[poincare] Move the xcontext to poincare to be used by derivative object

Change-Id: Ib950c7db7d864e0ff56c7964f4591bce180d627d

apps/graph/Makefile

@@ -13,7 +13,6 @@ app_objs += $(addprefix apps/graph/,\
   list/new_function_cell.o\
   list/list_controller.o\
   list/parameter_controller.o\
-  local_context.o\
   values/abscissa_parameter_controller.o\
   values/derivative_parameter_controller.o\
   values/function_parameter_controller.o\

apps/graph/app.cpp

@@ -6,7 +6,7 @@ namespace Graph {
 App::App(Container * container, Context * context) :
   TextFieldDelegateApp(container, &m_inputViewController, "Graph", ImageStore::GraphIcon),
   m_functionStore(FunctionStore()),
-  m_localContext(LocalContext(context)),
+  m_xContext(XContext(context)),
   m_listController(ListController(&m_listHeader, &m_functionStore, &m_listHeader)),
   m_listHeader(HeaderViewController(nullptr, &m_listController, &m_listController)),
   m_listStackViewController(StackViewController(&m_tabViewController, &m_listHeader)),
@@ -28,7 +28,7 @@ InputViewController * App::inputViewController() {
 }
 
 Context * App::localContext() {
-  return &m_localContext;
+  return &m_xContext;
 }
 
 }

apps/graph/app.h

@@ -2,8 +2,8 @@
 #define GRAPH_APP_H
 
 #include <escher.h>
+#include <poincare.h>
 #include "function_store.h"
-#include "local_context.h"
 #include "graph/graph_controller.h"
 #include "list/list_controller.h"
 #include "values/values_controller.h"
@@ -18,7 +18,7 @@ public:
   Context * localContext() override;
 private:
   FunctionStore m_functionStore;
-  LocalContext m_localContext;
+  XContext m_xContext;
   ListController m_listController;
   HeaderViewController m_listHeader;
   StackViewController m_listStackViewController;

apps/graph/graph/graph_view.h

@@ -5,7 +5,6 @@
 #include "../../curve_view.h"
 #include "../../constant.h"
 #include "../function_store.h"
-#include "../local_context.h"
 #include "../../interactive_curve_view_range.h"
 
 namespace Graph {

poincare/Makefile

@@ -6,7 +6,6 @@ objs += $(addprefix poincare/src/,\
   absolute_value.o\
   addition.o\
   binary_operation.o\
-  global_context.o\
   cosine.o\
   derivative.o\
   expression.o\
@@ -15,6 +14,7 @@ objs += $(addprefix poincare/src/,\
   float.o\
   fraction.o\
   function.o\
+  global_context.o\
   integer.o\
   list_data.o\
   leaf_expression.o\
@@ -29,6 +29,7 @@ objs += $(addprefix poincare/src/,\
   subtraction.o\
   symbol.o\
   tangent.o\
+  x_context.o\
 )
 objs += $(addprefix poincare/src/layout/,\
   absolute_value_layout.o\

poincare/include/poincare.h

@@ -24,5 +24,6 @@
 #include <poincare/subtraction.h>
 #include <poincare/symbol.h>
 #include <poincare/tangent.h>
+#include <poincare/x_context.h>
 
 #endif

poincare/include/poincare/derivative.h

@@ -11,8 +11,9 @@ public:
   Expression * cloneWithDifferentOperands(Expression ** newOperands,
       int numberOfOperands, bool cloneOperands = true) const override;
 private:
+//TODO: do something smarter to compute epsilon to gain in precision
   constexpr static float k_epsilon = 0.0001f;
-  constexpr static float k_precision = 0.01f;
+  constexpr static float k_precision = 0.1f;
 };
 
 #endif

poincare/include/poincare/x_context.h

@@ -1,13 +1,12 @@
-#ifndef GRAPH_LOCAL_CONTEXT_H
-#define GRAPH_LOCAL_CONTEXT_H
+#ifndef POINCARE_LOCAL_CONTEXT_H
+#define POINCARE_LOCAL_CONTEXT_H
 
-#include <poincare.h>
+#include <poincare/context.h>
+#include <poincare/float.h>
 
-namespace Graph {
-
-class LocalContext : public Context {
+class XContext : public Context {
 public:
-  LocalContext(Context * parentContext);
+  XContext(Context * parentContext = nullptr);
   void setExpressionForSymbolName(Expression * expression, const Symbol * symbol) override;
   const Expression * expressionForSymbol(const Symbol * symbol) override;
 private:
@@ -15,6 +14,4 @@ private:
   Context * m_parentContext;
 };
 
-}
-
 #endif

poincare/src/derivative.cpp

@@ -1,7 +1,8 @@
 #include <poincare/derivative.h>
 #include <poincare/symbol.h>
 #include <poincare/float.h>
-#include <poincare/context.h>
+#include <poincare/x_context.h>
+
 extern "C" {
 #include <assert.h>
 #include <math.h>
@@ -26,17 +27,14 @@ Expression * Derivative::cloneWithDifferentOperands(Expression** newOperands,
 }
 
 float Derivative::approximate(Context& context) const {
+  XContext xContext = XContext(&context);
   Symbol xSymbol = Symbol('x');
-  const Expression * previousValueForXSymbol = context.expressionForSymbol(&xSymbol);
   Float e = Float(m_args[1]->approximate(context)+k_epsilon);
-  context.setExpressionForSymbolName(&e, &xSymbol);
-  float expressionPlus = m_args[0]->approximate(context);
+  xContext.setExpressionForSymbolName(&e, &xSymbol);
+  float expressionPlus = m_args[0]->approximate(xContext);
   e = Float(m_args[1]->approximate(context)-k_epsilon);
-  context.setExpressionForSymbolName(&e, &xSymbol);
-  float expressionMinus = m_args[0]->approximate(context);
+  xContext.setExpressionForSymbolName(&e, &xSymbol);
+  float expressionMinus = m_args[0]->approximate(xContext);
   float growthRate = (expressionPlus - expressionMinus)/(2*k_epsilon);
-  growthRate = roundf(growthRate/k_precision)*k_precision;
-  e = Float(NAN);
-  context.setExpressionForSymbolName((Expression *)previousValueForXSymbol, &xSymbol);
-  return growthRate;
+  return roundf(growthRate/k_precision)*k_precision;
 }

poincare/src/x_context.cpp

@@ -1,15 +1,12 @@
-#include "local_context.h"
-#include <string.h>
+#include <poincare/x_context.h>
 
-namespace Graph {
-
-LocalContext::LocalContext(::Context * parentContext) :
+XContext::XContext(::Context * parentContext) :
   m_xValue(Float(0.0f)),
   m_parentContext(parentContext)
 {
 }
 
-void LocalContext::setExpressionForSymbolName(Expression * expression, const Symbol * symbol) {
+void XContext::setExpressionForSymbolName(Expression * expression, const Symbol * symbol) {
   if (symbol->name() == 'x') {
   	m_xValue = Float(expression->approximate(*m_parentContext));
   } else {
@@ -17,7 +14,7 @@ void LocalContext::setExpressionForSymbolName(Expression * expression, const Sym
   }
 }
 
-const Expression * LocalContext::expressionForSymbol(const Symbol * symbol) {
+const Expression * XContext::expressionForSymbol(const Symbol * symbol) {
   if (symbol->name() == 'x') {
     return &m_xValue;
   } else {
@@ -25,4 +22,3 @@ const Expression * LocalContext::expressionForSymbol(const Symbol * symbol) {
   }
 }
 
-}