uu_env 0.4.0

env ~ (uutils) set each NAME to VALUE in the environment and run COMMAND
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

// This file is part of the uutils coreutils package.
//
// For the full copyright and license information, please view the LICENSE
// file that was distributed with this source code.

use std::ops::Range;

use crate::EnvError;
use crate::{native_int_str::NativeIntStr, string_parser::StringParser};

pub struct VariableParser<'a, 'b> {
    pub parser: &'b mut StringParser<'a>,
}

impl<'a> VariableParser<'a, '_> {
    fn get_current_char(&self) -> Option<char> {
        self.parser.peek().ok()
    }

    fn check_variable_name_start(&self) -> Result<(), EnvError> {
        if let Some(c) = self.get_current_char() {
            if c.is_ascii_digit() {
                return Err(EnvError::EnvParsingOfVariableUnexpectedNumber(
                    self.parser.get_peek_position(),
                    c.to_string(),
                ));
            }
        }
        Ok(())
    }

    fn skip_one(&mut self) -> Result<(), EnvError> {
        self.parser.consume_chunk()?;
        Ok(())
    }

    fn parse_braced_variable_name(
        &mut self,
    ) -> Result<(&'a NativeIntStr, Option<&'a NativeIntStr>), EnvError> {
        let pos_start = self.parser.get_peek_position();

        self.check_variable_name_start()?;

        let (varname_end, default_end);
        loop {
            match self.get_current_char() {
                None => {
                    return Err(EnvError::EnvParsingOfVariableMissingClosingBrace(
                        self.parser.get_peek_position(),
                    ));
                }
                Some(c) if !c.is_ascii() || c.is_ascii_alphanumeric() || c == '_' => {
                    self.skip_one()?;
                }
                Some(':') => {
                    varname_end = self.parser.get_peek_position();
                    loop {
                        match self.get_current_char() {
                            None => {
                                return Err(
                                    EnvError::EnvParsingOfVariableMissingClosingBraceAfterValue(
                                        self.parser.get_peek_position(),
                                    ),
                                );
                            }
                            Some('}') => {
                                default_end = Some(self.parser.get_peek_position());
                                self.skip_one()?;
                                break;
                            }
                            Some(_) => {
                                self.skip_one()?;
                            }
                        }
                    }
                    break;
                }
                Some('}') => {
                    varname_end = self.parser.get_peek_position();
                    default_end = None;
                    self.skip_one()?;
                    break;
                }
                Some(c) => {
                    return Err(EnvError::EnvParsingOfVariableExceptedBraceOrColon(
                        self.parser.get_peek_position(),
                        c.to_string(),
                    ));
                }
            }
        }

        let default_opt = if let Some(default_end) = default_end {
            Some(self.parser.substring(&Range {
                start: varname_end + 1,
                end: default_end,
            }))
        } else {
            None
        };

        let varname = self.parser.substring(&Range {
            start: pos_start,
            end: varname_end,
        });

        Ok((varname, default_opt))
    }

    fn parse_unbraced_variable_name(&mut self) -> Result<&'a NativeIntStr, EnvError> {
        let pos_start = self.parser.get_peek_position();

        self.check_variable_name_start()?;

        loop {
            match self.get_current_char() {
                None => break,
                Some(c) if c.is_ascii_alphanumeric() || c == '_' => {
                    self.skip_one()?;
                }
                Some(_) => break,
            }
        }

        let pos_end = self.parser.get_peek_position();

        if pos_end == pos_start {
            return Err(EnvError::EnvParsingOfMissingVariable(pos_start));
        }

        let varname = self.parser.substring(&Range {
            start: pos_start,
            end: pos_end,
        });

        Ok(varname)
    }

    pub fn parse_variable(
        &mut self,
    ) -> Result<(&'a NativeIntStr, Option<&'a NativeIntStr>), EnvError> {
        self.skip_one()?;

        let (name, default) = match self.get_current_char() {
            None => {
                return Err(EnvError::EnvParsingOfMissingVariable(
                    self.parser.get_peek_position(),
                ));
            }
            Some('{') => {
                self.skip_one()?;
                self.parse_braced_variable_name()?
            }
            Some(_) => (self.parse_unbraced_variable_name()?, None),
        };

        Ok((name, default))
    }
}