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
|
use syntax::Expr;
use {Error, Result};
/// Returns a new expression that is guaranteed to never match the given
/// ASCII character.
///
/// If the expression contains the literal byte, then an error is returned.
///
/// If `byte` is not an ASCII character (i.e., greater than `0x7F`), then this
/// function panics.
pub fn remove(expr: Expr, byte: u8) -> Result<Expr> {
use syntax::Expr::*;
assert!(byte <= 0x7F);
let chr = byte as char;
assert!(chr.len_utf8() == 1);
Ok(match expr {
Literal { chars, casei } => {
if chars.iter().position(|&c| c == chr).is_some() {
return Err(Error::LiteralNotAllowed(chr));
}
Literal { chars: chars, casei: casei }
}
LiteralBytes { bytes, casei } => {
if bytes.iter().position(|&b| b == byte).is_some() {
return Err(Error::LiteralNotAllowed(chr));
}
LiteralBytes { bytes: bytes, casei: casei }
}
AnyChar => AnyCharNoNL,
AnyByte => AnyByteNoNL,
Class(mut cls) => {
cls.remove(chr);
Class(cls)
}
ClassBytes(mut cls) => {
cls.remove(byte);
ClassBytes(cls)
}
Group { e, i, name } => {
Group {
e: Box::new(try!(remove(*e, byte))),
i: i,
name: name,
}
}
Repeat { e, r, greedy } => {
Repeat {
e: Box::new(try!(remove(*e, byte))),
r: r,
greedy: greedy,
}
}
Concat(exprs) => {
Concat(try!(
exprs.into_iter().map(|e| remove(e, byte)).collect()))
}
Alternate(exprs) => {
Alternate(try!(
exprs.into_iter().map(|e| remove(e, byte)).collect()))
}
e => e,
})
}
|
