Move everything into impl/ and add a Makefile.

1 files changed, 47 insertions, 0 deletions

diff --git a/impl/Equation.h b/impl/Equation.h
new file mode 100644
index 0000000..b861768
--- /dev/null
+++ b/impl/Equation.h
@@ -0,0 +1,47 @@
+#ifndef EQUATION_H
+#define EQUATION_H
+
+#include "Variable.h"
+#include "Expression.h"
+#include <map>
+#include <string>
+
+template<class T>
+struct Equation {
+  Equation(const Variable<T>& var, Expression<T>* value)
+    : _var(var), _value(value) { }
+
+  Variable<T> var() const {
+    return _var;
+  }
+  Variable<T> var(const Variable<T>& var) {
+    Variable<T> old_var = _var;
+    _var = var;
+    return _var;
+  }
+
+  Expression<T>* value() const {
+    return _value;
+  }
+  Expression<T>* value(const Expression<T>* value) {
+    Expression<T>* old_value = _value;
+    _value = value;
+    return old_value;
+  }
+
+  std::map<std::string, T> solve(const std::map<std::string, T>& curr) {
+    std::map<std::string, T> result = curr;
+    T last;
+    do {
+      last = result[_var.name()];
+      result[_var.name()] = _value->eval(result);
+    } while (last != result[_var.name()]);
+    return result;
+  }
+
+  private:
+  Variable<T> _var;
+  Expression<T>* _value;
+};
+
+#endif