knave 0.14.8

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
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159

use super::open_literals::TypeContext;
use super::type_anchor::{Certainty, TypeAnchor};
use crate::core::{BindingId, TypeExpr, TypeExprKind};
use crate::types::{GenericParam, Type};

type Generics = Vec<usize>;

pub(super) struct GenericPositions {
    parameters: Vec<Generics>,
    result: Generics,
}

impl GenericPositions {
    pub(super) fn of_function(generics: &[GenericParam], function: &Type) -> Option<Self> {
        let Type::Function(_, parameters, result) = function else {
            return None;
        };
        let mentioned = |ty: &Type| Self::indexes(generics, |generic| ty.mentions(generic.id));
        let links: Vec<Generics> = generics
            .iter()
            .map(|generic| {
                generic
                    .bounds
                    .iter()
                    .filter_map(|bound| bound.argument.as_ref())
                    .flat_map(mentioned)
                    .collect()
            })
            .collect();
        let parameters = parameters.iter().map(mentioned).collect();
        Some(Self::linked(parameters, mentioned(result), &links))
    }

    pub(super) fn of_fields<'t>(
        generics: &[GenericParam],
        fields: impl Iterator<Item = &'t Type>,
    ) -> Self {
        Self {
            parameters: fields
                .map(|ty| Self::indexes(generics, |generic| ty.mentions(generic.id)))
                .collect(),
            result: (0..generics.len()).collect(),
        }
    }

    pub(super) fn of_template(type_expr: &TypeExpr) -> Option<Self> {
        let TypeExprKind::Where(binders, body) = type_expr.kind() else {
            return None;
        };
        let TypeExprKind::Function(_, parameters, result) = body.kind() else {
            return None;
        };
        let mentioned = |type_expr: &TypeExpr| {
            Self::indexes(binders, |binder| {
                Self::names_variable(type_expr, binder.variable)
            })
        };
        let links: Vec<Generics> = binders
            .iter()
            .map(|binder| {
                binder
                    .bounds
                    .iter()
                    .filter_map(|bound| bound.argument.as_ref())
                    .flat_map(mentioned)
                    .collect()
            })
            .collect();
        let parameters = parameters.iter().map(mentioned).collect();
        Some(Self::linked(parameters, mentioned(result), &links))
    }

    fn indexes<T>(generics: &[T], mentions: impl Fn(&T) -> bool) -> Generics {
        generics
            .iter()
            .enumerate()
            .filter(|(_, generic)| mentions(generic))
            .map(|(index, _)| index)
            .collect()
    }

    fn names_variable(type_expr: &TypeExpr, variable: BindingId) -> bool {
        matches!(type_expr.kind(), TypeExprKind::Named(binding, _) if *binding == variable)
            || type_expr
                .parts()
                .into_iter()
                .any(|part| Self::names_variable(part, variable))
    }

    fn linked(parameters: Vec<Generics>, result: Generics, links: &[Generics]) -> Self {
        if links.iter().all(Generics::is_empty) {
            return Self { parameters, result };
        }
        let with_links = |generics: &Generics| -> Generics {
            generics
                .iter()
                .flat_map(|generic| Self::linked_to(*generic, links))
                .collect()
        };
        Self {
            parameters: parameters.iter().map(with_links).collect(),
            result: with_links(&result),
        }
    }

    fn linked_to(generic: usize, links: &[Generics]) -> Generics {
        let linking = (0..links.len()).filter(|other| links[*other].contains(&generic));
        std::iter::once(generic)
            .chain(links[generic].iter().copied())
            .chain(linking)
            .collect()
    }

    pub(super) fn contexts(
        &self,
        certainties: &[Certainty],
        outer: TypeContext,
    ) -> Vec<TypeContext> {
        (0..certainties.len())
            .map(|position| {
                if self.is_open(position, certainties, outer) {
                    TypeContext::Unknown
                } else {
                    TypeContext::Known
                }
            })
            .collect()
    }

    fn is_open(&self, position: usize, certainties: &[Certainty], outer: TypeContext) -> bool {
        self.parameters.get(position).is_some_and(|generics| {
            generics
                .iter()
                .any(|generic| !self.is_fixed(*generic, position, certainties, outer))
        })
    }

    fn is_fixed(
        &self,
        generic: usize,
        position: usize,
        certainties: &[Certainty],
        outer: TypeContext,
    ) -> bool {
        let by_result = outer == TypeContext::Known && self.result.contains(&generic);
        by_result || self.anchor(generic, certainties) != Some(position)
    }

    fn anchor(&self, generic: usize, certainties: &[Certainty]) -> Option<usize> {
        TypeAnchor::among(
            self.parameters
                .iter()
                .zip(certainties)
                .enumerate()
                .filter(|(_, (generics, _))| generics.contains(&generic))
                .map(|(position, (_, certainty))| (position, *certainty)),
        )
    }
}