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|
use std::cell::RefCell;
use std::collections::{HashMap, HashSet};
use std::convert::TryInto;
use std::mem;
use void::{ResultVoidExt, Void};
use crate::ast::hir::{Decl, Expr};
use crate::ast::{self, Ident};
use super::Visitor;
#[derive(Default)]
pub(crate) struct Monomorphize<'a, 'ast> {
decls: HashMap<&'a Ident<'ast>, &'a Decl<'ast, ast::Type<'ast>>>,
extra_decls: Vec<Decl<'ast, ast::Type<'ast>>>,
remove_decls: HashSet<Ident<'ast>>,
}
impl<'a, 'ast> Monomorphize<'a, 'ast> {
pub(crate) fn new() -> Self {
Default::default()
}
}
impl<'a, 'ast> Visitor<'a, 'ast, ast::Type<'ast>> for Monomorphize<'a, 'ast> {
type Error = Void;
fn post_visit_call(
&mut self,
fun: &mut Expr<'ast, ast::Type<'ast>>,
type_args: &mut HashMap<Ident<'ast>, ast::Type<'ast>>,
args: &mut Vec<Expr<'ast, ast::Type<'ast>>>,
) -> Result<(), Self::Error> {
let new_fun = match fun {
Expr::Ident(id, _) => {
let decl: Decl<_> = (**self.decls.get(id).unwrap()).clone();
let name = RefCell::new(id.to_string());
let type_args = mem::take(type_args);
let mut monomorphized = decl
.traverse_type(|ty| -> Result<_, Void> {
Ok(ty.clone().traverse_type_vars(|v| {
let concrete = type_args.get(&v).unwrap();
name.borrow_mut().push_str(&concrete.to_string());
concrete.clone()
}))
})
.void_unwrap();
let name: Ident = name.into_inner().try_into().unwrap();
if name != *id {
self.remove_decls.insert(id.clone());
monomorphized.set_name(name.clone());
let type_ = monomorphized.type_().unwrap().clone();
self.extra_decls.push(monomorphized);
Some(Expr::Ident(name, type_))
} else {
None
}
}
_ => todo!(),
};
if let Some(new_fun) = new_fun {
*fun = new_fun;
}
Ok(())
}
fn post_visit_decl(
&mut self,
decl: &'a Decl<'ast, ast::Type<'ast>>,
) -> Result<(), Self::Error> {
self.decls.insert(decl.name(), decl);
Ok(())
}
}
pub(crate) fn run_toplevel<'a>(toplevel: &mut Vec<Decl<'a, ast::Type<'a>>>) {
let mut pass = Monomorphize::new();
for decl in toplevel.iter_mut() {
pass.visit_decl(decl).void_unwrap();
}
let remove_decls = mem::take(&mut pass.remove_decls);
let mut extra_decls = mem::take(&mut pass.extra_decls);
toplevel.retain(|decl| !remove_decls.contains(decl.name()));
extra_decls.append(toplevel);
*toplevel = extra_decls;
}
#[cfg(test)]
mod tests {
use std::convert::TryFrom;
use super::*;
use crate::parser::toplevel;
use crate::tc::typecheck_toplevel;
#[test]
fn call_id_decl() {
let (_, program) = toplevel(
"ty id : fn a -> a
fn id x = x
ty main : fn -> int
fn main = id 0",
)
.unwrap();
let mut program = typecheck_toplevel(program).unwrap();
run_toplevel(&mut program);
let find_decl = |ident: &str| {
program.iter().find(|decl| {
matches!(decl, Decl::Fun {name, ..} if name == &Ident::try_from(ident).unwrap())
}).unwrap()
};
let main = find_decl("main");
let body = match main {
Decl::Fun { body, .. } => body,
_ => unreachable!(),
};
let expected_type = ast::Type::Function(ast::FunctionType {
args: vec![ast::Type::Int],
ret: Box::new(ast::Type::Int),
});
match &**body {
Expr::Call { fun, .. } => {
let fun = match &**fun {
Expr::Ident(fun, _) => fun,
_ => unreachable!(),
};
let called_decl = find_decl(fun.into());
assert_eq!(called_decl.type_().unwrap(), &expected_type);
}
_ => unreachable!(),
}
}
}
|
