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
|
use onig::{Captures, Regex, Replacer};
use std::borrow::Cow;
/// A string, with `$1` refering to the first capture group.
struct Dollarified<'a>(&'a str);
/// Capture Reference to Captured String
///
/// Tries to convert a refernece to a capture to the captured text. If
/// the reference isn't a valid numeric capture group then no text is
/// returned.
fn capture_str<'t>(caps: &'t Captures, cap_ref: &str) -> Option<&'t str> {
cap_ref.parse::<usize>().ok().and_then(|p| caps.at(p))
}
impl<'a> Replacer for Dollarified<'a> {
fn reg_replace(&mut self, caps: &Captures) -> Cow<str> {
let mut replacement = String::new();
let mut pattern = self.0;
while !pattern.is_empty() {
if let Some(position) = pattern.find('$') {
// push up to the replacement
replacement.push_str(&pattern[..position]);
pattern = &pattern[position + 1..];
// find the end of the capture reference
let ref_end = pattern
.find(|c| !char::is_numeric(c))
.unwrap_or(pattern.len());
// push the capture from this capture reference
if let Some(cap) = capture_str(caps, &pattern[..ref_end]) {
replacement.push_str(cap);
pattern = &pattern[ref_end..];
} else {
replacement.push('$');
}
} else {
// no replacements left
replacement.push_str(pattern);
break;
}
}
replacement.into()
}
}
fn test_with(replacement: &str) {
let re = Regex::new(r"(\w+) (\w+)").unwrap();
let hay = "well (hello world) to you!";
println!(
"/{}/{}/ -> {}",
&hay,
&replacement,
re.replace(hay, Dollarified(replacement))
);
}
fn main() {
test_with("$2 $1");
test_with("($2 $1)");
test_with("|$2|$1|");
test_with("|$0|$2$1");
test_with("$$$");
test_with("$$$3");
test_with("$$2$3");
test_with("Literal replacement");
}
|
