1//! Items which do not have a correspondence to any API in the proc_macro crate,
2//! but are necessary to include in proc-macro2.
3
4use crate::fallback;
5use crate::imp;
6use crate::marker::Marker;
7use crate::Span;
8use core::fmt::{self, Debug};
9
10/// An object that holds a [`Group`]'s `span_open()` and `span_close()` together
11/// (in a more compact representation than holding those 2 spans individually.
12///
13/// [`Group`]: crate::Group
14#[derive(Copy, Clone)]
15pub struct DelimSpan {
16 inner: DelimSpanEnum,
17 _marker: Marker,
18}
19
20#[derive(Copy, Clone)]
21enum DelimSpanEnum {
22 #[cfg(wrap_proc_macro)]
23 Compiler {
24 join: proc_macro::Span,
25 #[cfg(not(no_group_open_close))]
26 open: proc_macro::Span,
27 #[cfg(not(no_group_open_close))]
28 close: proc_macro::Span,
29 },
30 Fallback(fallback::Span),
31}
32
33impl DelimSpan {
34 pub(crate) fn new(group: &imp::Group) -> Self {
35 #[cfg(wrap_proc_macro)]
36 let inner = match group {
37 imp::Group::Compiler(group) => DelimSpanEnum::Compiler {
38 join: group.span(),
39 #[cfg(not(no_group_open_close))]
40 open: group.span_open(),
41 #[cfg(not(no_group_open_close))]
42 close: group.span_close(),
43 },
44 imp::Group::Fallback(group) => DelimSpanEnum::Fallback(group.span()),
45 };
46
47 #[cfg(not(wrap_proc_macro))]
48 let inner = DelimSpanEnum::Fallback(group.span());
49
50 DelimSpan {
51 inner,
52 _marker: Marker,
53 }
54 }
55
56 /// Returns a span covering the entire delimited group.
57 pub fn join(&self) -> Span {
58 match &self.inner {
59 #[cfg(wrap_proc_macro)]
60 DelimSpanEnum::Compiler { join, .. } => Span::_new(imp::Span::Compiler(*join)),
61 DelimSpanEnum::Fallback(span) => Span::_new_fallback(*span),
62 }
63 }
64
65 /// Returns a span for the opening punctuation of the group only.
66 pub fn open(&self) -> Span {
67 match &self.inner {
68 #[cfg(wrap_proc_macro)]
69 DelimSpanEnum::Compiler {
70 #[cfg(not(no_group_open_close))]
71 open,
72 #[cfg(no_group_open_close)]
73 join: open,
74 ..
75 } => Span::_new(imp::Span::Compiler(*open)),
76 DelimSpanEnum::Fallback(span) => Span::_new_fallback(span.first_byte()),
77 }
78 }
79
80 /// Returns a span for the closing punctuation of the group only.
81 pub fn close(&self) -> Span {
82 match &self.inner {
83 #[cfg(wrap_proc_macro)]
84 DelimSpanEnum::Compiler {
85 #[cfg(not(no_group_open_close))]
86 close,
87 #[cfg(no_group_open_close)]
88 join: close,
89 ..
90 } => Span::_new(imp::Span::Compiler(*close)),
91 DelimSpanEnum::Fallback(span) => Span::_new_fallback(span.last_byte()),
92 }
93 }
94}
95
96impl Debug for DelimSpan {
97 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
98 Debug::fmt(&self.join(), f)
99 }
100}
101