[poincare] Create a class n_context

Change-Id: Icce8f8fe79c07e73587d8c0563e930c1b1e6b308

poincare/Makefile

@@ -23,6 +23,7 @@ objs += $(addprefix poincare/src/,\
   logarithm.o\
   matrix.o\
   matrix_data.o\
+  n_context.o\
   nth_root.o\
   opposite.o\
   parenthesis.o\

poincare/include/poincare.h

@@ -18,6 +18,7 @@
 #include <poincare/logarithm.h>
 #include <poincare/matrix.h>
 #include <poincare/matrix_data.h>
+#include <poincare/n_context.h>
 #include <poincare/nth_root.h>
 #include <poincare/opposite.h>
 #include <poincare/parenthesis.h>

poincare/include/poincare/n_context.h

@@ -0,0 +1,17 @@
+#ifndef POINCARE_N_CONTEXT_H
+#define POINCARE_N_CONTEXT_H
+
+#include <poincare/context.h>
+#include <poincare/float.h>
+
+class NContext : public Context {
+public:
+  NContext(Context * parentContext = nullptr);
+  void setExpressionForSymbolName(Expression * expression, const Symbol * symbol) override;
+  const Expression * expressionForSymbol(const Symbol * symbol) override;
+private:
+  Float m_nValue;
+  Context * m_parentContext;
+};
+
+#endif

poincare/include/poincare/x_context.h

@@ -1,5 +1,5 @@
-#ifndef POINCARE_LOCAL_CONTEXT_H
-#define POINCARE_LOCAL_CONTEXT_H
+#ifndef POINCARE_X_CONTEXT_H
+#define POINCARE_X_CONTEXT_H
 
 #include <poincare/context.h>
 #include <poincare/float.h>

poincare/src/n_context.cpp

@@ -0,0 +1,24 @@
+#include <poincare/n_context.h>
+
+NContext::NContext(::Context * parentContext) :
+  m_nValue(Float(0.0f)),
+  m_parentContext(parentContext)
+{
+}
+
+void NContext::setExpressionForSymbolName(Expression * expression, const Symbol * symbol) {
+  if (symbol->name() == 'n') {
+  	m_nValue = Float((int)expression->approximate(*m_parentContext));
+  } else {
+    m_parentContext->setExpressionForSymbolName(expression, symbol);
+  }
+}
+
+const Expression * NContext::expressionForSymbol(const Symbol * symbol) {
+  if (symbol->name() == 'n') {
+    return &m_nValue;
+  } else {
+    return m_parentContext->expressionForSymbol(symbol);
+  }
+}
+