moxy-derive 0.0.3

derive macros for moxy crate
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
138
139
140
141
142
143
144
145

use proc_macro2::TokenStream;
use quote::{format_ident, quote};

use crate::{Render, core::Field, params};

#[derive(Clone, Default)]
pub struct StructSyntax;

impl Render for StructSyntax {
    type Args = params::StructParams;

    fn render(&self, args: Self::Args) -> syn::Result<TokenStream> {
        let ident = &args.input.ident;
        let (impl_generics, type_generics, where_generics) = &args.input.generics.split_for_impl();
        let fields: Vec<_> = args
            .data
            .fields
            .iter()
            .enumerate()
            .map(|(i, field)| Field::parse(i, field))
            .collect::<syn::Result<Vec<_>>>()?;

        let fields: Vec<_> = fields
            .into_iter()
            .filter(|field| field.attrs().exists("set"))
            .collect();

        let methods: Vec<TokenStream> = fields
            .iter()
            .map(|field| -> syn::Result<TokenStream> {
                let fname = field.name();
                let docs = self.render_docs(field);
                let is_option = self.render_option_inner(field).is_some();
                let on_callback = self.render_on_callback(field)?;

                let method_name = match self.render_custom_method_name(field)? {
                    Some(id) => id,
                    None => format_ident!("set_{}", fname.to_string()),
                };

                let setter_ty = if is_option {
                    let inner = self.render_option_inner(field).unwrap();
                    quote!(#inner)
                } else {
                    let ty = field.ty();
                    quote!(#ty)
                };

                let body = if let Some(on_expr) = on_callback {
                    if is_option {
                        quote! {
                            let value: #setter_ty = value.into();
                            self.#fname = ::std::option::Option::Some(#on_expr);
                        }
                    } else {
                        quote! {
                            let value: #setter_ty = value.into();
                            self.#fname = #on_expr;
                        }
                    }
                } else if is_option {
                    quote! {
                        self.#fname = ::std::option::Option::Some(value.into());
                    }
                } else {
                    quote! {
                        self.#fname = value.into();
                    }
                };

                Ok(quote! {
                    #(#docs)*
                    pub fn #method_name<V: ::std::convert::Into<#setter_ty>>(&mut self, value: V) -> &mut Self {
                        #body
                        self
                    }
                })
            })
            .collect::<syn::Result<Vec<_>>>()?;

        Ok(quote! {
            impl #impl_generics #ident #type_generics #where_generics {
                #(#methods)*
            }
        })
    }
}

impl StructSyntax {
    fn render_option_inner<'a>(&self, field: &'a Field) -> Option<&'a syn::Type> {
        let syn::Type::Path(type_path) = field.ty() else {
            return None;
        };
        let segment = type_path.path.segments.last()?;
        if segment.ident != "Option" {
            return None;
        }
        let syn::PathArguments::AngleBracketed(args) = &segment.arguments else {
            return None;
        };
        let syn::GenericArgument::Type(inner) = args.args.first()? else {
            return None;
        };
        Some(inner)
    }

    fn render_custom_method_name(&self, field: &Field) -> syn::Result<Option<proc_macro2::Ident>> {
        let set_args = field.attrs().get("set")?;
        Ok(set_args
            .iter()
            .find_map(|arg| arg.as_attr())
            .and_then(|attr| {
                attr.args().iter().find_map(|a| {
                    if !a.path().is_ident("__value") {
                        return None;
                    }
                    a.as_lit().and_then(|lit| match lit {
                        syn::Lit::Str(s) => Some(format_ident!("{}", s.value())),
                        _ => None,
                    })
                })
            }))
    }

    fn render_on_callback(&self, field: &Field) -> syn::Result<Option<proc_macro2::TokenStream>> {
        let set_args = field.attrs().get("set")?;
        Ok(set_args
            .iter()
            .find_map(|arg| arg.as_attr())
            .and_then(|attr| {
                attr.args()
                    .iter()
                    .find(|a| a.path().is_ident("on"))
                    .and_then(|a| a.as_value_tokens())
            }))
    }

    fn render_docs<'a>(&self, field: &'a Field) -> Vec<&'a syn::Attribute> {
        field
            .raw_attrs()
            .iter()
            .filter(|a| a.path().is_ident("doc"))
            .collect()
    }
}