lexer-rs 0.0.4

Lexical anaylzer framework for context-free text parsing into tokens
Documentation 
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

//a Imports
use crate::UserPosn;

//a LineColumn
//tp LineColumn
/// A line and column within a text stream
///
/// This provides the [UserPosn] trait, which provides methods to
/// retrieve the line and column values of the state. This can be used
/// as the 'State' type for a lexer, allowing the line and column of
/// tokens to be tracked, and hence lexer tokens can be formmatted in
/// a user-friendly fashion.
#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
pub struct LineColumn {
    line: usize,
    column: usize,
}

//ip Default for LineColumn
impl std::default::Default for LineColumn {
    fn default() -> Self {
        Self { line: 1, column: 1 }
    }
}

//ip Display for LineColumn
impl std::fmt::Display for LineColumn {
    fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> {
        write!(fmt, "line {} column {}", self.line, self.column)
    }
}

//ip UserPosn for LineColumn
impl UserPosn for LineColumn {
    fn line(&self) -> usize {
        self.line
    }

    fn column(&self) -> usize {
        self.column
    }
    fn advance_cols(mut self, _: usize, num_chars: usize) -> Self {
        self.column += num_chars;
        self
    }
    fn advance_line(mut self, _: usize) -> Self {
        self.column = 1;
        self.line += 1;
        self
    }
    fn error_fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> {
        write!(fmt, "line {} column {}", self.line, self.column)
    }
}