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Introduce #[css(function)] for #[derive(ToCss)]

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Any variant with this attribute gets serialised as a CSS function,
using the variant name as the function name.
This commit is contained in:
Anthony Ramine 2017-06-08 09:36:11 +02:00
parent fd1ab75af9
commit 43a5257a0c
7 changed files with 66 additions and 66 deletions
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69
components/style_derive/to_css.rs
View file

@ -16,24 +16,61 @@ pub fn derive(input: syn::DeriveInput) -> quote::Tokens {
let style = synstructure::BindStyle::Ref.into();
let match_body = synstructure::each_variant(&input, &style, |bindings, variant| {
if bindings.is_empty() {
let identifier = to_css_identifier(variant.ident.as_ref());
return Some(quote! {
let mut identifier = to_css_identifier(variant.ident.as_ref());
let mut expr = if bindings.is_empty() {
quote! {
::std::fmt::Write::write_str(dest, #identifier)
});
}
let (first, rest) = bindings.split_first().expect("unit variants are not yet supported");
where_clause.predicates.push(where_predicate(first.field.ty.clone()));
let mut expr = quote! {
::style_traits::ToCss::to_css(#first, dest)
};
for binding in rest {
where_clause.predicates.push(where_predicate(binding.field.ty.clone()));
expr = quote! {
#expr?;
::std::fmt::Write::write_str(dest, " ")?;
::style_traits::ToCss::to_css(#binding, dest)
}
} else {
let (first, rest) = bindings.split_first().expect("unit variants are not yet supported");
where_clause.predicates.push(where_predicate(first.field.ty.clone()));
let mut expr = quote! {
::style_traits::ToCss::to_css(#first, dest)
};
for binding in rest {
where_clause.predicates.push(where_predicate(binding.field.ty.clone()));
expr = quote! {
#expr?;
::std::fmt::Write::write_str(dest, " ")?;
::style_traits::ToCss::to_css(#binding, dest)
};
}
expr
};
let mut css_attrs = variant.attrs.iter().filter(|attr| attr.name() == "css");
let is_function = css_attrs.next().map_or(false, |attr| {
match attr.value {
syn::MetaItem::List(ref ident, ref items) if ident.as_ref() == "css" => {
let mut nested = items.iter();
let is_function = nested.next().map_or(false, |attr| {
match *attr {
syn::NestedMetaItem::MetaItem(syn::MetaItem::Word(ref ident)) => {
if ident.as_ref() != "function" {
panic!("only `#[css(function)]` is supported for now")
}
true
},
_ => panic!("only `#[css(<ident>)]` is supported for now"),
}
});
if nested.next().is_some() {
panic!("only `#[css()]` or `#[css(<ident>)]` is supported for now")
}
is_function
},
_ => panic!("only `#[css(...)]` is supported for now"),
}
});
if css_attrs.next().is_some() {
panic!("only a single `#[css(...)]` attribute is supported for now");
}
if is_function {
identifier.push_str("(");
expr = quote! {
::std::fmt::Write::write_str(dest, #identifier)?;
#expr?;
::std::fmt::Write::write_str(dest, ")")
}
}
Some(expr)
});