simple_c_lexer/
simple_c_lexer.rs

1use codespan_reporting::diagnostic::*;
2use orecc_front::{chars, Codebase, TokenReader};
3
4pub fn main() {
5    let args = std::env::args().collect::<Vec<_>>();
6    if args.len() != 2 {
7        eprintln!("Usage: cargo run --example simple_c_lexer -- sample.c");
8        return;
9    }
10
11    let code = std::fs::read_to_string(&args[1]).unwrap();
12    let mut codebase = Codebase::new();
13    let key = codebase.add(args[1].clone(), code);
14
15    let mut reader = TokenReader::new(codebase.get(key).unwrap().source().clone());
16    while let Some(char) = reader.next_char() {
17        if chars::is_digit(char) {
18            // * Number
19            println!("Number {}", reader.next_token(chars::is_digit, char));
20        } else if chars::is_ident_start(char) {
21            // * Identifier
22            println!(
23                "Ident {}",
24                reader.next_token(chars::is_ident_continue, char)
25            );
26        } else if char == '"' {
27            // * String
28            let mut string = String::new();
29            loop {
30                match reader.next_char() {
31                    // Escape sequences
32                    Some('\\') => match reader.next_char() {
33                        Some('n') => string.push('\n'),
34                        Some(char) => string.push(char),
35                        None => codebase.emit( // Technically won't happen
36                            Diagnostic::error()
37                                .with_message("expected escape code")
38                                .with_labels(vec![Label::primary(
39                                    key,
40                                    reader.cursor..reader.cursor + 1,
41                                )
42                                .with_message("here")]),
43                        ),
44                    },
45
46                    // Quote
47                    Some('"') => break,
48
49                    // Char
50                    Some(char) if char != '\n' => string.push(char),
51                    _ => {
52                        codebase.emit(
53                            Diagnostic::error()
54                                .with_message("unterminated string")
55                                .with_labels(vec![Label::primary(
56                                    key,
57                                    reader.cursor..reader.cursor + 1,
58                                )
59                                .with_message("here")]),
60                        );
61                        break;
62                    }
63                }
64            }
65            println!("String {:?}", string);
66        } else if ['(', ')', '{', '}', ';'].contains(&char) {
67            // * Operator
68            println!("Operator {}", char);
69        }
70    }
71}
simple_c_lexer/simple_c_lexer.rs

simple_c_lexer/
simple_c_lexer.rs
