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//! Items which do not have a correspondence to any API in the proc_macro crate,
//! but are necessary to include in proc-macro2.
use crate::fallback;
use crate::imp;
use crate::marker::Marker;
use crate::Span;
use core::fmt::{self, Debug};
/// An object that holds a [`Group`]'s `span_open()` and `span_close()` together
/// (in a more compact representation than holding those 2 spans individually.
///
/// [`Group`]: crate::Group
#[derive(Copy, Clone)]
pub struct DelimSpan {
inner: DelimSpanEnum,
_marker: Marker,
}
#[derive(Copy, Clone)]
enum DelimSpanEnum {
#[cfg(wrap_proc_macro)]
Compiler {
join: proc_macro::Span,
open: proc_macro::Span,
close: proc_macro::Span,
},
Fallback(fallback::Span),
}
impl DelimSpan {
pub(crate) fn new(group: &imp::Group) -> Self {
#[cfg(wrap_proc_macro)]
let inner = match group {
imp::Group::Compiler(group) => DelimSpanEnum::Compiler {
join: group.span(),
open: group.span_open(),
close: group.span_close(),
},
imp::Group::Fallback(group) => DelimSpanEnum::Fallback(group.span()),
};
#[cfg(not(wrap_proc_macro))]
let inner = DelimSpanEnum::Fallback(group.span());
DelimSpan {
inner,
_marker: Marker,
}
}
/// Returns a span covering the entire delimited group.
pub fn join(&self) -> Span {
match &self.inner {
#[cfg(wrap_proc_macro)]
DelimSpanEnum::Compiler { join, .. } => Span::_new(imp::Span::Compiler(*join)),
DelimSpanEnum::Fallback(span) => Span::_new_fallback(*span),
}
}
/// Returns a span for the opening punctuation of the group only.
pub fn open(&self) -> Span {
match &self.inner {
#[cfg(wrap_proc_macro)]
DelimSpanEnum::Compiler { open, .. } => Span::_new(imp::Span::Compiler(*open)),
DelimSpanEnum::Fallback(span) => Span::_new_fallback(span.first_byte()),
}
}
/// Returns a span for the closing punctuation of the group only.
pub fn close(&self) -> Span {
match &self.inner {
#[cfg(wrap_proc_macro)]
DelimSpanEnum::Compiler { close, .. } => Span::_new(imp::Span::Compiler(*close)),
DelimSpanEnum::Fallback(span) => Span::_new_fallback(span.last_byte()),
}
}
}
impl Debug for DelimSpan {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
Debug::fmt(&self.join(), f)
}
}