cco 0.2.0

cascading configuration
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

use super::*;
use crate::err::*;
use crate::eval::*;
use crate::value::*;

#[derive(Debug, Clone)]
pub struct MapperExpr {
    pub source: Index,
    pub key_name: Option<Index>,
    pub value_name: Index,
    pub output: Output,
}

impl Expr for MapperExpr {
    fn resolve(
        &self,
        index: Index,
        evaluation: &mut dyn ExprEvaluator,
    ) -> Result<ValueOrReference, ErrorKind> {
        let mut required = vec![self.value_name, self.source];
        if let Some(key_name) = self.key_name {
            required.push(key_name);
        }

        evaluation.ensure_resolved(required)?;

        let value_name_value = evaluation.get_value(self.value_name)?;
        let value_name = value_name_value
            .as_string()
            .ok_or(ErrorKind::TypeNotAllowed {
                item: index,
                expr: self.value_name,
                expected: ValueKind::String,
                actual: value_name_value.kind(),
            })?;

        let contexts: Vec<Index> = match evaluation.get_value(self.source)? {
            Value::List(items) => items
                .into_iter()
                .map(|value| {
                    let value_expr = evaluation.create(Expression::literal(LiteralExpr { value }));
                    evaluation.create(Expression::map(MapExpr {
                        items: vec![(MapKey::Literal(value_name.to_string()), value_expr)],
                    }))
                })
                .collect(),
            Value::Map(items) => items
                .into_iter()
                .map(|(key, value)| {
                    let value_expr = evaluation.create(Expression::literal(LiteralExpr { value }));

                    let mut items = vec![(MapKey::Literal(value_name.to_string()), value_expr)];

                    if let Some(key_name) = self.key_name {
                        let key_expr = evaluation
                            .create(Expression::literal(LiteralExpr { value: key.into() }));
                        items.push((MapKey::Expression(key_name), key_expr));
                    }

                    evaluation.create(Expression::map(MapExpr { items }))
                })
                .collect(),
            other => {
                let expected = if self.key_name.is_some() {
                    ValueKind::Object
                } else {
                    ValueKind::Array
                };
                return Err(ErrorKind::ForLoopTypeMismatch {
                    index,
                    expected,
                    actual: other.kind(),
                })?;
            }
        };

        match self.output {
            Output::List { expr } => {
                let expressions = contexts
                    .into_iter()
                    .map(|ctx| evaluation.clone_with_context(expr, ctx))
                    .collect();

                let referenced =
                    evaluation.create(Expression::list(ListExpr { items: expressions }));

                Ok(ValueOrReference::Reference(referenced))
            }
            Output::Map {
                key_expr,
                value_expr,
            } => {
                let expressions: Vec<(Index, Index)> = contexts
                    .into_iter()
                    .map(|ctx| {
                        (
                            evaluation.clone_with_context(key_expr, ctx),
                            evaluation.clone_with_context(value_expr, ctx),
                        )
                    })
                    .collect();

                let referenced = evaluation.create(Expression::map(MapExpr::from(expressions)));
                Ok(ValueOrReference::Reference(referenced))
            }
            Output::StringConcat { expr } => {
                let expressions = contexts
                    .into_iter()
                    .map(|ctx| evaluation.clone_with_context(expr, ctx))
                    .collect();

                let referenced = evaluation.create(Expression::concat_string(ConcatStringExpr {
                    parts: expressions,
                }));
                Ok(ValueOrReference::Reference(referenced))
            }
        }
    }

    fn traverse(
        &self,
        _evaluation: &dyn ExprEvaluator,
        expression: Index,
        _name: &Indexer,
    ) -> Result<Option<ValueOrReference>, ErrorKind> {
        Err(ErrorKind::DependenciesNotSatisfied {
            indices: vec![expression],
        })
    }
}

#[derive(Debug, Clone, Copy)]
pub enum Output {
    List { expr: Index },
    Map { key_expr: Index, value_expr: Index },
    StringConcat { expr: Index },
}