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use proc_macro2::{Ident, Span, TokenStream};
use quote::ToTokens;
use syn::LitStr;
use std::ops::{Deref, DerefMut};
/// An entity with a span attached.
#[derive(Debug, Copy, Clone)]
pub struct Sp<T> {
val: T,
span: Span,
}
impl<T> Sp<T> {
pub fn new(val: T, span: Span) -> Self {
Sp { val, span }
}
pub fn get(&self) -> &T {
&self.val
}
pub fn span(&self) -> Span {
self.span
}
}
impl<T> Deref for Sp<T> {
type Target = T;
fn deref(&self) -> &T {
&self.val
}
}
impl<T> DerefMut for Sp<T> {
fn deref_mut(&mut self) -> &mut T {
&mut self.val
}
}
impl From<Ident> for Sp<String> {
fn from(ident: Ident) -> Self {
Sp {
val: ident.to_string(),
span: ident.span(),
}
}
}
impl From<LitStr> for Sp<String> {
fn from(lit: LitStr) -> Self {
Sp {
val: lit.value(),
span: lit.span(),
}
}
}
impl<'a> From<Sp<&'a str>> for Sp<String> {
fn from(sp: Sp<&'a str>) -> Self {
Sp::new(sp.val.into(), sp.span)
}
}
impl<U, T: PartialEq<U>> PartialEq<U> for Sp<T> {
fn eq(&self, other: &U) -> bool {
self.val == *other
}
}
impl<T: AsRef<str>> AsRef<str> for Sp<T> {
fn as_ref(&self) -> &str {
self.val.as_ref()
}
}
impl<T: ToTokens> ToTokens for Sp<T> {
fn to_tokens(&self, stream: &mut TokenStream) {
// this is the simplest way out of correct ones to change span on
// arbitrary token tree I could come up with
let tt = self.val.to_token_stream().into_iter().map(|mut tt| {
tt.set_span(self.span);
tt
});
stream.extend(tt);
}
}