titleformat-rs 0.2.0

A foobar2000 titleformat parser for rust
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
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
102
103
104
105

use crate::environment::value_string;
use crate::environment::Value;
use crate::types::Error;
use crate::types::Error::*;

use unicode_segmentation::UnicodeSegmentation;

pub fn upper(args: Vec<Value>) -> Result<Value, Error> {
    if args.len() != 1 {
        return Err(InvalidNativeFunctionArgs(String::from("upper"), args.len()));
    }

    Ok(value_string(
        args[0].val.to_uppercase().as_str(),
        args[0].cond,
    ))
}

pub fn lower(args: Vec<Value>) -> Result<Value, Error> {
    if args.len() != 1 {
        return Err(InvalidNativeFunctionArgs(String::from("lower"), args.len()));
    }

    Ok(value_string(
        args[0].val.to_lowercase().as_str(),
        args[0].cond,
    ))
}

/*
 * $firstalphachar(text,nonalpha="#")
 *
 * Returns the first character of text. If text is not an alphabetic character nonalpha is returned instead.
 */
pub fn firstalphachar(args: Vec<Value>) -> Result<Value, Error> {
    let missing = match args.len() {
        1 => String::from("#"),
        2 => args[1].val.clone(),
        _ => return Err(InvalidNativeFunctionArgs(String::from("lower"), args.len())),
    };

    let s = args[0].val.as_str();
    let c = UnicodeSegmentation::graphemes(s, true)
        .next()
        .map_or(missing.clone(), |seg| {
            seg.chars().next().map_or(missing.clone(), |c| {
                if c.is_alphabetic() {
                    c.to_string()
                } else {
                    missing
                }
            })
        });

    Ok(value_string(&c, args[0].cond))
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn wrong_n_arguments() {
        assert_eq!(
            upper(vec![]).err().unwrap(),
            InvalidNativeFunctionArgs(String::from("upper"), 0)
        );
        assert_eq!(
            lower(vec![]).err().unwrap(),
            InvalidNativeFunctionArgs(String::from("lower"), 0)
        );
    }

    #[test]
    fn test_upper() {
        assert_eq!(
            upper(vec![value_string("AbcD", true)]).unwrap(),
            value_string("ABCD", true)
        );
    }

    #[test]
    fn test_lower() {
        assert_eq!(
            lower(vec![value_string("AbcD", true)]).unwrap(),
            value_string("abcd", true)
        );
    }

    #[test]
    fn test_firstalphachar() {
        assert_eq!(
            firstalphachar(vec![value_string("AbcD", true)]).unwrap(),
            value_string("A", true)
        );
        assert_eq!(
            firstalphachar(vec![value_string("1", true)]).unwrap(),
            value_string("#", true)
        );
        assert_eq!(
            firstalphachar(vec![value_string("1", true), value_string("@", true)]).unwrap(),
            value_string("@", true)
        );
    }
}