enum-display 0.2.1

A macro to derive Display for enums
Documentation 
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
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161

#![no_std]

extern crate alloc;
use alloc::string::ToString;
use enum_display::EnumDisplay;

#[derive(EnumDisplay)]
enum SimpleEnum {
    Red,
    Green,
    Blue,
}

#[derive(EnumDisplay)]
enum FormattedEnum {
    #[display("Custom: {variant}")]
    Format,

    #[display("Value is {value}")]
    Data { value: u32 },

    #[display("Tuple: ({0}, {1})")]
    Tuple(i32, i32),
}

#[derive(EnumDisplay)]
#[enum_display(case = "Snake")]
enum CaseTransformEnum {
    CamelCase,
    AnotherExample,
    XmlHttpRequest,
}

#[derive(EnumDisplay)]
enum ComplexEnum {
    Unit,

    Named {
        _field1: u32,
        _field2: alloc::string::String,
    },

    #[display("Complex: {variant} with {field1}")]
    NamedFormat {
        field1: u32,
        field2: alloc::string::String,
    },

    #[allow(dead_code)]
    Tuple(u32, alloc::string::String),

    #[display("Tuple: ({0})")]
    TupleFormat(u32),
}

#[test]
fn test_simple_enum() {
    assert_eq!(SimpleEnum::Red.to_string(), "Red");
    assert_eq!(SimpleEnum::Green.to_string(), "Green");
    assert_eq!(SimpleEnum::Blue.to_string(), "Blue");
}

#[test]
fn test_formatted_enum() {
    assert_eq!(FormattedEnum::Format.to_string(), "Custom: Format");
    assert_eq!(FormattedEnum::Data { value: 42 }.to_string(), "Value is 42");
    assert_eq!(FormattedEnum::Tuple(10, 20).to_string(), "Tuple: (10, 20)");
}

#[test]
fn test_case_transform() {
    assert_eq!(CaseTransformEnum::CamelCase.to_string(), "camel_case");
    assert_eq!(
        CaseTransformEnum::AnotherExample.to_string(),
        "another_example"
    );
    assert_eq!(
        CaseTransformEnum::XmlHttpRequest.to_string(),
        "xml_http_request"
    );
}

#[test]
fn test_complex_enum() {
    assert_eq!(ComplexEnum::Unit.to_string(), "Unit");

    assert_eq!(
        ComplexEnum::Named {
            _field1: 123,
            _field2: "test".into()
        }
        .to_string(),
        "Named"
    );

    assert_eq!(
        ComplexEnum::NamedFormat {
            field1: 456,
            field2: "ignored".into()
        }
        .to_string(),
        "Complex: NamedFormat with 456"
    );

    assert_eq!(ComplexEnum::Tuple(789, "value".into()).to_string(), "Tuple");

    assert_eq!(ComplexEnum::TupleFormat(999).to_string(), "Tuple: (999)");
}

#[test]
fn test_core_fmt_usage() {
    use core::fmt::Write;

    let mut buffer = alloc::string::String::new();

    // Test simple enum
    write!(&mut buffer, "{}", SimpleEnum::Red).unwrap();
    assert_eq!(buffer, "Red");

    buffer.clear();

    // Test formatted enum
    write!(&mut buffer, "{}", FormattedEnum::Format).unwrap();
    assert_eq!(buffer, "Custom: Format");

    buffer.clear();

    // Test case transform
    write!(&mut buffer, "{}", CaseTransformEnum::CamelCase).unwrap();
    assert_eq!(buffer, "camel_case");
}

// Test that Display trait is properly implemented
#[test]
fn test_display_trait() {
    fn accepts_display<T: core::fmt::Display>(item: T) -> alloc::string::String {
        alloc::format!("{item}")
    }

    assert_eq!(accepts_display(SimpleEnum::Red), "Red");
    assert_eq!(accepts_display(FormattedEnum::Format), "Custom: Format");
    assert_eq!(accepts_display(CaseTransformEnum::CamelCase), "camel_case");
}

// Test with generics
#[derive(EnumDisplay)]
enum GenericEnum<T: core::fmt::Display> {
    Value(T),

    #[display("Generic: {0}")]
    FormattedValue(T),
}

#[test]
fn test_generic_enum() {
    assert_eq!(GenericEnum::Value(42u32).to_string(), "Value");
    assert_eq!(
        GenericEnum::FormattedValue(42u32).to_string(),
        "Generic: 42"
    );
}