87 lines
2.6 KiB
Rust
87 lines
2.6 KiB
Rust
use proc_macro::TokenStream;
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use convert_case::{Case, Casing};
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use quote::{quote, ToTokens, TokenStreamExt};
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use syn::__private::TokenStream2;
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use syn::parse::{Parse, ParseStream};
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use syn::punctuated::Punctuated;
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use syn::{braced, parse_macro_input, Ident, Token};
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#[proc_macro]
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pub fn impl_extension_attributes(input: TokenStream) -> TokenStream {
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let input = parse_macro_input!(input as ImplExtensionAttributes);
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input.to_token_stream().into()
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}
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struct ImplExtensionAttributes {
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is_element: bool,
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name: Ident,
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attrs: Punctuated<Ident, Token![,]>,
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}
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impl Parse for ImplExtensionAttributes {
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fn parse(input: ParseStream) -> syn::Result<Self> {
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let content;
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let element: Ident = input.parse()?;
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let name = input.parse()?;
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braced!(content in input);
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let attrs = content.parse_terminated(Ident::parse, Token![,])?;
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Ok(ImplExtensionAttributes {
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is_element: element.to_string() == "ELEMENT",
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name,
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attrs,
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})
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}
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}
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impl ToTokens for ImplExtensionAttributes {
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fn to_tokens(&self, tokens: &mut TokenStream2) {
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let name = &self.name;
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let camel_name = name.to_string().to_case(Case::UpperCamel);
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let impl_name = Ident::new(format!("{}Impl", &camel_name).as_str(), name.span());
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let extension_name = Ident::new(format!("{}Extension", &camel_name).as_str(), name.span());
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let marker_name = Ident::new(
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format!("Extended{}Marker", &camel_name).as_str(),
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name.span(),
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);
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if !self.is_element {
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tokens.append_all(quote! {
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struct #impl_name;
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impl #name for #impl_name {}
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});
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}
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let defs = self.attrs.iter().map(|ident| {
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quote! {
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fn #ident(self, value: impl IntoAttributeValue<'a>) -> Self;
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}
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});
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let impls = self.attrs.iter().map(|ident| {
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let d = if self.is_element {
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quote! { #name::#ident }
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} else {
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quote! { <#impl_name as #name>::#ident }
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};
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quote! {
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fn #ident(self, value: impl IntoAttributeValue<'a>) -> Self {
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let d = #d;
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self.push_attribute(d.0, d.1, value, d.2)
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}
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}
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});
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tokens.append_all(quote! {
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pub trait #marker_name {}
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pub trait #extension_name<'a> {
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#(#defs)*
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}
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impl<'a, T> #extension_name<'a> for T where T: HasAttributesBox<'a, T> + #marker_name {
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#(#impls)*
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}
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});
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}
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}
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