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

use super::Value;
use crate::Node;

#[derive(Clone, Copy)]
/// Wrapper around the tape that allows interacting with it via a `Array`-like API.
pub struct Array<'tape, 'input>(pub(super) &'tape [Node<'input>]);

pub struct ArrayIter<'tape, 'input>(&'tape [Node<'input>]);

// value_trait::Array for
impl<'tape, 'input> Array<'tape, 'input>
where
    'input: 'tape,
{
    /// FIXME: docs

    #[must_use]
    pub fn get(&self, mut idx: usize) -> Option<Value<'tape, 'input>> {
        let mut offset = 1;
        while idx > 0 {
            offset += self.0.get(offset)?.count();
            idx -= 1;
        }
        let count = self.0.get(offset)?.count();
        Some(Value(&self.0[offset..offset + count]))
    }
    /// FIXME: docs
    #[must_use]
    pub fn iter<'i>(&'i self) -> ArrayIter<'tape, 'input> {
        ArrayIter(&self.0[1..])
    }

    /// FIXME: docs
    /// # Panics
    /// if the tape is not an array
    #[must_use]
    pub fn len(&self) -> usize {
        if let Some(Node::Array { len, .. }) = self.0.first() {
            *len
        } else {
            panic!("invalid tape array")
        }
    }
    /// FIXME: docs
    #[must_use]
    pub fn is_empty(&self) -> bool {
        self.len() == 0
    }
}

impl<'tape, 'input> Iterator for ArrayIter<'tape, 'input> {
    type Item = Value<'tape, 'input>;

    fn next(&mut self) -> Option<Self::Item> {
        let (head, tail) = self.0.split_at(self.0.first()?.count());
        self.0 = tail;
        Some(Value(head))
    }
}

#[cfg(test)]
mod test {
    use crate::to_tape;
    use value_trait::base::ValueAsScalar;

    #[test]
    fn get_ints() -> crate::Result<()> {
        let mut input = b"[1,2,3,4]".to_vec();
        let t = to_tape(input.as_mut_slice())?;
        let v = t.as_value();
        let a = v.as_array().expect("is an array");
        assert_eq!(a.get(0).and_then(|v| v.as_u64()), Some(1));
        assert_eq!(a.get(1).and_then(|v| v.as_u64()), Some(2));
        assert_eq!(a.get(2).and_then(|v| v.as_u64()), Some(3));
        assert_eq!(a.get(3).and_then(|v| v.as_u64()), Some(4));
        assert_eq!(a.get(4), None);
        Ok(())
    }

    #[test]
    fn get_nested() -> crate::Result<()> {
        let mut input = b"[1,[2,3],4]".to_vec();
        let t = to_tape(input.as_mut_slice())?;
        let v = t.as_value();
        let a = v.as_array().expect("is an array");
        assert_eq!(a.get(0).and_then(|v| v.as_u64()), Some(1));
        let a1 = a.get(1).expect("has first element");
        let a2 = a1.as_array().expect("is an array");
        assert_eq!(a2.get(0).and_then(|v| v.as_u64()), Some(2));
        assert_eq!(a2.get(1).and_then(|v| v.as_u64()), Some(3));
        assert_eq!(a.get(2).and_then(|v| v.as_u64()), Some(4));
        assert_eq!(a.get(3), None);
        Ok(())
    }

    #[test]
    fn iter() -> crate::Result<()> {
        let mut input = b"[1,2,3,4]".to_vec();
        let t = to_tape(input.as_mut_slice())?;
        let v = t.as_value();
        let a = v.as_array().expect("is an array");
        let v = a
            .iter()
            .map(|v| v.as_u8().expect("integer"))
            .collect::<Vec<_>>();

        assert_eq!(v, vec![1, 2, 3, 4]);

        Ok(())
    }
    #[test]
    fn iter_container() -> crate::Result<()> {
        let mut input = b"[1,[2,3],4]".to_vec();
        let t = to_tape(input.as_mut_slice())?;
        let v = t.as_value();
        let a = v.as_array().expect("is an array");
        let v = a.iter().map(|v| v.as_u8()).collect::<Vec<_>>();

        assert_eq!(v, vec![Some(1), None, Some(4)]);

        Ok(())
    }
}