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
use std::iter::Peekable;
use std::str::Chars;
pub struct BufferedInput<'a> {
buffer: String,
chars: Peekable<Chars<'a>>,
}
impl<'a> BufferedInput<'a> {
pub(crate) fn new(input: &'a str) -> BufferedInput<'a> {
BufferedInput {
buffer: String::new(),
chars: input.chars().peekable(),
}
}
pub fn take_buffer(&mut self) -> String {
let buffer = self.buffer.clone();
self.buffer.clear();
buffer
}
#[inline(always)]
pub fn peek(&mut self) -> Option<char> {
self.chars.peek().map(|&c| c)
}
#[inline(always)]
pub fn skip(&mut self) -> Option<char> {
self.chars.next()
}
pub fn skip_if<P: Fn(&char) -> bool>(&mut self, predicate: P) -> Option<char> {
if let Some(c) = self.peek() {
if predicate(&c) {
self.skip();
return Some(c);
}
}
None
}
pub fn skip_while<P: Fn(&char) -> bool>(&mut self, predicate: P) {
while let Some(_) = self.skip_if(&predicate) {}
}
pub fn accept(&mut self) -> Option<char> {
if let Some(c) = self.chars.next() {
self.buffer.push(c);
Some(c)
} else {
None
}
}
pub fn accept_if<P: Fn(&char) -> bool>(&mut self, predicate: P) -> Option<char> {
if let Some(c) = self.peek() {
if predicate(&c) {
self.accept().unwrap();
return Some(c)
}
}
None
}
pub fn accept_while<P: Fn(&char) -> bool>(&mut self, predicate: P) {
while let Some(_) = self.accept_if(&predicate) {}
}
pub fn accept_or<P: Fn(&char) -> bool, T>(&mut self, predicate: P, ok: T, default: T) -> T {
if let Some(_) = self.accept_if(predicate) {
ok
} else {
default
}
}
#[inline]
pub fn skip_whitespace(&mut self) {
self.skip_while(char::is_ascii_whitespace);
}
}