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use ahash::AHashMap;
use crate::interpreter::Capture;
use super::*;
/// Scan and declare all (nested or not) captured variable before compile closure
pub struct CaptureScanner<'a, Buffer: IoWrite> {
pub register_table: &'a mut RegisterTable,
pub gc: &'a mut Gc<Buffer>,
pub insts: &'a mut Vec<VmInst>,
pub overridden: AHashMap<String, usize>,
}
impl<'a, Buffer: IoWrite> CaptureScanner<'a, Buffer> {
pub fn scan_expr(&mut self, expr: &Expr) {
match expr {
Expr::Block { body, .. } => body.iter().for_each(|stmt| self.scan_stmt(stmt)),
Expr::If {
conditional,
default,
..
} => conditional.iter().for_each(|(expr, stmts)| {
self.scan_expr(expr);
stmts.iter().for_each(|stmt| self.scan_stmt(stmt));
if let Some(stmts) = default {
stmts.iter().for_each(|stmt| self.scan_stmt(stmt))
}
}),
Expr::Prefix { rhs, .. } => self.scan_expr(rhs),
Expr::Call {
lhs, parameters, ..
} => {
self.scan_expr(lhs);
parameters.iter().for_each(|expr| self.scan_expr(expr));
}
Expr::Index { lhs, rhs, .. } => {
self.scan_expr(lhs);
self.scan_expr(rhs);
}
Expr::OpenRange { lhs, .. } => {
self.scan_expr(&Expr::Id {
loc: Loc {
start: 0,
end: 0,
fid: usize::MAX,
},
name: "Range".to_string(),
});
self.scan_expr(lhs);
}
// Member rhs can not have legal constant values
Expr::Infix {
lhs,
op: OpInfix::Member | OpInfix::DoubleColon,
..
} => {
self.scan_expr(lhs);
}
Expr::Infix { lhs, rhs, op, .. } => {
// x..y implicitly use `Range`
if matches!(op, OpInfix::Range) {
self.scan_expr(&Expr::Id {
loc: Loc {
start: 0,
end: 0,
fid: usize::MAX,
},
name: "Range".to_string(),
});
}
self.scan_expr(lhs);
self.scan_expr(rhs);
}
Expr::Fn {
parameters, body, ..
} => {
// Parameters will override upper scope variables
parameters.iter().for_each(|(name, _)| {
if let Some(count) = self.overridden.get_mut(name) {
*count += 1
} else {
self.overridden.insert(name.clone(), 1);
}
});
self.scan_expr(body);
parameters.iter().for_each(|(name, _)| {
let count = self.overridden.get_mut(name).unwrap();
*count -= 1;
if *count == 0 {
self.overridden.remove(name);
}
})
}
Expr::Id { name, .. } => {
if self.overridden.get(name).is_some() {
return;
}
if let Some((id, depth, loc)) = self.register_table.lookup_variable(name) {
// variable is captured
// make a local copy and register capture info
if depth > 0 {
assert_eq!(depth, 1);
let local_id = self.register_table.declare_captured_variable(name, loc);
self.register_table.capture.push(Capture {
rd: local_id,
rs: id,
});
}
}
}
Expr::Parentheses { content, .. } => self.scan_expr(content),
Expr::Const { value, .. } => self.scan_const(value),
Expr::_Module { .. } => todo!(),
Expr::Error => unreachable!(),
}
}
pub fn scan_stmt(&mut self, stmt: &Stmt) {
match stmt {
Stmt::Expr { expr, .. } => self.scan_expr(expr),
Stmt::Continue { .. } => (),
Stmt::Break { .. } => (),
Stmt::Return { value, .. } => {
if let Some(expr) = value {
self.scan_expr(expr)
}
}
Stmt::Loop {
condition, body, ..
} => {
if let Some(expr) = condition {
self.scan_expr(expr)
}
body.iter().for_each(|stmt| self.scan_stmt(stmt));
}
Stmt::For { iterator, body, .. } => {
// For macro implicitly use `Option`
self.scan_expr(&Expr::Id {
loc: Loc {
start: 0,
end: 0,
fid: usize::MAX,
},
name: "Option".to_string(),
});
self.scan_expr(iterator);
body.iter().for_each(|stmt| self.scan_stmt(stmt));
}
Stmt::Def {
variable,
parameters,
body,
..
} => {
self.scan_expr(variable);
// Parameters will override upper scope variables
parameters.iter().for_each(|(name, _)| {
if let Some(count) = self.overridden.get_mut(name) {
*count += 1
} else {
self.overridden.insert(name.clone(), 1);
}
});
body.iter().for_each(|stmt| self.scan_stmt(stmt));
parameters.iter().for_each(|(name, _)| {
let count = self.overridden.get_mut(name).unwrap();
*count -= 1;
if *count == 0 {
self.overridden.remove(name);
}
})
}
Stmt::Error => unreachable!(),
}
}
fn scan_const(&mut self, constant: &Const) {
match constant {
Const::List(list) => {
list.iter().for_each(|expr| self.scan_expr(expr));
}
Const::Table(entries) => {
entries.iter().for_each(|(_, expr, _)| self.scan_expr(expr));
}
_ => (),
}
}
}