1package set
2
3import (
4	"fmt"
5)
6
7// Set is an implementation of the concept of a set: a collection where all
8// values are conceptually either in or out of the set, but the members are
9// not ordered.
10//
11// This type primarily exists to be the internal type of sets in cty, but
12// it is considered to be at the same level of abstraction as Go's built in
13// slice and map collection types, and so should make no cty-specific
14// assumptions.
15//
16// Set operations are not thread safe. It is the caller's responsibility to
17// provide mutex guarantees where necessary.
18//
19// Set operations are not optimized to minimize memory pressure. Mutating
20// a set will generally create garbage and so should perhaps be avoided in
21// tight loops where memory pressure is a concern.
22type Set struct {
23	vals  map[int][]interface{}
24	rules Rules
25}
26
27// NewSet returns an empty set with the membership rules given.
28func NewSet(rules Rules) Set {
29	return Set{
30		vals:  map[int][]interface{}{},
31		rules: rules,
32	}
33}
34
35func NewSetFromSlice(rules Rules, vals []interface{}) Set {
36	s := NewSet(rules)
37	for _, v := range vals {
38		s.Add(v)
39	}
40	return s
41}
42
43func sameRules(s1 Set, s2 Set) bool {
44	return s1.rules.SameRules(s2.rules)
45}
46
47func mustHaveSameRules(s1 Set, s2 Set) {
48	if !sameRules(s1, s2) {
49		panic(fmt.Errorf("incompatible set rules: %#v, %#v", s1.rules, s2.rules))
50	}
51}
52
53// HasRules returns true if and only if the receiving set has the given rules
54// instance as its rules.
55func (s Set) HasRules(rules Rules) bool {
56	return s.rules.SameRules(rules)
57}
58
59// Rules returns the receiving set's rules instance.
60func (s Set) Rules() Rules {
61	return s.rules
62}
63