yosh 0.2.7

A POSIX-compliant shell implemented in 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
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
162
163
164
165
166
167
168
169
170
171

use std::fmt;

#[derive(Debug, Clone, PartialEq)]
pub struct ShellError {
    pub kind: ShellErrorKind,
    pub message: String,
    pub location: Option<SourceLocation>,
}

#[derive(Debug, Clone, Copy, PartialEq)]
pub struct SourceLocation {
    pub line: usize,
    pub column: usize,
}

#[derive(Debug, Clone, PartialEq)]
pub enum ShellErrorKind {
    Parse(ParseErrorKind),
    Expansion(ExpansionErrorKind),
    Runtime(RuntimeErrorKind),
}

#[derive(Debug, Clone, Copy, PartialEq)]
pub enum ParseErrorKind {
    UnterminatedSingleQuote,
    UnterminatedDoubleQuote,
    UnterminatedCommandSub,
    UnterminatedArithSub,
    UnterminatedParamExpansion,
    UnterminatedBacktick,
    UnterminatedDollarSingleQuote,
    UnexpectedToken,
    #[allow(dead_code)] // matched in parse_status; will be constructed by parser enhancements
    UnexpectedEof,
    InvalidRedirect,
    #[allow(dead_code)] // will be constructed by function definition parsing
    InvalidFunctionName,
    InvalidHereDoc,
}

#[derive(Debug, Clone, Copy, PartialEq)]
#[allow(dead_code)]
pub enum ExpansionErrorKind {
    DivisionByZero,
    UnsetVariable,
    ParameterError,
    InvalidArithmetic,
}

#[derive(Debug, Clone, Copy, PartialEq)]
pub enum RuntimeErrorKind {
    CommandNotFound,
    PermissionDenied,
    RedirectFailed,
    ReadonlyVariable,
    InvalidOption,
    InvalidArgument,
    IoError,
    ExecFailed,
    #[allow(dead_code)] // reserved for future trap-handler error reporting
    TrapError,
    JobControlError,
}

impl fmt::Display for ShellError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match &self.location {
            Some(loc) => write!(f, "yosh: line {}: {}", loc.line, self.message),
            None => write!(f, "yosh: {}", self.message),
        }
    }
}

impl std::error::Error for ShellError {}

impl ShellError {
    pub fn parse(
        kind: ParseErrorKind,
        line: usize,
        column: usize,
        message: impl Into<String>,
    ) -> Self {
        Self {
            kind: ShellErrorKind::Parse(kind),
            message: message.into(),
            location: Some(SourceLocation { line, column }),
        }
    }

    pub fn expansion(kind: ExpansionErrorKind, message: impl Into<String>) -> Self {
        Self {
            kind: ShellErrorKind::Expansion(kind),
            message: message.into(),
            location: None,
        }
    }

    pub fn runtime(kind: RuntimeErrorKind, message: impl Into<String>) -> Self {
        Self {
            kind: ShellErrorKind::Runtime(kind),
            message: message.into(),
            location: None,
        }
    }

    /// Map this error to an appropriate POSIX exit code.
    pub fn exit_code(&self) -> i32 {
        match &self.kind {
            ShellErrorKind::Parse(_) => 2,
            ShellErrorKind::Expansion(_) => 1,
            ShellErrorKind::Runtime(r) => match r {
                RuntimeErrorKind::CommandNotFound => 127,
                RuntimeErrorKind::PermissionDenied | RuntimeErrorKind::ExecFailed => 126,
                RuntimeErrorKind::InvalidOption | RuntimeErrorKind::InvalidArgument => 2,
                _ => 1,
            },
        }
    }
}

pub type Result<T> = std::result::Result<T, ShellError>;

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

    #[test]
    fn test_error_display_with_location() {
        let err = ShellError::parse(ParseErrorKind::UnexpectedToken, 5, 10, "unexpected ')'");
        assert_eq!(err.to_string(), "yosh: line 5: unexpected ')'");
    }

    #[test]
    fn test_error_display_without_location() {
        let err = ShellError::runtime(RuntimeErrorKind::CommandNotFound, "foo: not found");
        assert_eq!(err.to_string(), "yosh: foo: not found");
    }

    #[test]
    fn test_runtime_error_new_variants() {
        let err = ShellError::runtime(RuntimeErrorKind::InvalidArgument, "bad arg");
        assert_eq!(err.to_string(), "yosh: bad arg");

        let err = ShellError::runtime(RuntimeErrorKind::IoError, "read failed");
        assert_eq!(err.to_string(), "yosh: read failed");
    }

    #[test]
    fn test_exit_code_mapping() {
        assert_eq!(
            ShellError::runtime(RuntimeErrorKind::CommandNotFound, "x").exit_code(),
            127
        );
        assert_eq!(
            ShellError::runtime(RuntimeErrorKind::PermissionDenied, "x").exit_code(),
            126
        );
        assert_eq!(
            ShellError::runtime(RuntimeErrorKind::InvalidArgument, "x").exit_code(),
            2
        );
        assert_eq!(
            ShellError::runtime(RuntimeErrorKind::IoError, "x").exit_code(),
            1
        );
        assert_eq!(
            ShellError::runtime(RuntimeErrorKind::RedirectFailed, "x").exit_code(),
            1
        );
    }
}