lunar-lib 0.9.0

Common utilities for lunar applications
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

use std::fmt::{self, Write};

use crate::formatter::{FormatTable, Render, template::TemplateItem};

#[derive(Debug, Clone, Default, PartialEq, Eq)]
pub(super) struct Condition<'a> {
    pub tokens: Vec<ConditionalToken<'a>>,
}

impl Condition<'_> {
    pub(super) fn solve(&self, format_table: &FormatTable) -> bool {
        enum Operator {
            Or(bool),
            And(bool),
            Nor(bool),
            Nand(bool),
        }

        let mut operators = Vec::new();
        let mut condition = false;
        let mut inverted = false;
        let mut can_invert = true;

        let mut iter = self.tokens.iter().peekable();
        while let Some(token) = iter.next() {
            match token {
                ConditionalToken::Arg(arg) => {
                    let mut state = !arg.render(format_table).is_empty();

                    while let Some(ConditionalToken::Arg(peek_arg)) = iter.peek() {
                        if !state {
                            state = !peek_arg.render(format_table).is_empty();
                        }
                        iter.next();
                    }

                    condition = conditional_invert(state, inverted);
                    inverted = false;
                    can_invert = false;
                }
                ConditionalToken::Or => {
                    if let Some(ConditionalToken::Or) = iter.peek() {
                        operators.push(Operator::Or(condition));
                        iter.next();
                        can_invert = true;
                    } else {
                        condition = true;
                        can_invert = false;
                    }
                }
                ConditionalToken::And => {
                    if let Some(ConditionalToken::And) = iter.peek() {
                        operators.push(Operator::And(condition));
                        iter.next();
                        can_invert = true;
                    } else {
                        condition = true;
                        can_invert = false;
                    }
                }
                ConditionalToken::Not => match iter.peek() {
                    Some(ConditionalToken::Or) => {
                        operators.push(Operator::Nor(condition));
                        iter.next();
                        can_invert = true;
                    }
                    Some(ConditionalToken::And) => {
                        operators.push(Operator::Nand(condition));
                        iter.next();
                        can_invert = true;
                    }
                    _ if can_invert => inverted = !inverted,
                    _ => {
                        condition = true;
                        can_invert = false;
                    }
                },
            }
        }

        condition = conditional_invert(condition, inverted);
        operators.reverse();
        for operator in operators {
            condition = match operator {
                Operator::Or(lhs) => lhs || condition,
                Operator::And(lhs) => lhs && condition,
                Operator::Nor(lhs) => !(lhs || condition),
                Operator::Nand(lhs) => !(lhs && condition),
            }
        }

        condition
    }
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub(super) enum ConditionalToken<'a> {
    Arg(TemplateItem<'a>),
    Or,
    And,
    Not,
}

impl ConditionalToken<'_> {
    pub fn to_str(&self) -> &'static str {
        match self {
            ConditionalToken::Or => "|",
            ConditionalToken::And => "&",
            ConditionalToken::Not => "!",
            ConditionalToken::Arg(_) => unreachable!(
                "Attempted to turn ConditionalToken::Arg into a &str. This should never happen"
            ),
        }
    }
}

fn conditional_invert(condition: bool, invert: bool) -> bool {
    if invert { !condition } else { condition }
}

impl fmt::Display for ConditionalToken<'_> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            ConditionalToken::Or => f.write_char('|'),
            ConditionalToken::And => f.write_char('&'),
            ConditionalToken::Not => f.write_char('!'),
            ConditionalToken::Arg(arg) => arg.fmt(f),
        }
    }
}

impl fmt::Display for Condition<'_> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        for token in &self.tokens {
            token.fmt(f)?;
        }
        Ok(())
    }
}