[C++] The first commit for C++ version

16 tests out of 169 are passing.

1 files changed, 101 insertions, 0 deletions

diff --git a/var.h b/var.h
new file mode 100644
index 0000000..bb7ab31
--- /dev/null
+++ b/var.h
@@ -0,0 +1,101 @@
+#ifndef VAR_H_
+#define VAR_H_
+
+#include <memory>
+#include <string>
+#include <unordered_map>
+
+#include "string_piece.h"
+#include "value.h"
+
+using namespace std;
+
+class Evaluator;
+class Value;
+
+class Var : public Evaluable {
+ public:
+  virtual ~Var();
+
+  virtual const char* Flavor() const = 0;
+  virtual const char* Origin() const = 0;
+  virtual bool IsDefined() const { return true; }
+
+  virtual string DebugString() const = 0;
+
+ protected:
+  Var();
+};
+
+class SimpleVar : public Var {
+ public:
+  SimpleVar(shared_ptr<string> v, const char* origin);
+
+  virtual const char* Flavor() const {
+    return "simple";
+  }
+  virtual const char* Origin() const {
+    return origin_;
+  }
+
+  virtual shared_ptr<string> Eval(Evaluator*) const override {
+    return v_;
+  }
+  virtual void Eval(Evaluator* ev, string* s) const override;
+
+  string DebugString() const override;
+
+ private:
+  shared_ptr<string> v_;
+  const char* origin_;
+};
+
+class RecursiveVar : public Var {
+ public:
+  RecursiveVar(Value* v, const char* origin);
+
+  virtual const char* Flavor() const {
+    return "recursive";
+  }
+  virtual const char* Origin() const {
+    return origin_;
+  }
+
+  virtual void Eval(Evaluator* ev, string* s) const override;
+
+  string DebugString() const override;
+
+ private:
+  Value* v_;
+  const char* origin_;
+};
+
+class UndefinedVar : public Var {
+ public:
+  UndefinedVar();
+
+  virtual const char* Flavor() const {
+    return "undefined";
+  }
+  virtual const char* Origin() const {
+    return "undefined";
+  }
+  virtual bool IsDefined() const { return false; }
+
+  virtual void Eval(Evaluator* ev, string* s) const override;
+
+  string DebugString() const override;
+};
+
+extern UndefinedVar* kUndefined;
+
+class Vars : public unordered_map<StringPiece, Var*> {
+ public:
+  ~Vars();
+
+  Var* Lookup(StringPiece name) const;
+
+  void Assign(StringPiece name, Var* v);
+};
+
+#endif  // VAR_H_