#include "regression_context.h"
  #include <assert.h>
  #include <string.h>
  
  using namespace Poincare;
  using namespace Shared;
  
  namespace Regression {
  
  const Expression * RegressionContext::expressionForSymbol(const Symbol * symbol) {
    if (Symbol::isRegressionSymbol(symbol->name())) {
      const char * seriesName = Symbol::textForSpecialSymbols(symbol->name());
      assert(strlen(seriesName) == 2);
  
      int series = (int)(seriesName[1] - '0') - 1;
      assert(series >= 0 && series < DoublePairStore::k_numberOfSeries);
  
      assert((seriesName[0] == 'X') || (seriesName[0] == 'Y'));
      int storeI = seriesName[0] == 'X' ? 0 : 1;
  
      assert(m_seriesPairIndex >= 0);
      assert(m_seriesPairIndex < m_store->numberOfPairsOfSeries(series));
      m_value = Approximation<double>(m_store->get(series, storeI, m_seriesPairIndex));
      return &m_value;
    } else {
      return m_parentContext->expressionForSymbol(symbol);
    }
  }
  
  }