zyn 0.5.4

A proc macro framework with templates, composable elements, and built-in diagnostics
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
162
163
164
165
166
167
168
169
170
171
172
173
174
175

#[zyn::element]
fn three_levels() -> zyn::TokenStream {
    error!("first");
    warn!("second");
    note!("third");
    bail!();
    zyn::TokenStream::new()
}

#[test]
fn preserves_insertion_order() {
    let input: zyn::Input = zyn::parse!("struct Test;" => zyn::syn::DeriveInput)
        .unwrap()
        .into();
    let output = zyn::zyn!(@three_levels());
    zyn::assert_diagnostic_error!(output, "first");
    zyn::assert_diagnostic_warning!(output, "second");
    zyn::assert_diagnostic_note!(output, "third");
}

#[zyn::element]
fn all_four_levels() -> zyn::TokenStream {
    error!("err");
    warn!("warn");
    note!("note");
    help!("help");
    bail!();
    zyn::TokenStream::new()
}

#[test]
fn all_four_levels_accumulate() {
    let input: zyn::Input = zyn::parse!("struct Test;" => zyn::syn::DeriveInput)
        .unwrap()
        .into();
    let output = zyn::zyn!(@all_four_levels());
    zyn::assert_diagnostic_error!(output, "err");
    zyn::assert_diagnostic_warning!(output, "warn");
    zyn::assert_diagnostic_note!(output, "note");
    zyn::assert_diagnostic_help!(output, "help");
}

#[zyn::element]
fn error_and_warning() -> zyn::TokenStream {
    error!("from_a");
    warn!("from_b");
    bail!();
    zyn::TokenStream::new()
}

#[test]
fn merges_in_order() {
    let input: zyn::Input = zyn::parse!("struct Test;" => zyn::syn::DeriveInput)
        .unwrap()
        .into();
    let output = zyn::zyn!(@error_and_warning());
    zyn::assert_diagnostic_error!(output, "from_a");
    zyn::assert_diagnostic_warning!(output, "from_b");
}

#[zyn::element]
fn multiple_errors() -> zyn::TokenStream {
    error!("missing field `x`");
    error!("missing field `y`");
    error!("unknown argument `z`");
    bail!();
    zyn::TokenStream::new()
}

#[test]
fn accumulate_multiple_error_sources() {
    let input: zyn::Input = zyn::parse!("struct Test;" => zyn::syn::DeriveInput)
        .unwrap()
        .into();
    let output = zyn::zyn!(@multiple_errors());
    zyn::assert_diagnostic_error!(output, "missing field `x`");
    zyn::assert_diagnostic_error!(output, "missing field `y`");
    zyn::assert_diagnostic_error!(output, "unknown argument `z`");
}

#[zyn::element]
fn warn_only() -> zyn::TokenStream {
    warn!("just a warning");
    bail!();
    zyn::zyn!(
        struct Foo {}
    )
}

#[test]
fn bail_without_errors_does_not_stop() {
    let input: zyn::Input = zyn::parse!("struct Test;" => zyn::syn::DeriveInput)
        .unwrap()
        .into();
    let output = zyn::zyn!(@warn_only());
    zyn::assert_tokens_contain!(output, "Foo");
}

#[zyn::element]
fn error_then_bail() -> zyn::TokenStream {
    error!("fatal");
    bail!();
    zyn::zyn!(
        struct Foo {}
    )
}

#[test]
fn bail_with_errors_stops() {
    let input: zyn::Input = zyn::parse!("struct Test;" => zyn::syn::DeriveInput)
        .unwrap()
        .into();
    let output = zyn::zyn!(@error_then_bail());
    zyn::assert_diagnostic_error!(output, "fatal");
    assert!(output.tokens().is_empty());
}

#[zyn::element]
pub fn warn_with_output(name: zyn::syn::Ident) -> zyn::TokenStream {
    warn!("deprecated");
    zyn::zyn!(fn {{ name }}() {})
}

#[test]
fn warn_does_not_block_body() {
    let input: zyn::Input = zyn::parse!("struct Test;" => zyn::syn::DeriveInput)
        .unwrap()
        .into();
    let output = zyn::zyn!(
        @warn_with_output(name = zyn::format_ident!("my_fn"))
    );
    zyn::assert_tokens_contain!(output, "my_fn");
}

#[zyn::element]
pub fn note_and_help_with_output(name: zyn::syn::Ident) -> zyn::TokenStream {
    note!("processing `{}`", name);
    help!("consider adding #[derive(Debug)]");
    zyn::zyn!(fn {{ name }}() {})
}

#[test]
fn note_and_help_do_not_block_body() {
    let input: zyn::Input = zyn::parse!("struct Test;" => zyn::syn::DeriveInput)
        .unwrap()
        .into();
    let output = zyn::zyn!(
        @note_and_help_with_output(name = zyn::format_ident!("my_fn"))
    );
    zyn::assert_tokens_contain!(output, "my_fn");
}

#[zyn::element]
pub fn mixed_non_errors_with_output(name: zyn::syn::Ident) -> zyn::TokenStream {
    warn!("field will be removed");
    note!("see migration guide");
    help!("use `new_field` instead");
    zyn::zyn!(
        impl {{ name }} {
            fn validate(&self) -> bool { true }
        }
    )
}

#[test]
fn mixed_non_errors_do_not_block_body() {
    let input: zyn::Input = zyn::parse!("struct Test;" => zyn::syn::DeriveInput)
        .unwrap()
        .into();
    let output = zyn::zyn!(
        @mixed_non_errors_with_output(name = zyn::format_ident!("MyStruct"))
    );
    zyn::assert_tokens_contain!(output, "MyStruct");
    zyn::assert_tokens_contain!(output, "validate");
}