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Use darling in style_derive

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This allows use to handle #[css] in a way simpler fashion.
This commit is contained in:
Anthony Ramine 2017-08-24 00:48:59 +02:00
parent 49a5ceca9b
commit 17d97cf87b
5 changed files with 63 additions and 42 deletions
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1
components/style_derive/Cargo.toml
View file

@ -10,6 +10,7 @@ path = "lib.rs"
proc-macro = true
[dependencies]
darling = "0.2"
quote = "0.3.15"
syn = { version = "0.11", features = ["visit"] }
synstructure = "0.5.2"

11
components/style_derive/cg.rs
View file

@ -2,6 +2,7 @@
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
use darling::FromVariant;
use quote::Tokens;
use std::borrow::Cow;
use std::iter;
@ -136,6 +137,16 @@ where
}
}
pub fn parse_variant_attrs<A>(variant: &Variant) -> A
where
A: FromVariant,
{
match A::from_variant(variant) {
Ok(attrs) => attrs,
Err(e) => panic!("failed to parse attributes: {}", e),
}
}
pub fn ref_pattern<'a>(
name: &Ident,
variant: &'a Variant,

1
components/style_derive/lib.rs
View file

@ -2,6 +2,7 @@
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#[macro_use] extern crate darling;
extern crate proc_macro;
#[macro_use] extern crate quote;
extern crate syn;

52
components/style_derive/to_css.rs
View file

@ -16,47 +16,8 @@ pub fn derive(input: syn::DeriveInput) -> quote::Tokens {
let style = synstructure::BindStyle::Ref.into();
let match_body = synstructure::each_variant(&input, &style, |bindings, variant| {
let mut identifier = to_css_identifier(variant.ident.as_ref());
let mut css_attrs = variant.attrs.iter().filter(|attr| attr.name() == "css");
let (is_function, use_comma) = css_attrs.next().map_or((false, false), |attr| {
match attr.value {
syn::MetaItem::List(ref ident, ref items) if ident.as_ref() == "css" => {
let mut nested = items.iter();
let mut is_function = false;
let mut use_comma = false;
for attr in nested.by_ref() {
match *attr {
syn::NestedMetaItem::MetaItem(syn::MetaItem::Word(ref ident)) => {
match ident.as_ref() {
"function" => {
if is_function {
panic!("repeated `#[css(function)]` attribute");
}
is_function = true;
},
"comma" => {
if use_comma {
panic!("repeated `#[css(comma)]` attribute");
}
use_comma = true;
},
_ => panic!("only `#[css(function | comma)]` is supported for now"),
}
},
_ => 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, use_comma)
},
_ => panic!("only `#[css(...)]` is supported for now"),
}
});
if css_attrs.next().is_some() {
panic!("only a single `#[css(...)]` attribute is supported for now");
}
let separator = if use_comma { ", " } else { " " };
let css_attrs = cg::parse_variant_attrs::<CssAttrs>(variant);
let separator = if css_attrs.comma { ", " } else { " " };
let mut expr = if !bindings.is_empty() {
let mut expr = quote! {};
for binding in bindings {
@ -80,7 +41,7 @@ pub fn derive(input: syn::DeriveInput) -> quote::Tokens {
::std::fmt::Write::write_str(dest, #identifier)
}
};
if is_function {
if css_attrs.function {
identifier.push_str("(");
expr = quote! {
::std::fmt::Write::write_str(dest, #identifier)?;
@ -107,6 +68,13 @@ pub fn derive(input: syn::DeriveInput) -> quote::Tokens {
}
}
#[derive(Default, FromVariant)]
#[darling(attributes(css), default)]
struct CssAttrs {
function: bool,
comma: bool,
}
/// Transforms "FooBar" to "foo-bar".
///
/// If the first Camel segment is "Moz" or "Webkit", the result string