From 2b2a05148e76c73cb194214c4ec1aa863794d43f Mon Sep 17 00:00:00 2001
From: ToruNiina <niina.toru.68u@gmail.com>
Date: Sat, 8 Dec 2018 20:18:50 +0900
Subject: [PATCH] add from_string to utility

---
 tests/test_utility.cpp | 12 ++++++++++++
 toml/utility.hpp       | 11 +++++++++++
 2 files changed, 23 insertions(+)

diff --git a/tests/test_utility.cpp b/tests/test_utility.cpp
index dd08f2f..b879c54 100644
--- a/tests/test_utility.cpp
+++ b/tests/test_utility.cpp
@@ -68,3 +68,15 @@ BOOST_AUTO_TEST_CASE(test_concat_to_string)
     const std::string cat = toml::concat_to_string("foo", "bar", 42);
     BOOST_CHECK(cat == "foobar42");
 }
+
+BOOST_AUTO_TEST_CASE(test_from_string)
+{
+    {
+        const std::string str("123");
+        BOOST_CHECK_EQUAL(toml::from_string<int>(str, 0), 123);
+    }
+    {
+        const std::string str("01");
+        BOOST_CHECK_EQUAL(toml::from_string<int>(str, 0), 1);
+    }
+}
diff --git a/toml/utility.hpp b/toml/utility.hpp
index 2e7b0f0..26eff2d 100644
--- a/toml/utility.hpp
+++ b/toml/utility.hpp
@@ -62,5 +62,16 @@ std::string concat_to_string(Ts&& ... args)
     return detail::concat_to_string_impl(oss, std::forward<Ts>(args) ...);
 }
 
+template<typename T, typename U>
+T from_string(const std::string& str, U&& opt)
+{
+    T v(std::forward<U>(opt));
+    std::istringstream iss(str);
+    iss >> v;
+    return v;
+}
+
+
+
 }// toml
 #endif // TOML11_UTILITY