support bazel complie this project and format code.

learn_class/modern_cpp_30/SFINAE/sfinae paper/lambda.cpp

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+//
+// Created by light on 20-1-6.
+//
+#include <iostream>
+#include "structData.h"
+// Equivalent to:
+struct l5UnamedType {
+    template<typename T>
+    auto operator()(T &t) const -> decltype(t.serialize()) // /!\ This signature is nice for a SFINAE!
+    {
+        return t.serialize();
+    }
+};
+
+
+void fun(A a,B b,C c) {
+
+    // ***** Simple lambda unamed type *****
+    auto l4 = [](int a, int b) { return a + b; };
+    std::cout << l4(4, 5) << std::endl; // Output 9.
+
+    // Equivalent to:
+    struct l4UnamedType {
+        int operator()(int a, int b) const {
+            return a + b;
+        }
+    };
+
+    l4UnamedType l4Equivalent = l4UnamedType();
+    std::cout << l4Equivalent(4, 5) << std::endl; // Output 9 too.
+
+
+
+    // ***** auto parameters lambda unnamed type *****
+
+    // b's type is automagically deduced!
+    auto l5 = [](auto &t) -> decltype(t.serialize()) { return t.serialize(); };
+
+    std::cout << l5(b) << std::endl; // Output: I am a B!
+//    std::cout << l5(a) << std::endl; // Error: no member named 'serialize' in 'A'.
+
+
+    l5UnamedType l5Equivalent = l5UnamedType();
+
+    std::cout << l5Equivalent(b) << std::endl; // Output: I am a B!
+//    std::cout << l5Equivalent(a) << std::endl; // Error: no member named 'serialize' in 'A'.
+
+}
+int main() {
+    A a;
+    B b;
+    C c;
+    auto l1 = [](B &b) { return b.serialize(); }; // Return type figured-out by the return statement.
+    auto l3 = [](B &b) -> std::string { return b.serialize(); }; // Fixed return type.
+    auto l2 = [](B &b) -> decltype(b.serialize()) { return b.serialize(); }; // Return type dependant to the B type.
+
+    std::cout << l1(b) << std::endl; // Output: I am a B!
+    std::cout << l2(b) << std::endl; // Output: I am a B!
+    std::cout << l3(b) << std::endl; // Output: I am a B!
+
+    fun(a,b,c);
+}