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//! This module implements the runtime representation of functions.
use std::{
cell::{Ref, RefCell, RefMut},
collections::HashMap,
rc::Rc,
};
use crate::{
chunk::Chunk,
upvalues::{UpvalueCarrier, Upvalues},
};
use super::NixString;
#[derive(Clone, Debug, PartialEq)]
pub(crate) struct Formals {
/// Map from argument name, to whether that argument is required
pub(crate) arguments: HashMap<NixString, bool>,
/// Do the formals of this function accept extra arguments
pub(crate) ellipsis: bool,
}
/// The opcodes for a thunk or closure, plus the number of
/// non-executable opcodes which are allowed after an OpClosure or
/// OpThunk referencing it. At runtime `Lambda` is usually wrapped
/// in `Rc` to avoid copying the `Chunk` it holds (which can be
/// quite large).
#[derive(Debug, PartialEq)]
pub struct Lambda {
pub(crate) chunk: Chunk,
/// Number of upvalues which the code in this Lambda closes
/// over, and which need to be initialised at
/// runtime. Information about the variables is emitted using
/// data-carrying opcodes (see [`OpCode::DataLocalIdx`]).
pub(crate) upvalue_count: usize,
pub(crate) formals: Option<Formals>,
}
impl Lambda {
pub fn new_anonymous() -> Self {
Lambda {
chunk: Default::default(),
upvalue_count: 0,
formals: None,
}
}
pub fn chunk(&mut self) -> &mut Chunk {
&mut self.chunk
}
}
#[derive(Clone, Debug, PartialEq)]
pub struct InnerClosure {
pub lambda: Rc<Lambda>,
upvalues: Upvalues,
}
#[repr(transparent)]
#[derive(Clone, Debug, PartialEq)]
pub struct Closure(Rc<RefCell<InnerClosure>>);
impl Closure {
pub fn new(lambda: Rc<Lambda>) -> Self {
Closure(Rc::new(RefCell::new(InnerClosure {
upvalues: Upvalues::with_capacity(lambda.upvalue_count),
lambda,
})))
}
pub fn chunk(&self) -> Ref<'_, Chunk> {
Ref::map(self.0.borrow(), |c| &c.lambda.chunk)
}
pub fn lambda(&self) -> Rc<Lambda> {
self.0.borrow().lambda.clone()
}
}
impl UpvalueCarrier for Closure {
fn upvalue_count(&self) -> usize {
self.0.borrow().lambda.upvalue_count
}
fn upvalues(&self) -> Ref<'_, Upvalues> {
Ref::map(self.0.borrow(), |c| &c.upvalues)
}
fn upvalues_mut(&self) -> RefMut<'_, Upvalues> {
RefMut::map(self.0.borrow_mut(), |c| &mut c.upvalues)
}
}
|
