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
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
|
//! Functions for string case manipulation, such as detecting the identifier case,
//! and converting it into appropriate form.
// Code that was taken from rustc was taken at commit 89fdb30,
// from file /compiler/rustc_lint/src/nonstandard_style.rs
/// Converts an identifier to an UpperCamelCase form.
/// Returns `None` if the string is already is UpperCamelCase.
pub(crate) fn to_camel_case(ident: &str) -> Option<String> {
if is_camel_case(ident) {
return None;
}
// Taken from rustc.
let ret = ident
.trim_matches('_')
.split('_')
.filter(|component| !component.is_empty())
.map(|component| {
let mut camel_cased_component = String::new();
let mut new_word = true;
let mut prev_is_lower_case = true;
for c in component.chars() {
// Preserve the case if an uppercase letter follows a lowercase letter, so that
// `camelCase` is converted to `CamelCase`.
if prev_is_lower_case && c.is_uppercase() {
new_word = true;
}
if new_word {
camel_cased_component.push_str(&c.to_uppercase().to_string());
} else {
camel_cased_component.push_str(&c.to_lowercase().to_string());
}
prev_is_lower_case = c.is_lowercase();
new_word = false;
}
camel_cased_component
})
.fold((String::new(), None), |(acc, prev): (String, Option<String>), next| {
// separate two components with an underscore if their boundary cannot
// be distinguished using a uppercase/lowercase case distinction
let join = if let Some(prev) = prev {
let l = prev.chars().last().unwrap();
let f = next.chars().next().unwrap();
!char_has_case(l) && !char_has_case(f)
} else {
false
};
(acc + if join { "_" } else { "" } + &next, Some(next))
})
.0;
Some(ret)
}
/// Converts an identifier to a lower_snake_case form.
/// Returns `None` if the string is already in lower_snake_case.
pub(crate) fn to_lower_snake_case(ident: &str) -> Option<String> {
if is_lower_snake_case(ident) {
return None;
} else if is_upper_snake_case(ident) {
return Some(ident.to_lowercase());
}
Some(stdx::to_lower_snake_case(ident))
}
/// Converts an identifier to an UPPER_SNAKE_CASE form.
/// Returns `None` if the string is already is UPPER_SNAKE_CASE.
pub(crate) fn to_upper_snake_case(ident: &str) -> Option<String> {
if is_upper_snake_case(ident) {
return None;
} else if is_lower_snake_case(ident) {
return Some(ident.to_uppercase());
}
Some(stdx::to_upper_snake_case(ident))
}
// Taken from rustc.
// Modified by replacing the use of unstable feature `array_windows`.
fn is_camel_case(name: &str) -> bool {
let name = name.trim_matches('_');
if name.is_empty() {
return true;
}
let mut fst = None;
// start with a non-lowercase letter rather than non-uppercase
// ones (some scripts don't have a concept of upper/lowercase)
!name.chars().next().unwrap().is_lowercase()
&& !name.contains("__")
&& !name.chars().any(|snd| {
let ret = match (fst, snd) {
(None, _) => false,
(Some(fst), snd) => {
char_has_case(fst) && snd == '_' || char_has_case(snd) && fst == '_'
}
};
fst = Some(snd);
ret
})
}
fn is_lower_snake_case(ident: &str) -> bool {
is_snake_case(ident, char::is_uppercase)
}
fn is_upper_snake_case(ident: &str) -> bool {
is_snake_case(ident, char::is_lowercase)
}
// Taken from rustc.
// Modified to allow checking for both upper and lower snake case.
fn is_snake_case<F: Fn(char) -> bool>(ident: &str, wrong_case: F) -> bool {
if ident.is_empty() {
return true;
}
let ident = ident.trim_matches('_');
let mut allow_underscore = true;
ident.chars().all(|c| {
allow_underscore = match c {
'_' if !allow_underscore => return false,
'_' => false,
// It would be more obvious to check for the correct case,
// but some characters do not have a case.
c if !wrong_case(c) => true,
_ => return false,
};
true
})
}
// Taken from rustc.
fn char_has_case(c: char) -> bool {
c.is_lowercase() || c.is_uppercase()
}
#[cfg(test)]
mod tests {
use super::*;
use expect_test::{expect, Expect};
fn check<F: Fn(&str) -> Option<String>>(fun: F, input: &str, expect: Expect) {
// `None` is translated to empty string, meaning that there is nothing to fix.
let output = fun(input).unwrap_or_default();
expect.assert_eq(&output);
}
#[test]
fn test_to_lower_snake_case() {
check(to_lower_snake_case, "lower_snake_case", expect![[""]]);
check(to_lower_snake_case, "UPPER_SNAKE_CASE", expect![["upper_snake_case"]]);
check(to_lower_snake_case, "Weird_Case", expect![["weird_case"]]);
check(to_lower_snake_case, "CamelCase", expect![["camel_case"]]);
check(to_lower_snake_case, "lowerCamelCase", expect![["lower_camel_case"]]);
check(to_lower_snake_case, "a", expect![[""]]);
check(to_lower_snake_case, "abc", expect![[""]]);
}
#[test]
fn test_to_camel_case() {
check(to_camel_case, "CamelCase", expect![[""]]);
check(to_camel_case, "CamelCase_", expect![[""]]);
check(to_camel_case, "_CamelCase", expect![[""]]);
check(to_camel_case, "lowerCamelCase", expect![["LowerCamelCase"]]);
check(to_camel_case, "lower_snake_case", expect![["LowerSnakeCase"]]);
check(to_camel_case, "UPPER_SNAKE_CASE", expect![["UpperSnakeCase"]]);
check(to_camel_case, "Weird_Case", expect![["WeirdCase"]]);
check(to_camel_case, "name", expect![["Name"]]);
check(to_camel_case, "A", expect![[""]]);
check(to_camel_case, "AABB", expect![[""]]);
// Taken from rustc: /compiler/rustc_lint/src/nonstandard_style/tests.rs
check(to_camel_case, "X86_64", expect![[""]]);
check(to_camel_case, "x86__64", expect![["X86_64"]]);
check(to_camel_case, "Abc_123", expect![["Abc123"]]);
check(to_camel_case, "A1_b2_c3", expect![["A1B2C3"]]);
}
#[test]
fn test_to_upper_snake_case() {
check(to_upper_snake_case, "UPPER_SNAKE_CASE", expect![[""]]);
check(to_upper_snake_case, "lower_snake_case", expect![["LOWER_SNAKE_CASE"]]);
check(to_upper_snake_case, "Weird_Case", expect![["WEIRD_CASE"]]);
check(to_upper_snake_case, "CamelCase", expect![["CAMEL_CASE"]]);
check(to_upper_snake_case, "lowerCamelCase", expect![["LOWER_CAMEL_CASE"]]);
check(to_upper_snake_case, "A", expect![[""]]);
check(to_upper_snake_case, "ABC", expect![[""]]);
check(to_upper_snake_case, "X86_64", expect![[""]]);
}
}
|
