docs: add README

README.md

@@ -6,12 +6,112 @@
 ![Repo Size](https://img.shields.io/github/repo-size/ghtz08/libctmap?style=flat-square)
 ![Code Size](https://img.shields.io/github/languages/code-size/ghtz08/libctmap?style=flat-square)
 
-一个编译时的 c++ 容器
+一个编译时的 c++ map
+
+## 构建
+
+库本身不需要先编译。可以编译一下自带测试代码：
+
+```bash
+cd <project dir>
+mkdir build
+cd build
+cmake -DBUILD_TEST=ON ..
+```
+
+编译成功即通过测试。
 
 ## 用法
 
+在 CMakeLists.txt 中添加如下代码：
+
+```cmake
+add_subdirectory(libctmap_project_dir)
+target_link_libraries(your_project PRIVATE libctmap)
+```
+
+> 编译器最低需要支持 C++11，也可通过定义宏 `CT_ENABLE_CXX_17` 开启 C++17 来提供一些新的接口。例如：
+
+```c++
+#define CT_ENABLE_CXX_17
+#include <ctmap.hpp>
+```
+
+## 接口
+
+后面的代码假设已经存在这样的环境：
+
+```c++
+#define CT_ENABLE_CXX_17
+#include <ctmap.hpp>
+
+struct k1 {}; struct k2 {}; struct k3 {}; struct k4 {};
+struct v1 {}; struct v2 {}; struct v3 {}; using v4 = ct::i32<4>;
+```
+
+### constructor
+
+```c++
+using m1 = ct::map<>::insert_v<k1, v1>::insert_v<k2, v2>;
+using m2 = ct::map_from_list_t<k1, v1, k2, v2>;
+static_assert(m1::equal<m1, m2>::value, "");
+```
+
+### size
+
+```c++
+using m2 = ct::map_from_list_t<k1, v1, k2, v2>;
+static_assert(m2::size == 2, "");
+```
+
+### contains
+
 ```c++
+using m2 = ct::map_from_list_t<k1, v1, k2, v2>;
+static_assert(m2::contains<k2>::value, "");
+static_assert(!m2::contains<k3>::value, "");
+static_assert(m2::contains_v<k2>);     // c++17
+static_assert(!m2::contains_v<k3>);    // c++17
+```
+
+### equal
+
+```c++
+using m1 = ct::map_from_list_t<k2, v2, k1, v1>;
+using m2 = ct::map_from_list_t<k1, v1, k2, v2>;
+static_assert(m1::equal<m2>::value, "");
+static_assert(!m1::equal<m2>::value, "");
+static_assert(m1::equal_v<m2>);     // c++17
+static_assert(!m1::equal_v<m2>);    // c++17
+```
 
+### at
+
+```c++
+using m = ct::map_from_list_t<k1, v1, k4, v4>;
+static_assert(std::is_same<m::at_t<k1>, v1>::value, "");
+static_assert(std::is_same<m::at_t<k4>, v4>::value, "");
+static_assert(m::at<k4>::value == v4::value, "");
+static_assert(m::at_v<k4> == v4::value);    // c++17
+```
+
+### erase
+
+```c++
+using m1 = ct::map_from_list_t<k1, v1, k2, v2, k3, v3>;
+using m2 = ct::map_from_list_t<k1, v1, k3, v3>;
+using t = m1::erase_t<k2>;
+static_assert(t::equal<m2>::value, "");
+```
+
+### merge
+
+```c++
+using m1 = ct::map_from_list_t<k1, v1, k3, v3>;
+using m2 = ct::map_from_list_t<k2, v2, k4, v4>;
+using m3 = ct::map_from_list_t<k1, v1, k2, v2, k3, v3, k4, v4>;
+using t = m1::merge_t<m2>;
+static_assert(t::equal<m3>::value, "");
 ```
 
 ## 许可证