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#![allow(dead_code)]
#![allow(unused_variables)]
#![allow(unreachable_code)]
#![allow(unused_imports)]
use std::borrow::Cow;
use std::cmp::max;
use std::collections::HashMap;
use crate::error::{TypeError, TypeMessage};
use crate::semantics::core::context::TyCtx;
use crate::semantics::nze::{NameEnv, QuoteEnv};
use crate::semantics::phase::normalize::{merge_maps, NzEnv};
use crate::semantics::phase::typecheck::{
builtin_to_value, const_to_value, type_of_builtin,
};
use crate::semantics::phase::Normalized;
use crate::semantics::{
AlphaVar, Binder, Closure, TyExpr, TyExprKind, Type, Value, ValueKind,
};
use crate::syntax;
use crate::syntax::{
Builtin, Const, Expr, ExprKind, InterpolatedTextContents, Label, Span,
UnspannedExpr, V,
};
#[derive(Debug, Clone)]
pub(crate) struct TyEnv {
names: NameEnv,
items: NzEnv,
}
impl TyEnv {
pub fn new() -> Self {
TyEnv {
names: NameEnv::new(),
items: NzEnv::new(),
}
}
pub fn as_quoteenv(&self) -> QuoteEnv {
self.names.as_quoteenv()
}
pub fn as_nzenv(&self) -> &NzEnv {
&self.items
}
pub fn as_nameenv(&self) -> &NameEnv {
&self.names
}
pub fn insert_type(&self, x: &Label, t: Value) -> Self {
TyEnv {
names: self.names.insert(x),
items: self.items.insert_type(t),
}
}
pub fn insert_value(&self, x: &Label, e: Value) -> Self {
TyEnv {
names: self.names.insert(x),
items: self.items.insert_value(e),
}
}
pub fn lookup(&self, var: &V<Label>) -> Option<(TyExprKind, Value)> {
let var = self.names.unlabel_var(var)?;
let ty = self.items.lookup_val(&var).get_type().unwrap();
Some((TyExprKind::Var(var), ty))
}
pub fn size(&self) -> usize {
self.names.size()
}
}
fn mkerr<T>(x: impl ToString) -> Result<T, TypeError> {
Err(TypeError::new(TypeMessage::Custom(x.to_string())))
}
fn type_last_layer(
env: &TyEnv,
kind: &ExprKind<TyExpr, Normalized>,
) -> Result<Value, TypeError> {
Ok(match &kind {
ExprKind::Import(..) => unreachable!(
"There should remain no imports in a resolved expression"
),
ExprKind::Var(..)
| ExprKind::Lam(..)
| ExprKind::Pi(..)
| ExprKind::Let(..)
| ExprKind::Const(Const::Sort)
| ExprKind::Embed(..) => unreachable!(),
ExprKind::Const(Const::Type) => const_to_value(Const::Kind),
ExprKind::Const(Const::Kind) => const_to_value(Const::Sort),
ExprKind::Builtin(b) => {
type_with(env, &type_of_builtin(*b))?.normalize_whnf(env.as_nzenv())
}
ExprKind::BoolLit(_) => builtin_to_value(Builtin::Bool),
ExprKind::NaturalLit(_) => builtin_to_value(Builtin::Natural),
ExprKind::IntegerLit(_) => builtin_to_value(Builtin::Integer),
ExprKind::DoubleLit(_) => builtin_to_value(Builtin::Double),
ExprKind::Annot(x, t) => {
if x.get_type()? != t.normalize_whnf(env.as_nzenv()) {
return mkerr("annot mismatch");
}
x.normalize_whnf(env.as_nzenv())
}
ExprKind::App(f, arg) => {
let tf = f.get_type()?;
let tf_borrow = tf.as_whnf();
let (expected_arg_ty, ty_closure) = match &*tf_borrow {
ValueKind::PiClosure { annot, closure, .. } => (annot, closure),
_ => return mkerr(format!("apply to not Pi: {:?}", tf_borrow)),
};
// if arg.get_type()? != *expected_arg_ty {
// return mkerr(format!(
// "function annot mismatch: {:?}, {:?}",
// arg.get_type()?,
// expected_arg_ty
// ));
// }
let arg_nf = arg.normalize_whnf(env.as_nzenv());
ty_closure.apply(arg_nf)
}
ExprKind::BoolIf(x, y, z) => {
if *x.get_type()?.as_whnf()
!= ValueKind::from_builtin(Builtin::Bool)
{
return mkerr("InvalidPredicate");
}
if y.get_type()?.get_type()?.as_const() != Some(Const::Type) {
return mkerr("IfBranchMustBeTerm");
}
if z.get_type()?.get_type()?.as_const() != Some(Const::Type) {
return mkerr("IfBranchMustBeTerm");
}
if y.get_type()? != z.get_type()? {
return mkerr("IfBranchMismatch");
}
y.get_type()?
