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-rw-r--r--dhall/src/typecheck.rs117
1 files changed, 92 insertions, 25 deletions
diff --git a/dhall/src/typecheck.rs b/dhall/src/typecheck.rs
index a53e88a..19d7eee 100644
--- a/dhall/src/typecheck.rs
+++ b/dhall/src/typecheck.rs
@@ -32,6 +32,9 @@ impl<'a> Resolved<'a> {
}
}
impl<'a> Typed<'a> {
+ fn normalize_to_type(self) -> Type<'a> {
+ self.normalize().into_type()
+ }
fn get_type_move(self) -> Result<Type<'static>, TypeError> {
let (expr, ty) = (self.0, self.1);
ty.ok_or_else(|| {
@@ -57,6 +60,16 @@ impl<'a> Normalized<'a> {
_ => TypeInternal::Expr(Box::new(self)),
})
}
+ fn get_type_move(self) -> Result<Type<'static>, TypeError> {
+ let (expr, ty) = (self.0, self.1);
+ ty.ok_or_else(|| {
+ TypeError::new(
+ &TypecheckContext::new(),
+ expr.embed_absurd(),
+ TypeMessage::Untyped,
+ )
+ })
+ }
}
impl Normalized<'static> {
fn embed<N>(self) -> SubExpr<N, Normalized<'static>> {
@@ -141,6 +154,30 @@ impl<'a> TypeInternal<'a> {
}
#[derive(Debug, Clone)]
+pub(crate) enum TypedImproved {
+ // Pi(TypecheckContext, Const, Label, Type<'static>, Type<'static>),
+ Expr(Typed<'static>),
+}
+
+impl TypedImproved {
+ fn into_typed(self) -> Result<Typed<'static>, TypeError> {
+ match self {
+ // TypedImproved::Pi(ctx, c, x, t, e) => Ok(Typed(
+ // rc(ExprF::Pi(
+ // x,
+ // t.into_normalized()?.embed(),
+ // e.into_normalized()?.embed(),
+ // )),
+ // Some(const_to_type(c)),
+ // ctx,
+ // PhantomData,
+ // )),
+ TypedImproved::Expr(e) => Ok(e),
+ }
+ }
+}
+
+#[derive(Debug, Clone)]
pub(crate) enum EnvItem {
Type(V<Label>, Type<'static>),
Value(Normalized<'static>),
@@ -190,6 +227,15 @@ impl TypecheckContext {
}
}
+impl PartialEq for TypecheckContext {
+ fn eq(&self, _: &Self) -> bool {
+ // don't count contexts when comparing stuff
+ // this is dirty but needed for now
+ true
+ }
+}
+impl Eq for TypecheckContext {}
+
fn function_check(a: Const, b: Const) -> Result<Const, ()> {
use dhall_core::Const::*;
match (a, b) {
@@ -420,7 +466,7 @@ fn mktype(
ctx: &TypecheckContext,
e: SubExpr<X, Normalized<'static>>,
) -> Result<Type<'static>, TypeError> {
- Ok(type_with(ctx, e)?.normalize().into_type())
+ Ok(type_with(ctx, e)?.into_typed()?.normalize_to_type())
}
fn into_simple_type<'a>(e: SubExpr<X, X>) -> Type<'a> {
@@ -445,7 +491,7 @@ enum Ret {
fn type_with(
ctx: &TypecheckContext,
e: SubExpr<X, Normalized<'static>>,
-) -> Result<Typed<'static>, TypeError> {
+) -> Result<TypedImproved, TypeError> {
use dhall_core::ExprF::*;
let mkerr = |msg: TypeMessage<'static>| TypeError::new(ctx, e.clone(), msg);
@@ -454,7 +500,7 @@ fn type_with(
Lam(x, t, b) => {
let t = mktype(ctx, t.clone())?;
let ctx2 = ctx.insert_type(x, t.clone());
- let b = type_with(&ctx2, b.clone())?;
+ let b = type_with(&ctx2, b.clone())?.into_typed()?;
Ok(RetExpr(Pi(
x.clone(),
t.embed()?,
@@ -469,13 +515,17 @@ fn type_with(
);
let ctx2 = ctx.insert_type(x, ta.clone());
- let tb = type_with(&ctx2, tb.clone())?;
+ let tb = mktype(&ctx2, tb.clone())?;
let kB = ensure_is_const!(
&tb.get_type()?,
TypeError::new(
&ctx2,
e.clone(),
- InvalidOutputType(tb.get_type_move()?.into_normalized()?),
+ InvalidOutputType(
+ tb.into_normalized()?
+ .get_type_move()?
+ .into_normalized()?
+ ),
),
);
@@ -484,11 +534,14 @@ fn type_with(
Err(()) => {
return Err(mkerr(NoDependentTypes(
ta.clone().into_normalized()?,
- tb.get_type_move()?.into_normalized()?,
+ tb.into_normalized()?
