1 | #pragma once |
---|
2 | #include <cstddef> |
---|
3 | #include <exception> |
---|
4 | #include <iomanip> |
---|
5 | #include <memory> |
---|
6 | #include <ostream> |
---|
7 | #include <string> |
---|
8 | #include <typeinfo> |
---|
9 | #include <typeindex> |
---|
10 | |
---|
11 | class bad_cast : public std::exception { |
---|
12 | std::string why; |
---|
13 | public: |
---|
14 | bad_cast( const std::type_index& f, const std::type_index& t ) : std::exception() { |
---|
15 | why = std::string{"bad cast of "} + f.name() + " to " + t.name(); |
---|
16 | } |
---|
17 | ~bad_cast() override = default; |
---|
18 | |
---|
19 | const char* what() const noexcept override { return why.c_str(); } |
---|
20 | }; |
---|
21 | |
---|
22 | template<typename T> std::type_index class_of() { return { typeid(T) }; } |
---|
23 | |
---|
24 | template<typename T> using ptr = std::unique_ptr<T>; |
---|
25 | |
---|
26 | struct object { |
---|
27 | std::type_index get_class() const { return { this ? typeid(*this) : typeid(std::nullptr_t) }; } |
---|
28 | |
---|
29 | template<typename T> T& as() { |
---|
30 | T* p = dynamic_cast<T*>(this); |
---|
31 | if ( !p ) throw bad_cast{ get_class(), class_of<T>() }; |
---|
32 | return *p; |
---|
33 | } |
---|
34 | |
---|
35 | template<typename T> const T& as() const { |
---|
36 | const T* p = dynamic_cast<const T*>(this); |
---|
37 | if ( !p ) throw bad_cast{ get_class(), class_of<T>() }; |
---|
38 | return *p; |
---|
39 | } |
---|
40 | |
---|
41 | virtual ptr<object> new_inst() const = 0; |
---|
42 | virtual ptr<object> new_copy() const = 0; |
---|
43 | virtual object& operator= (const object&) = 0; |
---|
44 | virtual ~object() = default; |
---|
45 | }; |
---|
46 | |
---|
47 | template<typename T, typename... Args> static inline ptr<T> make(Args&&... args) { |
---|
48 | return std::make_unique<T>(std::forward<Args>(args)...); |
---|
49 | } |
---|
50 | |
---|
51 | template<typename To, typename From> |
---|
52 | ptr<To> as_ptr( ptr<From>&& p ) { return ptr<To>{ &p.release()->template as<To>() }; } |
---|
53 | |
---|
54 | struct ordered : public virtual object { |
---|
55 | virtual int cmp(const ordered&) const = 0; |
---|
56 | |
---|
57 | bool operator< (const ordered& that) const { return cmp(that) < 0; } |
---|
58 | bool operator<= ( const ordered& that ) const { return cmp(that) <= 0; } |
---|
59 | bool operator== ( const ordered& that ) const { return cmp(that) == 0; } |
---|
60 | bool operator!= ( const ordered& that ) const { return cmp(that) != 0; } |
---|
61 | bool operator> ( const ordered& that ) const { return cmp(that) > 0; } |
---|
62 | bool operator>= ( const ordered& that ) const { return cmp(that) >= 0; } |
---|
63 | }; |
---|
64 | |
---|
65 | struct printable : public virtual object { |
---|
66 | virtual void print(std::ostream&) const = 0; |
---|
67 | }; |
---|
68 | |
---|
69 | class character : public ordered, public printable { |
---|
70 | char x; |
---|
71 | public: |
---|
72 | character() = default; |
---|
73 | character(char x) : x(x) {} |
---|
74 | character(const character&) = default; |
---|
75 | character(character&&) = default; |
---|
76 | ptr<object> new_inst() const override { return make<character>(); } |
---|
77 | ptr<object> new_copy() const override { return make<character>(*this); } |
---|
78 | character& operator= (const character& that) { |
---|
79 | x = that.x; |
---|
80 | return *this; |
---|
81 | } |
---|
82 | object& operator= (const object& that) override { return *this = that.as<character>(); } /***/ |
---|
83 | character& operator= (character&&) = default; |
---|
84 | ~character() override = default; |
---|
85 | |
---|
86 | int cmp(const character& that) const { return x == that.x ? 0 : x < that.x ? -1 : 1; } |
---|
87 | int cmp(const ordered& that) const override { return cmp( that.as<character>() ); } /***/ |
---|
88 | |
---|
89 | void print(std::ostream& out) const override { |
---|
90 | if ( 0x20 <= x && x <= 0x7E ) { out << "'" << x << "'"; } |
---|
91 | else { out << "'\\" << std::hex << (unsigned int)x << std::setbase(0) << "'"; } |
