rework

include/autoopt/importer.hpp

@@ -0,0 +1,23 @@
+#pragma once
+
+#include <vector>
+#include <Eigen/Eigen>
+#include <generator>
+#include <filesystem>
+#include <fstream>
+
+namespace autoopt {
+struct raw_data {
+  Eigen::VectorXd _xs;
+  std::vector<Eigen::VectorXd> _yss;
+};
+
+std::generator<std::pair<double, double>> parse_dat_file(
+    const std::filesystem::path& filename);
+
+std::pair<std::vector<double>, std::vector<double>> parse_row(auto& iter,
+                                                              auto sentinel);
+
+raw_data read_data(const std::filesystem::path& filename);
+
+}