+ .get_type_move()?
+ .into_normalized()?,
)))
}
};
+ // return Ok(TypedImproved::Pi(ctx.clone(), k, x.clone(), ta, tb));
Ok(RetExpr(Const(k)))
}
Let(x, t, v, e) => {
@@ -498,28 +551,35 @@ fn type_with(
v.clone()
};
- let v = type_with(ctx, v)?.normalize();
- let e = type_with(&ctx.insert_value(x, v.clone()), e.clone())?;
+ let v = type_with(ctx, v)?.into_typed()?.normalize();
+ let e = type_with(&ctx.insert_value(x, v.clone()), e.clone())?
+ .into_typed()?;
Ok(RetType(e.get_type_move()?))
}
- Embed(p) => return Ok(p.clone().into()),
+ Embed(p) => return Ok(TypedImproved::Expr(p.clone().into())),
_ => type_last_layer(
ctx,
// Typecheck recursively all subexpressions
- e.as_ref()
- .traverse_ref_simple(|e| type_with(ctx, e.clone()))?,
+ e.as_ref().traverse_ref_simple(|e| {
+ Ok(type_with(ctx, e.clone())?.into_typed()?)
+ })?,
e.clone(),
),
}?;
match ret {
- RetExpr(ret) => Ok(Typed(
+ RetExpr(ret) => Ok(TypedImproved::Expr(Typed(
e,
Some(mktype(ctx, rc(ret))?),
ctx.clone(),
PhantomData,
- )),
- RetType(typ) => Ok(Typed(e, Some(typ), ctx.clone(), PhantomData)),
+ ))),
+ RetType(typ) => Ok(TypedImproved::Expr(Typed(
+ e,
+ Some(typ),
+ ctx.clone(),
+ PhantomData,
+ ))),
}
}
@@ -566,7 +626,7 @@ fn type_last_layer(
)))
}
Annot(x, t) => {
- let t = t.normalize().into_type();
+ let t = t.normalize_to_type();
ensure_equal!(
&t,
x.get_type()?,
@@ -600,7 +660,7 @@ fn type_last_layer(
Ok(RetType(y.get_type_move()?))
}
EmptyListLit(t) => {
- let t = t.normalize().into_type();
+ let t = t.normalize_to_type();
ensure_simple_type!(
t,
mkerr(InvalidListType(t.into_normalized()?)),
@@ -633,13 +693,17 @@ fn type_last_layer(
OldOptionalLit(None, t) => {
let t = t.normalize().embed();
let e = dhall::subexpr!(None t);
- Ok(RetType(type_with(ctx, e)?.get_type()?.into_owned()))
+ Ok(RetType(
+ type_with(ctx, e)?.into_typed()?.get_type()?.into_owned(),
+ ))
}
OldOptionalLit(Some(x), t) => {
let t = t.normalize().embed();
let x = x.normalize().embed();
let e = dhall::subexpr!(Some x : Optional t);
- Ok(RetType(type_with(ctx, e)?.get_type()?.into_owned()))
+ Ok(RetType(
+ type_with(ctx, e)?.into_typed()?.get_type()?.into_owned(),
+ ))
}
SomeLit(x) => {
let tx = x.get_type_move()?;
@@ -721,20 +785,23 @@ fn type_last_layer(
None => Err(mkerr(MissingRecordField(x, r))),
},
_ => {
- let r = r.normalize();
- match r.as_expr().as_ref() {
+ let r = r.normalize_to_type();
+ match r.as_normalized()?.as_expr().as_ref() {
UnionType(kts) => match kts.get(&x) {
// Constructor has type T -> < x: T, ... >
// TODO: use "_" instead of x
Some(Some(t)) => Ok(RetExpr(Pi(
x.clone(),
t.embed_absurd(),
- r.embed(),
+ r.into_normalized()?.embed(),
+ ))),
+ Some(None) => Ok(RetType(r)),
+ None => Err(mkerr(MissingUnionField(
+ x,
+ r.into_normalized()?,
))),
- Some(None) => Ok(RetType(r.into_type())),
- None => Err(mkerr(MissingUnionField(x, r))),
},
- _ => Err(mkerr(NotARecord(x, r))),
+ _ => Err(mkerr(NotARecord(x, r.into_normalized()?))),
}
}
},
@@ -793,7 +860,7 @@ fn type_of(
e: SubExpr<X, Normalized<'static>>,
) -> Result<Typed<'static>, TypeError> {
let ctx = TypecheckContext::new();
- let e = type_with(&ctx, e)?;
+ let e = type_with(&ctx, e)?.into_typed()?;
// Ensure the inferred type isn't SuperType
e.get_type()?.as_normalized()?;
Ok(e)