map/
map.rs

1/// Create a new map collection and insert key-value pairs.
2///
3/// Example with tuple syntax:
4///
5/// ```
6/// # use ::map::*;
7/// let m = map!((1, 2), (3, 4));
8/// ```
9///
10/// Example with arrow syntax:
11///
12/// ```
13/// # use ::map::*;
14/// let m = map!(1 => 2, 3 => 4);
15/// ```
16///
17/// Example with multiple lines and tuple syntax:
18///
19/// ```
20/// # use ::map::*;
21/// let m = map!(
22///     (1, 2),
23///     (3, 4),
24/// );
25/// ```
26///
27/// Example with multiple lines and arrow syntax:
28///
29/// ```rust
30/// # use ::map::*;
31/// let m = map!(
32///     1 => 2,
33///     3 => 4,
34/// );
35/// ```
36///
37/// Equivalent Rust standard code:
38///
39/// ```
40/// # use std::collections::HashMap;
41/// let mut m = HashMap::new();
42/// m.insert(1, 2);
43/// m.insert(3, 4);
44/// ```
45///
46#[allow(unused_macros)]
47#[macro_export]
48macro_rules! map {
49    // tuple syntax
50    ( $(( $k:expr, $v:expr )),* $(,)?) => {
51        {
52            let mut m = ::std::collections::HashMap::new();
53            $(
54                m.insert($k, $v);
55            )*
56            m
57        }
58    };
59    // arrow syntax
60    ( $( $k:expr => $v:expr ),* $(,)?) => {
61        {
62            let mut m = ::std::collections::HashMap::new();
63            $(
64                m.insert($k, $v);
65            )*
66            m
67        }
68    };
69}
70
71#[cfg(test)]
72mod test {
73
74    mod tuple_syntax {
75
76        mod one_line {
77            use std::collections::HashMap;
78
79            #[test]
80            fn trailing_comma() {
81                let x = map!((1, 2), (3, 4),);
82                assert_eq!(x, HashMap::from([(1, 2), (3, 4)]));
83            }
84
85            #[test]
86            fn no_trailing_comma() {
87                let x = map!((1, 2), (3, 4));
88                assert_eq!(x, HashMap::from([(1, 2), (3, 4)]));
89            }
90        }
91
92        mod multiple_lines {
93            use std::collections::HashMap;
94
95            #[test]
96            fn trailing_comma() {
97                let x = map!(
98                    (1, 2),
99                    (3, 4),
100                );
101                assert_eq!(x, HashMap::from([(1, 2), (3, 4)]));
102            }
103
104            #[test]
105            fn no_trailing_comma() {
106                let x = map!(
107                    (1, 2),
108                    (3, 4)
109                );
110                assert_eq!(x, HashMap::from([(1, 2), (3, 4)]));
111            }
112        }
113    }
114
115    mod arrow_syntax {
116
117        mod one_line {
118            use std::collections::HashMap;
119
120            #[test]
121            fn trailing_comma() {
122                let x = map!(1 => 2, 3 => 4,);
123                assert_eq!(x, HashMap::from([(1, 2), (3, 4)]));
124            }
125
126            #[test]
127            fn no_trailing_comma() {
128                let x = map!(1 => 2, 3 => 4);
129                assert_eq!(x, HashMap::from([(1, 2), (3, 4)]));
130            }
131        }
132
133        mod multiple_lines {
134            use std::collections::HashMap;
135
136            #[test]
137            fn trailing_comma() {
138                let x = map!(
139                    1 => 2,
140                    3 => 4,
141                );
142                assert_eq!(x, HashMap::from([(1, 2), (3, 4)]));
143            }
144
145            #[test]
146            fn no_trailing_comma() {
147                let x = map!(
148                    1 => 2,
149                    3 => 4
150                );
151                assert_eq!(x, HashMap::from([(1, 2), (3, 4)]));
152            }
153        }
154    }
155  
156}
map/map.rs

map/
map.rs
