rune/compile/v1/
breaks.rs

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1use crate as rune;
2use crate::alloc::prelude::*;
3use crate::alloc::{self, Vec};
4use crate::ast::Spanned;
5use crate::compile::{self, ErrorKind, WithSpan};
6use crate::runtime::{InstAddress, Label, Output};
7
8/// Loops we are inside.
9#[derive(TryClone)]
10pub(crate) struct Break<'hir> {
11    /// The optional label of the start of the break.
12    pub(crate) label: Option<&'hir str>,
13    /// If the break supports breaking with a value, this would be where to
14    /// store it.
15    pub(crate) output: Option<Output>,
16    /// If the break supports continuing, this is the label to use.
17    pub(crate) continue_label: Option<Label>,
18    /// The end label of the break, used for `break`.
19    pub(crate) break_label: Label,
20    /// Locals to drop when breaking.
21    pub(crate) drop: Option<InstAddress>,
22}
23
24pub(crate) struct Breaks<'hir> {
25    loops: Vec<Break<'hir>>,
26}
27
28impl<'hir> Breaks<'hir> {
29    /// Construct a new collection of loops.
30    pub(crate) fn new() -> Self {
31        Self { loops: Vec::new() }
32    }
33
34    /// Get the last loop context.
35    pub(crate) fn last(&self) -> Option<&Break<'hir>> {
36        self.loops.last()
37    }
38
39    /// Push loop information.
40    pub(crate) fn push(&mut self, l: Break<'hir>) -> alloc::Result<()> {
41        self.loops.try_push(l)?;
42        Ok(())
43    }
44
45    pub(crate) fn pop(&mut self) {
46        let empty = self.loops.pop().is_some();
47        debug_assert!(empty);
48    }
49
50    /// Find the loop with the matching label and collect addresses to drop.
51    pub(crate) fn walk_until_label(
52        &self,
53        span: &dyn Spanned,
54        expected: &str,
55        drop: &mut Vec<InstAddress>,
56    ) -> compile::Result<&Break<'hir>> {
57        drop.clear();
58        self.find_label_inner(span, expected, &mut |l| drop.try_extend(l.drop))
59    }
60
61    /// Find the loop with the matching label.
62    pub(crate) fn find_label(
63        &self,
64        span: &dyn Spanned,
65        expected: &str,
66    ) -> compile::Result<&Break<'hir>> {
67        self.find_label_inner(span, expected, &mut |_| Ok(()))
68    }
69
70    /// Find the loop with the matching label.
71    fn find_label_inner(
72        &self,
73        span: &dyn Spanned,
74        expected: &str,
75        visitor: &mut dyn FnMut(&Break<'hir>) -> alloc::Result<()>,
76    ) -> compile::Result<&Break<'hir>> {
77        for l in self.loops.iter().rev() {
78            visitor(l).with_span(span)?;
79
80            let Some(label) = l.label else {
81                continue;
82            };
83
84            if expected == label {
85                return Ok(l);
86            }
87        }
88
89        Err(compile::Error::new(
90            span,
91            ErrorKind::MissingLabel {
92                label: expected.try_into()?,
93            },
94        ))
95    }
96}
rune/compile/v1/breaks.rs

rune/compile/v1/
breaks.rs
