icydb-model-macros 0.215.7

Procedural macros for IcyDB application models
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

//! Module: imp::from
//! Responsibility: generated implementation tokens.
//! Does not own: runtime trait semantics.
//! Boundary: parsed nodes to impl tokens.

use crate::prelude::*;

///
/// FromTrait
/// to and from ::View types is handled with a blanket impl
///

pub struct FromTrait {}

///
/// List
///

impl Imp<List> for FromTrait {
    fn strategy(node: &List) -> Option<TraitStrategy> {
        let item = &node.item.type_expr();
        Some(vec_collection_from_strategy(
            node.def(),
            item,
            quote!(entries.into_iter().map(Into::into).collect()),
            None,
        ))
    }
}

///
/// Map
///

impl Imp<Map> for FromTrait {
    fn strategy(node: &Map) -> Option<TraitStrategy> {
        let key = &node.key.type_expr();
        let value = &node.value.type_expr();
        Some(map_from_strategy(node.def(), key, value))
    }
}

///
/// Newtype
///

impl Imp<Newtype> for FromTrait {
    fn strategy(node: &Newtype) -> Option<TraitStrategy> {
        let item = &node.item.type_expr();
        Some(newtype_from_strategy(node.def(), item))
    }
}

///
/// Set
///

impl Imp<Set> for FromTrait {
    fn strategy(node: &Set) -> Option<TraitStrategy> {
        let item = &node.item.type_expr();
        Some(vec_collection_from_strategy(
            node.def(),
            item,
            quote!(entries.into_iter().map(Into::into).collect()),
            Some(quote!(#item: ::std::cmp::Ord)),
        ))
    }
}

fn vec_collection_from_strategy(
    def: &Def,
    item: &TokenStream,
    body: TokenStream,
    extra_constraint: Option<TokenStream>,
) -> TraitStrategy {
    let mut implementor = Implementor::new(def, TraitKind::From)
        .set_tokens(vec_collection_from_tokens(body))
        .add_impl_constraint(quote!(I: Into<#item>))
        .add_impl_generic(quote!(I))
        .add_trait_generic(quote!(Vec<I>));

    if let Some(extra_constraint) = extra_constraint {
        implementor = implementor.add_impl_constraint(extra_constraint);
    }

    TraitStrategy::from_impl(implementor.to_token_stream())
}

fn vec_collection_from_tokens(body: TokenStream) -> TokenStream {
    quote! {
        fn from(entries: Vec<I>) -> Self {
            Self(#body)
        }
    }
}

fn map_from_strategy(def: &Def, key: &TokenStream, value: &TokenStream) -> TraitStrategy {
    let tokens = Implementor::new(def, TraitKind::From)
        .set_tokens(quote! {
            fn from(entries: Vec<(IK, IV)>) -> Self {
                Self(
                    entries
                        .into_iter()
                        .map(|(key, value)| (key.into(), value.into()))
                        .collect(),
                )
            }
        })
        .add_impl_constraint(quote!(IK: Into<#key>))
        .add_impl_constraint(quote!(IV: Into<#value>))
        .add_impl_constraint(quote!(#key: ::std::cmp::Ord))
        .add_impl_generic(quote!(IK))
        .add_impl_generic(quote!(IV))
        .add_trait_generic(quote!(Vec<(IK, IV)>))
        .to_token_stream();

    TraitStrategy::from_impl(tokens)
}

fn newtype_from_strategy(def: &Def, item: &TokenStream) -> TraitStrategy {
    let tokens = Implementor::new(def, TraitKind::From)
        .set_tokens(quote! {
            fn from(t: T) -> Self {
                Self(t.into())
            }
        })
        .add_impl_constraint(quote!(T: Into<#item>))
        .add_impl_generic(quote!(T))
        .add_trait_generic(quote!(T))
        .to_token_stream();

    TraitStrategy::from_impl(tokens)
}