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use crate::arena::Arena;
/// Helper class to emit expressions
#[allow(dead_code)]
#[derive(Default, Debug)]
pub struct Emitter {
start_len: Option<usize>,
}
#[allow(dead_code)]
impl Emitter {
pub fn start(&mut self, arena: &Arena<crate::Expression>) {
if self.start_len.is_some() {
unreachable!("Emitting has already started!");
}
self.start_len = Some(arena.len());
}
pub const fn is_running(&self) -> bool {
self.start_len.is_some()
}
#[must_use]
pub fn finish(
&mut self,
arena: &Arena<crate::Expression>,
) -> Option<(crate::Statement, crate::span::Span)> {
let start_len = self.start_len.take().unwrap();
if start_len != arena.len() {
#[allow(unused_mut)]
let mut span = crate::span::Span::default();
let range = arena.range_from(start_len);
for handle in range.clone() {
span.subsume(arena.get_span(handle))
}
Some((crate::Statement::Emit(range), span))
} else {
None
}
}
}
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