# Source file test/typeparam/sets.go

```     1  // run
2
4  // Use of this source code is governed by a BSD-style
6
7  package main
8
9  import (
10  	"fmt"
11  	"sort"
12  )
13
14  // _Equal reports whether two slices are equal: the same length and all
15  // elements equal. All floating point NaNs are considered equal.
16  func _SliceEqual[Elem comparable](s1, s2 []Elem) bool {
17  	if len(s1) != len(s2) {
18  		return false
19  	}
20  	for i, v1 := range s1 {
21  		v2 := s2[i]
22  		if v1 != v2 {
23  			isNaN := func(f Elem) bool { return f != f }
24  			if !isNaN(v1) || !isNaN(v2) {
25  				return false
26  			}
27  		}
28  	}
29  	return true
30  }
31
32  // A _Set is a set of elements of some type.
33  type _Set[Elem comparable] struct {
34  	m map[Elem]struct{}
35  }
36
37  // _Make makes a new set.
38  func _Make[Elem comparable]() _Set[Elem] {
39  	return _Set[Elem]{m: make(map[Elem]struct{})}
40  }
41
43  func (s _Set[Elem]) Add(v Elem) {
44  	s.m[v] = struct{}{}
45  }
46
47  // Delete removes an element from a set. If the element is not present
48  // in the set, this does nothing.
49  func (s _Set[Elem]) Delete(v Elem) {
50  	delete(s.m, v)
51  }
52
53  // Contains reports whether v is in the set.
54  func (s _Set[Elem]) Contains(v Elem) bool {
55  	_, ok := s.m[v]
56  	return ok
57  }
58
59  // Len returns the number of elements in the set.
60  func (s _Set[Elem]) Len() int {
61  	return len(s.m)
62  }
63
64  // Values returns the values in the set.
65  // The values will be in an indeterminate order.
66  func (s _Set[Elem]) Values() []Elem {
67  	r := make([]Elem, 0, len(s.m))
68  	for v := range s.m {
69  		r = append(r, v)
70  	}
71  	return r
72  }
73
74  // _Equal reports whether two sets contain the same elements.
75  func _Equal[Elem comparable](s1, s2 _Set[Elem]) bool {
76  	if len(s1.m) != len(s2.m) {
77  		return false
78  	}
79  	for v1 := range s1.m {
80  		if !s2.Contains(v1) {
81  			return false
82  		}
83  	}
84  	return true
85  }
86
87  // Copy returns a copy of s.
88  func (s _Set[Elem]) Copy() _Set[Elem] {
89  	r := _Set[Elem]{m: make(map[Elem]struct{}, len(s.m))}
90  	for v := range s.m {
91  		r.m[v] = struct{}{}
92  	}
93  	return r
94  }
95
97  func (s _Set[Elem]) AddSet(s2 _Set[Elem]) {
98  	for v := range s2.m {
99  		s.m[v] = struct{}{}
100  	}
101  }
102
103  // SubSet removes all elements in s2 from s.
104  // Values in s2 that are not in s are ignored.
105  func (s _Set[Elem]) SubSet(s2 _Set[Elem]) {
106  	for v := range s2.m {
107  		delete(s.m, v)
108  	}
109  }
110
111  // Intersect removes all elements from s that are not present in s2.
112  // Values in s2 that are not in s are ignored.
113  func (s _Set[Elem]) Intersect(s2 _Set[Elem]) {
114  	for v := range s.m {
115  		if !s2.Contains(v) {
116  			delete(s.m, v)
117  		}
118  	}
119  }
120
121  // Iterate calls f on every element in the set.
122  func (s _Set[Elem]) Iterate(f func(Elem)) {
123  	for v := range s.m {
124  		f(v)
125  	}
126  }
127
128  // Filter deletes any elements from s for which f returns false.
