knave 0.14.4

A Lisp programming language for humans and agents that infers types and ownership and compiles to readable 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

use super::constructor::Constructor;
use super::cover_pattern::CoverPattern;
use crate::types::Type;

#[derive(Clone, Copy)]
pub(super) struct Query<'q> {
    patterns: &'q [CoverPattern],
    types: &'q [Type],
}

pub(super) struct ExpandedQuery {
    patterns: Vec<CoverPattern>,
    types: Vec<Type>,
}

impl<'q> Query<'q> {
    pub(super) fn new(patterns: &'q [CoverPattern], types: &'q [Type]) -> Self {
        Self { patterns, types }
    }

    pub(super) fn is_empty(&self) -> bool {
        self.patterns.is_empty()
    }

    pub(super) fn first_pattern(&self) -> &'q CoverPattern {
        &self.patterns[0]
    }

    pub(super) fn first_type(&self) -> &'q Type {
        &self.types[0]
    }

    pub(super) fn rest(&self) -> Self {
        Self::new(&self.patterns[1..], &self.types[1..])
    }

    pub(super) fn expanded(
        &self,
        constructor: &Constructor,
        arguments: &[CoverPattern],
    ) -> ExpandedQuery {
        ExpandedQuery {
            patterns: [arguments, &self.patterns[1..]].concat(),
            types: constructor.columns_with(&self.types[1..]),
        }
    }
}

impl ExpandedQuery {
    pub(super) fn query(&self) -> Query<'_> {
        Query::new(&self.patterns, &self.types)
    }
}

#[cfg(test)]
mod tests {
    use super::Query;
    use crate::core::{Literal, PrimitiveType};
    use crate::types::Type;
    use crate::types::coverage::constructor::Constructor;
    use crate::types::coverage::constructor_tag::ConstructorTag;
    use crate::types::coverage::cover_pattern::CoverPattern;

    struct QueryFixture {
        patterns: Vec<CoverPattern>,
        types: Vec<Type>,
    }

    impl QueryFixture {
        fn new() -> Self {
            Self {
                patterns: vec![
                    CoverPattern::Wild,
                    CoverPattern::Literal(Literal::Bool(false)),
                ],
                types: vec![Self::text(), Self::boolean()],
            }
        }

        fn query(&self) -> Query<'_> {
            Query::new(&self.patterns, &self.types)
        }

        fn text() -> Type {
            Type::Primitive(PrimitiveType::String)
        }

        fn boolean() -> Type {
            Type::Primitive(PrimitiveType::Bool)
        }

        fn unit() -> Type {
            Type::Primitive(PrimitiveType::Unit)
        }
    }

    #[test]
    fn a_query_with_no_columns_is_empty() {
        assert!(Query::new(&[], &[]).is_empty());
    }

    #[test]
    fn its_first_column_gives_the_first_pattern_and_type() {
        let fixture = QueryFixture::new();
        assert!(matches!(
            fixture.query().first_pattern(),
            CoverPattern::Wild
        ));
        assert_eq!(fixture.query().first_type(), &QueryFixture::text());
    }

    #[test]
    fn its_rest_drops_the_first_column() {
        let fixture = QueryFixture::new();
        let rest = fixture.query().rest();
        assert!(matches!(
            rest.first_pattern(),
            CoverPattern::Literal(Literal::Bool(false))
        ));
        assert_eq!(rest.first_type(), &QueryFixture::boolean());
        assert!(rest.rest().is_empty());
    }

    #[test]
    fn expanding_puts_the_constructor_columns_in_place_of_the_first() {
        let fixture = QueryFixture::new();
        let constructor = Constructor::new(ConstructorTag::Bool(true), vec![QueryFixture::unit()]);
        let expanded = fixture
            .query()
            .expanded(&constructor, &[CoverPattern::Wild]);
        let query = expanded.query();
        assert_eq!(query.first_type(), &QueryFixture::unit());
        assert!(matches!(
            query.rest().first_pattern(),
            CoverPattern::Literal(Literal::Bool(false))
        ));
        assert_eq!(query.rest().first_type(), &QueryFixture::boolean());
    }
}