(exp, buffer, sizeof(buffer));
   /* if the buffer is totally full, it is VERY likely that writeTextInBuffer

apps/calculation/calculation.cpp

@@ -1,6 +1,7 @@
 #include "calculation.h"
 #include "calculation_store.h"
 #include "../shared/poincare_helpers.h"
+#include <poincare/symbol.h>
 #include <string.h>
 #include <cmath>
 #include <poincare/symbol.h>
@@ -34,7 +35,7 @@ void Calculation::reset() {
 
 void Calculation::setContent(const char * c, Context * context, Expression ansExpression) {
   reset();
-  Expression input = Expression::parse(c).replaceSymbolWithExpression("ans", ansExpression);
+  Expression input = Expression::parse(c).replaceSymbolWithExpression(Symbol::k_ans, ansExpression);
   /* We do not store directly the text enter by the user because we do not want
    * to keep Ans symbol in the calculation store. */
   PoincareHelpers::Serialize(input, m_inputText, sizeof(m_inputText));

apps/calculation/expression_field.cpp

@@ -1,4 +1,5 @@
 #include "expression_field.h"
+#include <poincare/symbol.h>
 
 namespace Calculation {
 
@@ -7,7 +8,7 @@ bool ExpressionField::handleEvent(Ion::Events::Event event) {
     return false;
   }
   if (event == Ion::Events::Ans) {
-    handleEventWithText("ans");
+    handleEventWithText(Poincare::Symbol::k_ans);
     return true;
   }
   if (isEditing() && isEmpty() &&
@@ -17,7 +18,7 @@ bool ExpressionField::handleEvent(Ion::Events::Event event) {
        event == Ion::Events::Square ||
        event == Ion::Events::Division ||
        event == Ion::Events::Sto)) {
-    handleEventWithText("ans");
+    handleEventWithText(Poincare::Symbol::k_ans);
   }
   return(::ExpressionField::handleEvent(event));
 }

poincare/include/poincare/symbol.h

@@ -65,6 +65,7 @@ class Symbol final : public Expression {
   friend class Expression;
   friend class Store;
 public:
+  static constexpr char k_ans[] = "ans";
   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'... */

poincare/src/expression_parser.y

@@ -154,7 +154,7 @@ exp    : pow              { $$ = $1; }
        ;
 
 final_exp : exp           { $$ = $1; }
-          | exp STO symb  { if (static_cast<Symbol&>($3).name() == Symbol::SpecialSymbols::Ans) { YYERROR; } ; $$ = Store($1, static_cast<Symbol &>($3)); }
+          | exp STO symb  { if (static_cast<Symbol&>($3).name() == Symbol::k_ans) { YYERROR; } ; $$ = Store($1, static_cast<Symbol &>($3)); }
           | exp EQUAL exp { $$ = Equal($1, $3); }
           ;
 %%