4 releases
0.2.1 | May 24, 2019 |
---|---|
0.2.0 | May 24, 2019 |
0.1.1 | Mar 30, 2019 |
0.1.0 | Mar 30, 2019 |
#2493 in Parser implementations
21 downloads per month
Used in 2 crates
16KB
217 lines
text-reader
Rust string character reader.
Usage
[dependencies]
text-reader = "0.2"
Examples
TextReader
use text_reader::TextReader;
#[test]
fn test_while() {
let mut reader = TextReader::new("華文\ndef");
while reader.has_next() {
let position = reader.position();
match reader.next() {
Some(ch) => match position {
0 => assert_eq!('華', ch),
1 => assert_eq!('文', ch),
2 => assert_eq!('\n', ch),
3 => assert_eq!('d', ch),
4 => assert_eq!('e', ch),
5 => assert_eq!('f', ch),
_ => {}
},
None => panic!("None")
}
}
}
TextReader and Detector
#[test]
fn test_detector() {
let text = r#"
{"type": "typeA", "name": "Earth", "continent": ["Asia", "Europe"]}
"#;
let mut reader = TextReader::new(text);
let mut rets = Vec::new();
while reader.has_next() {
match reader.next() {
Some('"') => {
let mut detector = reader.detector();
rets.push('"');
if detector.next_text("type").yes() {
detector.rollback();
rets.push('t');
}
continue;
},
Some(ch) => {
rets.push(ch);
continue;
}
None => {}
}
}
let ret = rets.iter().collect::<String>();
println!("{}", ret);
}
more
Analysis
use text_reader::TextReader;
#[test]
fn test_stat() {
let mut reader = TextReader::new("abc\ndef");
println!("{:?}", reader);
reader.next();
println!("{:?}", reader);
reader.back();
println!("{:?}", reader);
let line_text = reader.this_line();
println!("{:?}", line_text);
let position = reader.position();
println!("{:?}", position);
println!("{:?}", reader);
reader.next();
reader.next();
reader.next();
let line = reader.line(); // 1
assert_eq!(1, line);
println!("{:?}", reader);
reader.next();
let line = reader.line(); // 2
assert_eq!(2, line);
println!("{:?}", reader);
}
When create a TextReader TextReader::new("abc\ndef")
, TextReader status is:
TextReader { len: 7, text: ['a', 'b', 'c', '\n', 'd', 'e', 'f'], position: 0, line: 1, cursor: 0 }
next
And then, read next character let ch = reader.next()
, ch
will return Some('a')
; TextReader status:
TextReader { len: 7, text: ['a', 'b', 'c', '\n', 'd', 'e', 'f'], position: 1, line: 1, cursor: 1 }
peek
peek function not change status, only get current character let ch = reader.peek()
TextReader { len: 7, text: ['a', 'b', 'c', '\n', 'd', 'e', 'f'], position: 1, line: 1, cursor: 1 }
back
Back will change TextReader to previous status. return TextReader reference. reader.back()
.
TextReader { len: 7, text: ['a', 'b', 'c', '\n', 'd', 'e', 'f'], position: 0, line: 1, cursor: 0 }
this_line
this line return current line text, not change TextReader status. let line_text = reader.this_line()
.
TextReader { len: 7, text: ['a', 'b', 'c', '\n', 'd', 'e', 'f'], position: 0, line: 1, cursor: 0 }
line_text is Some("abc")
position
position function return TextReader position value. the num of character position. let position = reader.position()
position is 0
TextReader { len: 7, text: ['a', 'b', 'c', '\n', 'd', 'e', 'f'], position: 0, line: 1, cursor: 0 }
line
return current line number, split of \n
.
reader.next();
reader.next();
reader.next();
let line = reader.line(); // 1
// TextReader { len: 7, text: ['a', 'b', 'c', '\n', 'd', 'e', 'f'], position: 3, line: 1, cursor: 3 }
reader.next();
let line = reader.line(); // 2
// TextReader { len: 7, text: ['a', 'b', 'c', '\n', 'd', 'e', 'f'], position: 4, line: 2, cursor: 0 }
cursor
position of line. starting from 0. and change to 0 when it encounters \n
has_next
has next character. can be used with while. or determine if the last character