---|
92 | } |
---|
93 | }; |
---|
94 | |
---|
95 | class short_integer : public ordered, public printable { |
---|
96 | short x; |
---|
97 | public: |
---|
98 | short_integer() = default; |
---|
99 | short_integer(short x) : x(x) {} |
---|
100 | short_integer(const short_integer&) = default; |
---|
101 | short_integer(short_integer&&) = default; |
---|
102 | ptr<object> new_inst() const override { return make<short_integer>(); } |
---|
103 | ptr<object> new_copy() const override { return make<short_integer>(*this); } |
---|
104 | short_integer& operator= (const short_integer& that) { |
---|
105 | x = that.x; |
---|
106 | return *this; |
---|
107 | } |
---|
108 | object& operator= (const object& that) override { return *this = that.as<short_integer>(); } /***/ |
---|
109 | short_integer& operator= (short_integer&&) = default; |
---|
110 | ~short_integer() override = default; |
---|
111 | |
---|
112 | int cmp(const short_integer& that) const { return x == that.x ? 0 : x < that.x ? -1 : 1; } |
---|
113 | int cmp(const ordered& that) const override { return cmp( that.as<short_integer>() ); } /***/ |
---|
114 | |
---|
115 | void print(std::ostream& out) const override { out << x; } |
---|
116 | }; |
---|
117 | |
---|
118 | class integer : public ordered, public printable { |
---|
119 | int x; |
---|
120 | public: |
---|
121 | integer() = default; |
---|
122 | integer(int x) : x(x) {} |
---|
123 | integer(const integer&) = default; |
---|
124 | integer(integer&&) = default; |
---|
125 | ptr<object> new_inst() const override { return make<integer>(); } |
---|
126 | ptr<object> new_copy() const override { return make<integer>(*this); } |
---|
127 | integer& operator= (const integer& that) { |
---|
128 | x = that.x; |
---|
129 | return *this; |
---|
130 | } |
---|
131 | object& operator= (const object& that) override { return *this = that.as<integer>(); } /***/ |
---|
132 | integer& operator= (integer&&) = default; |
---|
133 | ~integer() override = default; |
---|
134 | |
---|
135 | int cmp(const integer& that) const { return x == that.x ? 0 : x < that.x ? -1 : 1; } |
---|
136 | int cmp(const ordered& that) const override { return cmp( that.as<integer>() ); } /***/ |
---|
137 | |
---|
138 | void print(std::ostream& out) const override { out << x; } |
---|
139 | }; |
---|
140 | |
---|
141 | class pair : public ordered, public printable { |
---|
142 | ptr<object> x; |
---|
143 | ptr<object> y; |
---|
144 | public: |
---|
145 | pair() = default; |
---|
146 | pair(ptr<object>&& x, ptr<object>&& y) : x(std::move(x)), y(std::move(y)) {} |
---|
147 | pair(const pair& that) : x(that.x->new_copy()), y(that.y->new_copy()) {} |
---|
148 | pair(pair&& that) : x(std::move(that.x)), y(std::move(that.y)) {} |
---|
149 | ptr<object> new_inst() const override { return make<pair>(); } |
---|
150 | ptr<object> new_copy() const override { return make<pair>(x->new_copy(), y->new_copy()); } |
---|
151 | pair& operator= (const pair& that) { |
---|
152 | x = that.x->new_copy(); |
---|
153 | y = that.y->new_copy(); |
---|
154 | return *this; |
---|
155 | } |
---|
156 | object& operator= (const object& that) override { return *this = that.as<pair>(); } /***/ |
---|
157 | pair& operator= (pair&& that) { |
---|
158 | x = std::move(that.x); |
---|
159 | y = std::move(that.y); |
---|
160 | return *this; |
---|
161 | } |
---|
162 | ~pair() override = default; |
---|
163 | |
---|
164 | int cmp(const pair& that) const { |
---|
165 | int c = x->as<ordered>().cmp( that.x->as<ordered>() ); /***/ |
---|
166 | if ( c != 0 ) return c; |
---|
167 | return y->as<ordered>().cmp( that.y->as<ordered>() ); /***/ |
---|
168 | } |
---|
169 | int cmp(const ordered& that) const override { return cmp( that.as<pair>() ); } /***/ |
---|
170 | |
---|
171 | void print(std::ostream& out) const override { |
---|
172 | out << "["; |
---|
173 | x->as<printable>().print(out); /***/ |
---|
174 | out << ", "; |
---|
175 | y->as<printable>().print(out); /***/ |
---|
176 | out << "]"; |
---|
177 | } |
---|
178 | }; |
---|