-
Notifications
You must be signed in to change notification settings - Fork 0
/
Builder.cpp
125 lines (101 loc) · 3.23 KB
/
Builder.cpp
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
// Some objects are simple and can be created in a single constructor call
// other object require lot of ceremony to create
// having constructor with 10+ arguments is not productive
// instead pice-wise construction
// builder provide an API for constructing an object step-by-step
#include <iostream>
#include <string>
#include <vector>
#include <sstream>
#include <memory>
using namespace std;
struct HtmlBuilder;
struct HtmlElement
{
// friend class HtmlBuilder
string name;
string text;
vector<HtmlElement> elements;
const size_t indent_size = 2; // 들여쓰기 크기
// make HtmlElement constructor private will force to use Builder
HtmlElement() {}
HtmlElement(const string& name, const string& text)
: name(name),
text(text)
{
}
string str(int indent = 0) const
{
ostringstream oss;
string i(indent_size * indent, ' ');
oss << i << "<" << name << ">" << endl;
if (text.size() > 0)
oss << string(indent_size * (indent + 1), ' ') << text << endl;
for (const auto& e : elements)
oss << e.str(indent + 1); // recursive function
oss << i << "</" << name << ">" << endl;
return oss.str();
}
// show client there is builder api. instead of returning value hoping for return value optimization
static unique_ptr<HtmlBuilder> build(string root_name) // rename this to create
{
return make_unique<HtmlBuilder>(root_name);
}
};
// This is builder
struct HtmlBuilder
{
HtmlBuilder(string root_name)
{
root.name = root_name;
}
// void to start with
HtmlBuilder& add_child(string child_name, string child_text)
{
HtmlElement e{ child_name, child_text };
root.elements.emplace_back(e);
return *this;
}
// pointer based
HtmlBuilder* add_child_2(string child_name, string child_text)
{
HtmlElement e{ child_name, child_text };
root.elements.emplace_back(e);
return this;
}
string str() { return root.str(); }
// last operation, 변환 연산자, HtmlElement에 대입되면 자동 변환
operator HtmlElement() const { return root; } // in this case returning copy of it
// return std::move(root);
HtmlElement root;
// recommand more reference API than pointer API
// HtmlElement build() { return root; } // better and more sensible api, because client can't know there is implicit conversion to HtmlElement
};
int demo()
{
// <p>hello</p>
auto text = "hello";
string output;
output += "<p>";
output += text;
output += "</p>";
printf("<p>%s</p>", text);
// <ul><li>hello</li><li>world</li></ul>
string words[] = { "hello", "world" };
ostringstream oss;
oss << "<ul>";
for (auto w : words)
oss << " <li>" << w << "</li>";
oss << "</ul>";
printf(oss.str().c_str());
// easier
HtmlBuilder builder{ "ul" };
builder.add_child("li", "hello").add_child("li", "world"); // fluent interface
cout << builder.str() << endl;
// static builder in HtmlElement
auto builder2 = HtmlElement::build("ul")
->add_child_2("li", "hello")->add_child_2("li", "world");
cout << builder2 << endl;
getchar();
return 0;
}