Introduce #[animation(constant)] for the Animate trait

This allows us to handle fields that should be the same during animations.
This commit is contained in:
Anthony Ramine 2017-08-25 23:51:12 +02:00
parent e49dbc4dfa
commit eaf2f1ec33
5 changed files with 59 additions and 52 deletions

View file

@ -28,9 +28,30 @@ pub fn derive(input: syn::DeriveInput) -> quote::Tokens {
let mut computations = quote!();
let iter = result_info.iter().zip(this_info.iter().zip(&other_info));
computations.append_all(iter.map(|(result, (this, other))| {
where_clause.add_trait_bound(this.field.ty.clone());
quote! {
let #result = ::values::animated::Animate::animate(#this, #other, procedure)?;
let field_attrs = cg::parse_field_attrs::<AnimateFieldAttrs>(&result.field);
if field_attrs.constant {
if cg::is_parameterized(&result.field.ty, where_clause.params) {
where_clause.inner.predicates.push(cg::where_predicate(
result.field.ty.clone(),
&["std", "cmp", "PartialEq"],
));
where_clause.inner.predicates.push(cg::where_predicate(
result.field.ty.clone(),
&["std", "clone", "Clone"],
));
}
quote! {
if #this != #other {
return Err(());
}
let #result = ::std::clone::Clone::clone(#this);
}
} else {
where_clause.add_trait_bound(result.field.ty.clone());
quote! {
let #result =
::values::animated::Animate::animate(#this, #other, procedure)?;
}
}
}));
Some(quote! {
@ -67,3 +88,9 @@ pub fn derive(input: syn::DeriveInput) -> quote::Tokens {
pub struct AnimateAttrs {
pub error: bool,
}
#[derive(Default, FromField)]
#[darling(attributes(animation), default)]
pub struct AnimateFieldAttrs {
pub constant: bool,
}

View file

@ -2,12 +2,12 @@
* 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 darling::{FromField, FromVariant};
use quote::{ToTokens, Tokens};
use std::borrow::Cow;
use std::collections::HashSet;
use std::iter;
use syn::{self, AngleBracketedParameterData, Body, DeriveInput, Ident};
use syn::{self, AngleBracketedParameterData, Body, DeriveInput, Field, Ident};
use syn::{ImplGenerics, Path, PathParameters, PathSegment, PolyTraitRef};
use syn::{QSelf, TraitBoundModifier, Ty, TyGenerics, TyParam, TyParamBound};
use syn::{Variant, WhereBoundPredicate, WherePredicate};
@ -15,15 +15,15 @@ use syn::visit::{self, Visitor};
use synstructure::{self, BindOpts, BindStyle, BindingInfo};
pub struct WhereClause<'input, 'path> {
clause: syn::WhereClause,
params: &'input [TyParam],
pub inner: syn::WhereClause,
pub params: &'input [TyParam],
trait_path: &'path [&'path str],
bounded_types: HashSet<Ty>,
}
impl<'input, 'path> ToTokens for WhereClause<'input, 'path> {
fn to_tokens(&self, tokens: &mut Tokens) {
self.clause.to_tokens(tokens);
self.inner.to_tokens(tokens);
}
}
@ -31,7 +31,7 @@ impl<'input, 'path> WhereClause<'input, 'path> {
pub fn add_trait_bound(&mut self, ty: Ty) {
if is_parameterized(&ty, self.params) && !self.bounded_types.contains(&ty) {
self.bounded_types.insert(ty.clone());
self.clause.predicates.push(where_predicate(ty, self.trait_path));
self.inner.predicates.push(where_predicate(ty, self.trait_path));
}
}
}
@ -116,13 +116,23 @@ where
}
}
pub fn parse_field_attrs<A>(field: &Field) -> A
where
A: FromField,
{
match A::from_field(field) {
Ok(attrs) => attrs,
Err(e) => panic!("failed to parse field attributes: {}", e),
}
}
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),
Err(e) => panic!("failed to parse variant attributes: {}", e),
}
}
@ -144,7 +154,7 @@ pub fn trait_parts<'input, 'path>(
) -> (ImplGenerics<'input>, TyGenerics<'input>, WhereClause<'input, 'path>) {
let (impl_generics, ty_generics, where_clause) = input.generics.split_for_impl();
let where_clause = WhereClause {
clause: where_clause.clone(),
inner: where_clause.clone(),
params: &input.generics.ty_params,
trait_path,
bounded_types: HashSet::new()