1use proc_macro2::{Ident, Span, TokenStream};
2use quote::ToTokens;
3use syn::LitStr;
4
5use std::ops::{Deref, DerefMut};
6
7/// An entity with a span attached.
8#[derive(Debug, Copy, Clone)]
9pub(crate) struct Sp<T> {
10 val: T,
11 span: Span,
12}
13
14impl<T> Sp<T> {
15 pub(crate) fn new(val: T, span: Span) -> Self {
16 Sp { val, span }
17 }
18
19 pub(crate) fn get(&self) -> &T {
20 &self.val
21 }
22
23 pub(crate) fn span(&self) -> Span {
24 self.span
25 }
26}
27
28impl<T> Deref for Sp<T> {
29 type Target = T;
30
31 fn deref(&self) -> &T {
32 &self.val
33 }
34}
35
36impl<T> DerefMut for Sp<T> {
37 fn deref_mut(&mut self) -> &mut T {
38 &mut self.val
39 }
40}
41
42impl From<Ident> for Sp<String> {
43 fn from(ident: Ident) -> Self {
44 Sp {
45 val: ident.to_string(),
46 span: ident.span(),
47 }
48 }
49}
50
51impl From<LitStr> for Sp<String> {
52 fn from(lit: LitStr) -> Self {
53 Sp {
54 val: lit.value(),
55 span: lit.span(),
56 }
57 }
58}
59
60impl<'a> From<Sp<&'a str>> for Sp<String> {
61 fn from(sp: Sp<&'a str>) -> Self {
62 Sp::new(sp.val.into(), sp.span)
63 }
64}
65
66impl<U, T: PartialEq<U>> PartialEq<U> for Sp<T> {
67 fn eq(&self, other: &U) -> bool {
68 self.val == *other
69 }
70}
71
72impl<T: AsRef<str>> AsRef<str> for Sp<T> {
73 fn as_ref(&self) -> &str {
74 self.val.as_ref()
75 }
76}
77
78impl<T: ToTokens> ToTokens for Sp<T> {
79 fn to_tokens(&self, stream: &mut TokenStream) {
80 // this is the simplest way out of correct ones to change span on
81 // arbitrary token tree I could come up with
82 let tt: impl Iterator = self.val.to_token_stream().into_iter().map(|mut tt: TokenTree| {
83 tt.set_span(self.span);
84 tt
85 });
86
87 stream.extend(iter:tt);
88 }
89}
90