1 files changed, 22 insertions, 0 deletions
diff --git a/impl/Constant.h b/impl/Constant.h
new file mode 100644
index 0000000..bab8cd9
--- /dev/null
+++ b/impl/Constant.h
@@ -0,0 +1,22 @@
+#ifndef CONSTANT_H
+#define CONSTANT_H
+
+#include "Expression.h"
+
+template<class T>
+struct Constant : public Expression<T> {
+  Constant(const T& value) : _value(value) { }
+
+  T value() const {
+    return this->_value;
+  }
+
+  T eval(const std::map<std::string, T>&) const {
+    return _value;
+  }
+
+  private:
+  const T _value;
+};
+
+#endif