miette_derive/
related.rs

1use proc_macro2::TokenStream;
2use quote::{format_ident, quote};
3use syn::spanned::Spanned;
4
5use crate::{
6    diagnostic::{DiagnosticConcreteArgs, DiagnosticDef},
7    forward::WhichFn,
8    utils::{display_pat_members, gen_all_variants_with},
9};
10
11pub struct Related(syn::Member);
12
13impl Related {
14    pub(crate) fn from_fields(fields: &syn::Fields) -> syn::Result<Option<Self>> {
15        match fields {
16            syn::Fields::Named(named) => Self::from_fields_vec(named.named.iter().collect()),
17            syn::Fields::Unnamed(unnamed) => {
18                Self::from_fields_vec(unnamed.unnamed.iter().collect())
19            }
20            syn::Fields::Unit => Ok(None),
21        }
22    }
23
24    fn from_fields_vec(fields: Vec<&syn::Field>) -> syn::Result<Option<Self>> {
25        for (i, field) in fields.iter().enumerate() {
26            for attr in &field.attrs {
27                if attr.path().is_ident("related") {
28                    let related = if let Some(ident) = field.ident.clone() {
29                        syn::Member::Named(ident)
30                    } else {
31                        syn::Member::Unnamed(syn::Index {
32                            index: i as u32,
33                            span: field.span(),
34                        })
35                    };
36                    return Ok(Some(Related(related)));
37                }
38            }
39        }
40        Ok(None)
41    }
42
43    pub(crate) fn gen_enum(variants: &[DiagnosticDef]) -> Option<TokenStream> {
44        gen_all_variants_with(
45            variants,
46            WhichFn::Related,
47            |ident, fields, DiagnosticConcreteArgs { related, .. }| {
48                let (display_pat, _display_members) = display_pat_members(fields);
49                related.as_ref().map(|related| {
50                    let rel = match &related.0 {
51                        syn::Member::Named(ident) => ident.clone(),
52                        syn::Member::Unnamed(syn::Index { index, .. }) => {
53                            format_ident!("_{}", index)
54                        }
55                    };
56                    quote! {
57                        Self::#ident #display_pat => {
58                            std::option::Option::Some(std::boxed::Box::new(
59                                #rel.iter().map(|x| -> &(dyn miette::Diagnostic) { &*x })
60                            ))
61                        }
62                    }
63                })
64            },
65        )
66    }
67
68    pub(crate) fn gen_struct(&self) -> Option<TokenStream> {
69        let rel = &self.0;
70        Some(quote! {
71            fn related<'a>(&'a self) -> std::option::Option<std::boxed::Box<dyn std::iter::Iterator<Item = &'a dyn miette::Diagnostic> + 'a>> {
72                use ::core::borrow::Borrow;
73                std::option::Option::Some(std::boxed::Box::new(
74                        self.#rel.iter().map(|x| -> &(dyn miette::Diagnostic) { &*x.borrow() })
75                ))
76            }
77        })
78    }
79}
miette_derive/related.rs

miette_derive/
related.rs
