[hcheng] advanced programming: namespace and declaration and enable argument-dependent lookup

dev0 · dev0 · commit 14854f61b86a · 2018-03-21T01:46:57.000-04:00
diff --git a/meta_program/chapter_1_specializtion_and_deduction/namespace_and_declaration/framework1.hpp b/meta_program/chapter_1_specializtion_and_deduction/namespace_and_declaration/framework1.hpp
@@ -0,0 +1,16 @@
+#include <iostream>
+#include "macro.hpp"
+MXT_NAMESPACE_BEGIN(framework1)
+template<typename T>
+inline bool is_empty(T const& x) {
+	std::cout << "framework1::is_empty master template " << std::endl;
+	return x.empty();
+}
+
+template<>
+inline bool is_empty(const char* const& x) {
+	std::cout << "framework1::is_empty specification" << std::endl;
+	return x == 0 || *x == 0;
+}
+
+MXT_NAMESPACE_END(framework1)
diff --git a/meta_program/chapter_1_specializtion_and_deduction/namespace_and_declaration/framework2.hpp b/meta_program/chapter_1_specializtion_and_deduction/namespace_and_declaration/framework2.hpp
@@ -0,0 +1,13 @@
+#include "framework1.hpp"
+
+MXT_NAMESPACE_BEGIN(framework2)
+
+using framework1::is_empty;
+template<typename string_t>
+void do_something(string_t const &x) {
+	//if (framework1::is_empty(x)) // it causes error in framework3.cpp when call framework2::do_something(s)
+	if (!is_empty(x))
+	{
+	}
+}
+MXT_NAMESPACE_END(framework2)
diff --git a/meta_program/chapter_1_specializtion_and_deduction/namespace_and_declaration/framework3.cpp b/meta_program/chapter_1_specializtion_and_deduction/namespace_and_declaration/framework3.cpp
@@ -0,0 +1,16 @@
+#include "framework2.hpp"
+namespace framework3 {
+	class EmptyString
+	{
+	};
+	
+	bool is_empty(const EmptyString&x) {
+		std::cout << "framework3::is_empty" << std::endl;
+		return true;
+	}
+}
+
+int main(int argc, char** argv) {
+	framework3::EmptyString s;
+	framework2::do_something(s);
+}
diff --git a/meta_program/chapter_1_specializtion_and_deduction/namespace_and_declaration/macro.hpp b/meta_program/chapter_1_specializtion_and_deduction/namespace_and_declaration/macro.hpp
@@ -0,0 +1,2 @@
+#define MXT_NAMESPACE_BEGIN(self) namespace self {
+#define MXT_NAMESPACE_END(self) }

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	`+#define MXT_NAMESPACE_BEGIN(self) namespace self {`
	`2`	`+#define MXT_NAMESPACE_END(self) }`