knave-expand 0.14.21

The reading, scoping and expansion stages of knave
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

use std::rc::Rc;

use crate::core::Namespace;
use crate::source::{SourceId, Span};

#[derive(Default)]
pub(super) struct RecordedInputs {
    inputs: Vec<Span>,
    bound: Vec<BoundName>,
    loaded: Vec<LoadedModule>,
    registering: Option<Span>,
}

#[derive(Clone, Debug, PartialEq, Eq)]
pub struct BoundName {
    pub name: Rc<str>,
    pub namespace: Namespace,
    pub span: Span,
}

#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub struct LoadedModule {
    pub source: SourceId,
    pub input: Span,
}

impl BoundName {
    pub fn names_the_same(&self, other: &BoundName) -> bool {
        self.name == other.name && self.namespace == other.namespace
    }
}

impl RecordedInputs {
    pub(super) fn new(inputs: Vec<Span>) -> Self {
        Self {
            inputs,
            ..Self::default()
        }
    }

    pub(super) fn note_bound(&mut self, span: Span, name: impl FnOnce() -> Option<BoundName>) {
        if self.surrounds(span) {
            self.bound.extend(name());
        }
    }

    pub(super) fn enter(&mut self, written: Span) -> Option<Span> {
        let outer = self.registering;
        if self.inputs.contains(&written) {
            self.registering = Some(written);
        }
        outer
    }

    pub(super) fn leave(&mut self, outer: Option<Span>) {
        self.registering = outer;
    }

    pub(super) fn note_loaded(&mut self, source: SourceId) {
        if let Some(input) = self.registering {
            self.loaded.push(LoadedModule { source, input });
        }
    }

    pub(super) fn bound_by(&self, span: Span) -> Vec<BoundName> {
        self.bound
            .iter()
            .filter(|name| span.contains(name.span))
            .cloned()
            .collect()
    }

    pub(super) fn loaded(&self) -> &[LoadedModule] {
        &self.loaded
    }

    fn surrounds(&self, span: Span) -> bool {
        self.inputs.iter().any(|input| input.contains(span))
    }
}

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

    struct RecordFixture;

    impl RecordFixture {
        const INPUT: usize = 0;
        const OUTSIDE: usize = 20;

        fn span(start: usize) -> Span {
            Span::new(SourceId::new(0), start..start + 1)
        }

        fn name(span: Span) -> Option<BoundName> {
            Some(BoundName {
                name: "bound".into(),
                namespace: Namespace::Value,
                span,
            })
        }

        fn recording() -> RecordedInputs {
            RecordedInputs::new(vec![Self::span(Self::INPUT)])
        }
    }

    #[test]
    fn a_name_bound_outside_every_input_is_not_recorded() {
        let mut recorded = RecordFixture::recording();
        let outside = RecordFixture::span(RecordFixture::OUTSIDE);
        recorded.note_bound(outside, || RecordFixture::name(outside));
        let covering = Span::new(SourceId::new(0), 0..RecordFixture::OUTSIDE + 1);
        assert!(recorded.bound_by(covering).is_empty());
    }

    #[test]
    fn a_module_loaded_while_an_input_registers_belongs_to_the_input() {
        let mut recorded = RecordFixture::recording();
        let input = RecordFixture::span(RecordFixture::INPUT);
        let outer = recorded.enter(input);
        let nested = recorded.enter(RecordFixture::span(RecordFixture::OUTSIDE));
        recorded.note_loaded(SourceId::new(1));
        recorded.leave(nested);
        recorded.leave(outer);
        recorded.note_loaded(SourceId::new(2));
        assert_eq!(
            recorded.loaded(),
            [LoadedModule {
                source: SourceId::new(1),
                input
            }]
        );
    }
}