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// Copyright 2018 Syn Developers
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#[cfg(feature = "fold")]
pub mod fold {
use fold::Fold;
use proc_macro2::Span;
use punctuated::{Pair, Punctuated};
pub trait FoldHelper {
type Item;
fn lift<F>(self, f: F) -> Self
where
F: FnMut(Self::Item) -> Self::Item;
}
impl<T> FoldHelper for Vec<T> {
type Item = T;
fn lift<F>(self, f: F) -> Self
where
F: FnMut(Self::Item) -> Self::Item,
{
self.into_iter().map(f).collect()
}
}
impl<T, U> FoldHelper for Punctuated<T, U> {
type Item = T;
fn lift<F>(self, mut f: F) -> Self
where
F: FnMut(Self::Item) -> Self::Item,
{
self.into_pairs()
.map(Pair::into_tuple)
.map(|(t, u)| Pair::new(f(t), u))
.collect()
}
}
pub fn tokens_helper<F: Fold + ?Sized, S: Spans>(folder: &mut F, spans: &S) -> S {
spans.fold(folder)
}
pub trait Spans {
fn fold<F: Fold + ?Sized>(&self, folder: &mut F) -> Self;
}
impl Spans for Span {
fn fold<F: Fold + ?Sized>(&self, folder: &mut F) -> Self {
folder.fold_span(*self)
}
}
impl Spans for [Span; 1] {
fn fold<F: Fold + ?Sized>(&self, folder: &mut F) -> Self {
[folder.fold_span(self[0])]
}
}
impl Spans for [Span; 2] {
fn fold<F: Fold + ?Sized>(&self, folder: &mut F) -> Self {
[folder.fold_span(self[0]), folder.fold_span(self[1])]
}
}
impl Spans for [Span; 3] {
fn fold<F: Fold + ?Sized>(&self, folder: &mut F) -> Self {
[
folder.fold_span(self[0]),
folder.fold_span(self[1]),
folder.fold_span(self[2]),
]
}
}
}
#[cfg(feature = "visit")]
pub mod visit {
use proc_macro2::Span;
use visit::Visit;
pub fn tokens_helper<'ast, V: Visit<'ast> + ?Sized, S: Spans>(visitor: &mut V, spans: &'ast S) {
spans.visit(visitor);
}
pub trait Spans {
fn visit<'ast, V: Visit<'ast> + ?Sized>(&'ast self, visitor: &mut V);
}
impl Spans for Span {
fn visit<'ast, V: Visit<'ast> + ?Sized>(&'ast self, visitor: &mut V) {
visitor.visit_span(self);
}
}
impl Spans for [Span; 1] {
fn visit<'ast, V: Visit<'ast> + ?Sized>(&'ast self, visitor: &mut V) {
visitor.visit_span(&self[0]);
}
}
impl Spans for [Span; 2] {
fn visit<'ast, V: Visit<'ast> + ?Sized>(&'ast self, visitor: &mut V) {
visitor.visit_span(&self[0]);
visitor.visit_span(&self[1]);
}
}
impl Spans for [Span; 3] {
fn visit<'ast, V: Visit<'ast> + ?Sized>(&'ast self, visitor: &mut V) {
visitor.visit_span(&self[0]);
visitor.visit_span(&self[1]);
visitor.visit_span(&self[2]);
}
}
}
#[cfg(feature = "visit-mut")]
pub mod visit_mut {
use proc_macro2::Span;
use visit_mut::VisitMut;
pub fn tokens_helper<V: VisitMut + ?Sized, S: Spans>(visitor: &mut V, spans: &mut S) {
spans.visit_mut(visitor);
}
pub trait Spans {
fn visit_mut<V: VisitMut + ?Sized>(&mut self, visitor: &mut V);
}
impl Spans for Span {
fn visit_mut<V: VisitMut + ?Sized>(&mut self, visitor: &mut V) {
visitor.visit_span_mut(self);
}
}
impl Spans for [Span; 1] {
fn visit_mut<V: VisitMut + ?Sized>(&mut self, visitor: &mut V) {
visitor.visit_span_mut(&mut self[0]);
}
}
impl Spans for [Span; 2] {
fn visit_mut<V: VisitMut + ?Sized>(&mut self, visitor: &mut V) {
visitor.visit_span_mut(&mut self[0]);
visitor.visit_span_mut(&mut self[1]);
}
}
impl Spans for [Span; 3] {
fn visit_mut<V: VisitMut + ?Sized>(&mut self, visitor: &mut V) {
visitor.visit_span_mut(&mut self[0]);
visitor.visit_span_mut(&mut self[1]);
visitor.visit_span_mut(&mut self[2]);
}
}
}