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
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161

use {KeyboardControllable, Key};
use std::error::Error;
use std::fmt;

/// An error that can occur when parsing DSL
#[derive(Debug, PartialEq, Eq)]
pub enum ParseError {
    /// When a tag doesn't exist.
    /// Example: {+TEST}{-TEST}
    ///            ^^^^   ^^^^
    UnknownTag(String),

    /// When a { is encountered inside a {TAG}.
    /// Example: {+HELLO{WORLD}
    ///                 ^
    UnexpectedOpen,

    /// When a { is never matched with a }.
    /// Example: {+SHIFT}Hello{-SHIFT
    ///                              ^
    UnmatchedOpen,

    /// Opposite of UnmatchedOpen.
    /// Example: +SHIFT}Hello{-SHIFT}
    ///         ^
    UnmatchedClose
}
impl Error for ParseError {
    fn description(&self) -> &str {
        match *self {
            ParseError::UnknownTag(_) => "Unknown tag",
            ParseError::UnexpectedOpen => "Unescaped open bracket ({) found inside tag name",
            ParseError::UnmatchedOpen => "Unmatched open bracket ({). No matching close (})",
            ParseError::UnmatchedClose => "Unmatched close bracket (}). No previous open ({)",
        }
    }
}
impl fmt::Display for ParseError {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        f.write_str(self.description())
    }
}

/// Evaluate the DSL. This tokenizes the input and presses the keys.
pub fn eval<K>(enigo: &mut K, input: &str) -> Result<(), ParseError>
    where K: KeyboardControllable
{
    for token in tokenize(input)? {
        match token {
            Token::Sequence(buffer) => for key in buffer.chars() {
                enigo.key_click(Key::Layout(key));
            },
            Token::Unicode(buffer) => enigo.key_sequence(&buffer),
            Token::KeyUp(key) => enigo.key_up(key),
            Token::KeyDown(key) => enigo.key_down(key)
        }
    }
    Ok(())
}

#[derive(Debug, PartialEq, Eq)]
enum Token {
    Sequence(String),
    Unicode(String),
    KeyUp(Key),
    KeyDown(Key)
}

fn tokenize(input: &str) -> Result<Vec<Token>, ParseError> {
    let mut unicode = false;

    let mut tokens = Vec::new();
    let mut buffer = String::new();
    let mut iter = input.chars().peekable();

    fn flush(tokens: &mut Vec<Token>, buffer: String, unicode: bool) {
        if !buffer.is_empty() {
            if unicode {
                tokens.push(Token::Unicode(buffer));
            } else {
                tokens.push(Token::Sequence(buffer));
            }
        }
    }

    while let Some(c) = iter.next() {
        if c == '{' {
            match iter.next() {
                Some('{') => buffer.push('{'),
                Some(mut c) => {
                    flush(&mut tokens, buffer, unicode);
                    buffer = String::new();

                    let mut tag = String::new();
                    loop {
                        tag.push(c);
                        match iter.next() {
                            Some('{') => match iter.peek() {
                                Some(&'{') => { iter.next(); c = '{' },
                                _ => return Err(ParseError::UnexpectedOpen)
                            },
                            Some('}') => match iter.peek() {
                                Some(&'}') => { iter.next(); c = '}' },
                                _ => break
                            },
                            Some(new) => c = new,
                            None => return Err(ParseError::UnmatchedOpen)
                        }
                    }
                    match &*tag {
                        "+UNICODE" => unicode = true,
                        "-UNICODE" => unicode = false,
                        "+SHIFT" => tokens.push(Token::KeyDown(Key::Shift)),
                        "-SHIFT" => tokens.push(Token::KeyUp(Key::Shift)),
                        "+CTRL" => tokens.push(Token::KeyDown(Key::Control)),
                        "-CTRL" => tokens.push(Token::KeyUp(Key::Control)),
                        _ => return Err(ParseError::UnknownTag(tag)),
                    }
                },
                None => return Err(ParseError::UnmatchedOpen)
            }
        } else if c == '}' {
            match iter.next() {
                Some('}') => buffer.push('}'),
                _ => return Err(ParseError::UnmatchedClose)
            }
        } else {
            buffer.push(c);
        }
    }

    flush(&mut tokens, buffer, unicode);

    Ok(tokens)
}

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

    #[test]
    fn success() {
        assert_eq!(
            tokenize("{{Hello World!}} {+CTRL}hi{-CTRL}"),
            Ok(vec![Token::Sequence("{Hello World!} ".into()), Token::KeyDown(Key::Control),
            Token::Sequence("hi".into()), Token::KeyUp(Key::Control)])
        );
    }
    #[test]
    fn unexpected_open() {
        assert_eq!(tokenize("{hello{}world}"), Err(ParseError::UnexpectedOpen));
    }
    #[test]
    fn unmatched_open() {
        assert_eq!(tokenize("{this is going to fail"), Err(ParseError::UnmatchedOpen));
    }
    #[test]
    fn unmatched_close() {
        assert_eq!(tokenize("{+CTRL}{{this}} is going to fail}"), Err(ParseError::UnmatchedClose));
    }
}