1 files changed, 87 insertions, 0 deletions
diff --git a/cells.hpp b/cells.hpp
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--- /dev/null
+++ b/cells.hpp
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+// Copyright 2012, Matthias Andreas Benkard.
+
+#pragma once
+
+#ifndef CELLS_HPP
+#define CELLS_HPP
+
+#include <functional>
+#include <memory>
+#include <forward_list>
+#include <algorithm>
+
+namespace cells {
+
+  class observer : public virtual std::enable_shared_from_this<observer> {
+  private:
+    std::forward_list<std::weak_ptr<observer>> dependents;
+    std::forward_list<std::shared_ptr<observer>> dependencies;
+
+    void clear_dependencies();
+    void mark_dependents();
+
+  protected:
+    void mark();
+
+  public:
+    void add_dependent(std::shared_ptr<observer> dependent);
+    void remove_dependent(observer* dependent);
+    void reset_dependencies(std::forward_list<std::shared_ptr<observer>> const& newdeps);
+
+    virtual void update() = 0;
+
+    virtual ~observer();
+  };
+
+
+  template <typename T>
+  class cell : public observer {
+  private:
+    T current_value;
+
+  protected:
+    cell();
+    virtual void update();
+    virtual T recompute(T) = 0;
+    virtual T init() = 0;
+
+  public:
+    T& get();
+    T& operator *() { return get(); }
+    //T operator ()() { return get(); }
+    operator T() { return get(); }
+
+    virtual ~cell();
+  };
+
+
+  template <typename T>
+  class formula_cell : public cell<T> {
+    //friend class std::shared_ptr<formula_cell<T>>;
+    //friend std::shared_ptr<formula_cell<T>> std::make_shared<formula_cell<T>>();
+  private:
+    std::function<T ()> formula;
+    std::function<T (T old)> alt_formula;
+
+  protected:
+    formula_cell() { }
+    virtual T recompute(T);
+    virtual T init();
+
+  public:
+    //static std::shared_ptr<formula_cell<T>> make() { return std::make_shared<formula_cell<T>>(); }
+    static std::shared_ptr<formula_cell<T>> make() { return std::shared_ptr<formula_cell<T>>(new formula_cell()); }
+
+    void reset(T value);
+    void reset(std::function<T ()>);
+    void reset(std::function<T ()>, std::function<T (T old)>);
+
+    virtual ~formula_cell();
+  };
+
+  void with_transaction(std::function<void ()>);
+}
+
+#endif //CELLS_HPP
+
+#include "cells-impl.hpp"