arraygen 0.3.2

Derive macro for generating arrays from struct fields.
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

use crate::DECL_FN_NAME;
use std::collections::HashMap;
use syn::parse::{Parse, ParseStream, Result};
use syn::token;
use syn::{braced, Error, Generics, Ident, Token, Visibility, WhereClause};

use crate::parse_attribute::parse_inner_attributes;
use crate::parse_gen_array::{parse_gen_arrays, GenArray};
use crate::parse_in_array::{
    parse_in_array_fields, InArrayElement, InArrayElementKind, InArrayField,
};
use crate::types::ty_inferred_by;

pub struct DeriveArraygen {
    pub gen_arrays: HashMap<Ident, GenArray>,
    pub vis: Visibility,
    pub struct_name: Ident,
    pub generics: Generics,
}

impl Parse for DeriveArraygen {
    fn parse(input: ParseStream) -> Result<Self> {
        let mut gen_arrays = input.call(parse_gen_arrays)?;
        let vis = input.parse::<Visibility>()?;

        let lookahead = input.lookahead1();
        if !lookahead.peek(Token![struct]) {
            return Err(input.error("derive 'Arraygen' should only be used with braced structs"));
        }

        let _ = input.parse::<Token![struct]>()?;
        let struct_name = input.parse::<Ident>()?;
        let generics = input.parse::<Generics>()?;
        let where_clause = parse_struct(input, &mut gen_arrays)?;

        Ok(DeriveArraygen {
            gen_arrays,
            vis,
            struct_name,
            generics: Generics {
                where_clause,
                ..generics
            },
        })
    }
}

pub fn parse_struct(
    input: ParseStream,
    gen_arrays: &mut HashMap<Ident, GenArray>,
) -> Result<Option<WhereClause>> {
    let mut lookahead = input.lookahead1();
    let mut where_clause = None;
    if lookahead.peek(Token![where]) {
        where_clause = Some(input.parse()?);
        lookahead = input.lookahead1();
    }

    if lookahead.peek(token::Brace) {
        parse_braced_struct(input, gen_arrays)?;
        Ok(where_clause)
    } else {
        Err(input.error("derive 'Arraygen' should only be used with braced structs"))
    }
}

pub(crate) fn parse_braced_struct(
    input: ParseStream,
    gen_arrays: &mut HashMap<Ident, GenArray>,
) -> Result<()> {
    let content;
    let _ = braced!(content in input);
    parse_inner_attributes(&content)?;
    for iaf in content
        .parse_terminated::<InArrayField, Token![,]>(parse_in_array_fields)?
        .into_iter()
    {
        for (_, ga) in gen_arrays.iter_mut() {
            for implicit_ty in ga.implicit_select_all_tys.iter() {
                if ty_inferred_by(&iaf.ty, implicit_ty) {
                    ga.fields.push(InArrayElement {
                        ident: iaf.ident.clone(),
                        ty: iaf.ty.clone(),
                        cast: ga.implicit_select_all_decorator.cast.clone(),
                        kind: InArrayElementKind::Implicit,
                    });
                }
            }
        }
        for attr in iaf.attrs.iter() {
            for entry in attr.entries.iter() {
                if let Some(ga) = gen_arrays.get_mut(&entry.ident) {
                    let iae = ga.fields.iter().find(|iae| iae.ident == iaf.ident);
                    if matches!(iae, Some(iae) if iae.kind != InArrayElementKind::Implicit || (iae.kind == InArrayElementKind::Implicit && !entry.decorator.override_implicit))
                    {
                        return Err(Error::new_spanned(
                            entry.ident.clone(),
                            format!(
                                "Field '{}' is already included in {} method '{}'",
                                iaf.ident.to_string(),
                                DECL_FN_NAME,
                                entry.ident.to_string()
                            ),
                        ));
                    } else {
                        if let Some(ident) = iae.map(|iae| iae.ident.clone()) {
                            ga.fields.retain(|field| field.ident != ident);
                        }

                        ga.fields.push(InArrayElement {
                            ident: iaf.ident.clone(),
                            ty: iaf.ty.clone(),
                            cast: entry.decorator.cast.clone(),
                            kind: InArrayElementKind::InArray,
                        });
                    }
                } else {
                    return Err(Error::new_spanned(
                        entry.ident.clone(),
                        format!(
                            "{} method '{}' not present but used by field '{}'",
                            DECL_FN_NAME,
                            entry.ident.to_string(),
                            iaf.ident.to_string()
                        ),
                    ));
                }
            }
        }
    }
    Ok(())
}