}
_ => Value::from_const(Const::Type), // TODO
})
}
/// Type-check an expression and return the expression alongside its type if type-checking
/// succeeded, or an error if type-checking failed.
fn type_with(
env: &TyEnv,
expr: &Expr<Normalized>,
) -> Result<TyExpr, TypeError> {
let (tyekind, ty) = match expr.as_ref() {
ExprKind::Var(var) => match env.lookup(&var) {
Some((k, ty)) => (k, Some(ty)),
None => return mkerr("unbound variable"),
},
ExprKind::Lam(binder, annot, body) => {
let annot = type_with(env, annot)?;
let annot_nf = annot.normalize_whnf(env.as_nzenv());
let body =
type_with(&env.insert_type(&binder, annot_nf.clone()), body)?;
let ty = Value::from_kind_and_type(
ValueKind::PiClosure {
binder: Binder::new(binder.clone()),
annot: annot_nf,
closure: Closure::new(
env.as_nzenv(),
body.get_type()?.to_tyexpr(env.as_quoteenv().insert()),
),
},
Value::from_const(Const::Type), // TODO: function_check
);
(
TyExprKind::Expr(ExprKind::Lam(binder.clone(), annot, body)),
Some(ty),
)
}
ExprKind::Pi(binder, annot, body) => {
let annot = type_with(env, annot)?;
let annot_nf = annot.normalize_whnf(env.as_nzenv());
let body =
type_with(&env.insert_type(binder, annot_nf.clone()), body)?;
(
TyExprKind::Expr(ExprKind::Pi(binder.clone(), annot, body)),
Some(Value::from_const(Const::Type)), // TODO: function_check
)
}
ExprKind::Let(binder, annot, val, body) => {
let v = if let Some(t) = annot {
t.rewrap(ExprKind::Annot(val.clone(), t.clone()))
} else {
val.clone()
};
let val = type_with(env, val)?;
let val_nf = val.normalize_whnf(&env.as_nzenv());
let body = type_with(&env.insert_value(&binder, val_nf), body)?;
let body_ty = body.get_type().ok();
(
TyExprKind::Expr(ExprKind::Let(
binder.clone(),
None,
val,
body,
)),
body_ty,
)
}
ExprKind::Const(Const::Sort) => {
(TyExprKind::Expr(ExprKind::Const(Const::Sort)), None)
}
ExprKind::Embed(p) => {
return Ok(p.clone().into_typed().into_value().to_tyexpr_noenv())
}
ekind => {
let ekind = ekind.traverse_ref(|e| type_with(env, e))?;
let ty = type_last_layer(env, &ekind)?;
(TyExprKind::Expr(ekind), Some(ty))
}
};
Ok(TyExpr::new(tyekind, ty, expr.span()))
}
pub(crate) fn typecheck(e: &Expr<Normalized>) -> Result<TyExpr, TypeError> {
type_with(&TyEnv::new(), e)
}
|