129  func (s _Set[Elem]) Filter(f func(Elem) bool) {
130  	for v := range s.m {
131  		if !f(v) {
132  			delete(s.m, v)
133  		}
134  	}
135  }
136
137  func TestSet() {
138  	s1 := _Make[int]()
139  	if got := s1.Len(); got != 0 {
140  		panic(fmt.Sprintf("Len of empty set = %d, want 0", got))
141  	}
145  	if got := s1.Len(); got != 1 {
146  		panic(fmt.Sprintf("(%v).Len() == %d, want 1", s1, got))
147  	}
151  	if got := s1.Len(); got != 4 {
152  		panic(fmt.Sprintf("(%v).Len() == %d, want 4", s1, got))
153  	}
154  	if !s1.Contains(1) {
155  		panic(fmt.Sprintf("(%v).Contains(1) == false, want true", s1))
156  	}
157  	if s1.Contains(5) {
158  		panic(fmt.Sprintf("(%v).Contains(5) == true, want false", s1))
159  	}
160  	vals := s1.Values()
161  	sort.Ints(vals)
162  	w1 := []int{1, 2, 3, 4}
163  	if !_SliceEqual(vals, w1) {
164  		panic(fmt.Sprintf("(%v).Values() == %v, want %v", s1, vals, w1))
165  	}
166  }
167
168  func TestEqual() {
169  	s1 := _Make[string]()
170  	s2 := _Make[string]()
171  	if !_Equal(s1, s2) {
172  		panic(fmt.Sprintf("_Equal(%v, %v) = false, want true", s1, s2))
173  	}
176  	if got := s1.Len(); got != 2 {
177  		panic(fmt.Sprintf("(%v).Len() == %d, want 2", s1, got))
178  	}
179  	if _Equal(s1, s2) {
180  		panic(fmt.Sprintf("_Equal(%v, %v) = true, want false", s1, s2))
181  	}
182  }
183
184  func TestCopy() {
185  	s1 := _Make[float64]()
187  	s2 := s1.Copy()
188  	if !_Equal(s1, s2) {
189  		panic(fmt.Sprintf("_Equal(%v, %v) = false, want true", s1, s2))
190  	}
192  	if _Equal(s1, s2) {
193  		panic(fmt.Sprintf("_Equal(%v, %v) = true, want false", s1, s2))
194  	}
195  }
196
198  	s1 := _Make[int]()
201  	s2 := _Make[int]()
205  	if got := s1.Len(); got != 3 {
206  		panic(fmt.Sprintf("(%v).Len() == %d, want 3", s1, got))
207  	}
209  	if !_Equal(s1, s2) {
210  		panic(fmt.Sprintf("_Equal(%v, %v) = false, want true", s1, s2))
211  	}
212  }
213
214  func TestSubSet() {
215  	s1 := _Make[int]()
218  	s2 := _Make[int]()
221  	s1.SubSet(s2)
222  	if got := s1.Len(); got != 1 {
223  		panic(fmt.Sprintf("(%v).Len() == %d, want 1", s1, got))
224  	}
225  	if vals, want := s1.Values(), []int{1}; !_SliceEqual(vals, want) {
226  		panic(fmt.Sprintf("after SubSet got %v, want %v", vals, want))
227  	}
228  }
229
230  func TestIntersect() {
231  	s1 := _Make[int]()
234  	s2 := _Make[int]()
237  	s1.Intersect(s2)
238  	if got := s1.Len(); got != 1 {
239  		panic(fmt.Sprintf("(%v).Len() == %d, want 1", s1, got))
240  	}
241  	if vals, want := s1.Values(), []int{2}; !_SliceEqual(vals, want) {
242  		panic(fmt.Sprintf("after Intersect got %v, want %v", vals, want))
243  	}
244  }
245
246  func TestIterate() {
247  	s1 := _Make[int]()
252  	tot := 0
253  	s1.Iterate(func(i int) { tot += i })
254  	if tot != 10 {
255  		panic(fmt.Sprintf("total of %v == %d, want 10", s1, tot))
256  	}
257  }
258
259  func TestFilter() {
260  	s1 := _Make[int]()
264  	s1.Filter(func(v int) bool { return v%2 == 0 })
265  	if vals, want := s1.Values(), []int{2}; !_SliceEqual(vals, want) {
266  		panic(fmt.Sprintf("after Filter got %v, want %v", vals, want))
267  	}
268
269  }
270
271  func main() {
272  	TestSet()
273  	TestEqual()
274  	TestCopy()