1 //! This example shows an example of how to parse an escaped string. The
2 //! rules for the string are similar to JSON and rust. A string is:
3 //!
4 //! - Enclosed by double quotes
5 //! - Can contain any raw unescaped code point besides \ and "
6 //! - Matches the following escape sequences: \b, \f, \n, \r, \t, \", \\, \/
7 //! - Matches code points like Rust: \u{XXXX}, where XXXX can be up to 6
8 //! hex characters
9 //! - an escape followed by whitespace consumes all whitespace between the
10 //! escape and the next non-whitespace character
11
12 #![cfg(feature = "alloc")]
13
14 mod parser;
15
16 use winnow::prelude::*;
17
main() -> Result<(), lexopt::Error>18 fn main() -> Result<(), lexopt::Error> {
19 let args = Args::parse()?;
20
21 let data = args.input.as_deref().unwrap_or("\"abc\"");
22 let result = parser::parse_string::<()>.parse(data);
23 match result {
24 Ok(data) => println!("{}", data),
25 Err(err) => println!("{:?}", err),
26 }
27
28 Ok(())
29 }
30
31 #[derive(Default)]
32 struct Args {
33 input: Option<String>,
34 }
35
36 impl Args {
parse() -> Result<Self, lexopt::Error>37 fn parse() -> Result<Self, lexopt::Error> {
38 use lexopt::prelude::*;
39
40 let mut res = Args::default();
41
42 let mut args = lexopt::Parser::from_env();
43 while let Some(arg) = args.next()? {
44 match arg {
45 Value(input) => {
46 res.input = Some(input.string()?);
47 }
48 _ => return Err(arg.unexpected()),
49 }
50 }
51 Ok(res)
52 }
53 }
54
55 #[test]
simple()56 fn simple() {
57 let data = "\"abc\"";
58 let result = parser::parse_string::<()>.parse(data);
59 assert_eq!(result, Ok(String::from("abc")));
60 }
61
62 #[test]
escaped()63 fn escaped() {
64 let data = "\"tab:\\tafter tab, newline:\\nnew line, quote: \\\", emoji: \\u{1F602}, newline:\\nescaped whitespace: \\ abc\"";
65 let result = parser::parse_string::<()>.parse(data);
66 assert_eq!(
67 result,
68 Ok(String::from("tab:\tafter tab, newline:\nnew line, quote: \", emoji: ��, newline:\nescaped whitespace: abc"))
69 );
70 }
71