rweb_macros/
util.rs

1use pmutil::{synom_ext::FromSpan, ToTokensExt};
2use proc_macro2::Span;
3use quote::quote;
4use syn::{punctuated::Pair, *};
5
6pub fn call_site<T: FromSpan>() -> T {
7    T::from_span(Span::call_site())
8}
9
10/// Extension trait for `ItemImpl` (impl block).
11pub trait ItemImplExt {
12    /// Instead of
13    ///
14    /// ```rust,ignore
15    /// let (impl_generics, ty_generics, where_clause) = input.generics.split_for_impl();
16    ///
17    /// let item: Item = Quote::new(def_site::<Span>())
18    ///     .quote_with(smart_quote!(
19    /// Vars {
20    /// Type: type_name,
21    /// impl_generics,
22    /// ty_generics,
23    /// where_clause,
24    /// },
25    /// {
26    /// impl impl_generics ::swc_common::AstNode for Type ty_generics
27    /// where_clause {}
28    /// }
29    /// )).parse();
30    /// ```
31    ///
32    /// You can use this like
33    ///
34    /// ```rust,ignore
35    // let item = Quote::new(def_site::<Span>())
36    ///     .quote_with(smart_quote!(Vars { Type: type_name }, {
37    ///         impl ::swc_common::AstNode for Type {}
38    ///     }))
39    ///     .parse::<ItemImpl>()
40    ///     .with_generics(input.generics);
41    /// ```
42    fn with_generics(self, generics: Generics) -> Self;
43}
44
45impl ItemImplExt for ItemImpl {
46    fn with_generics(mut self, mut generics: Generics) -> Self {
47        // TODO: Check conflicting name
48
49        let need_new_punct = !generics.params.empty_or_trailing();
50        if need_new_punct {
51            generics.params.push_punct(call_site());
52        }
53
54        // Respan
55        if let Some(t) = generics.lt_token {
56            self.generics.lt_token = Some(t)
57        }
58        if let Some(t) = generics.gt_token {
59            self.generics.gt_token = Some(t)
60        }
61
62        let ty = self.self_ty;
63
64        // Handle generics defined on struct, enum, or union.
65        let mut item: ItemImpl = {
66            let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
67            let item = if let Some((ref polarity, ref path, ref for_token)) = self.trait_ {
68                quote! {
69                    impl #impl_generics #polarity #path #for_token #ty #ty_generics #where_clause {}
70                }
71            } else {
72                quote! {
73                    impl #impl_generics #ty #ty_generics #where_clause {}
74
75                }
76            };
77            parse(item.dump().into())
78                .unwrap_or_else(|err| panic!("with_generics failed: {}\n{}", err, item.dump()))
79        };
80
81        // Handle generics added by proc-macro.
82        item.generics
83            .params
84            .extend(self.generics.params.into_pairs());
85        match self.generics.where_clause {
86            Some(WhereClause {
87                ref mut predicates, ..
88            }) => predicates.extend(
89                generics
90                    .where_clause
91                    .into_iter()
92                    .flat_map(|wc| wc.predicates.into_pairs()),
93            ),
94            ref mut opt @ None => *opt = generics.where_clause,
95        }
96
97        ItemImpl {
98            attrs: self.attrs,
99            defaultness: self.defaultness,
100            unsafety: self.unsafety,
101            impl_token: self.impl_token,
102            brace_token: self.brace_token,
103            items: self.items,
104            ..item
105        }
106    }
107}
108
109pub trait PairExt<T, P>: Sized + Into<Pair<T, P>> {
110    fn map_item<F, NewItem>(self, op: F) -> Pair<NewItem, P>
111    where
112        F: FnOnce(T) -> NewItem,
113    {
114        match self.into() {
115            Pair::Punctuated(t, p) => Pair::Punctuated(op(t), p),
116            Pair::End(t) => Pair::End(op(t)),
117        }
118    }
119}
120
121impl<T, P> PairExt<T, P> for Pair<T, P> {}
rweb_macros/util.rs

rweb_macros/
util.rs
