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-rw-r--r--dhall/src/expr.rs2
-rw-r--r--dhall/src/normalize.rs5
-rw-r--r--dhall/src/typecheck.rs239
3 files changed, 135 insertions, 111 deletions
diff --git a/dhall/src/expr.rs b/dhall/src/expr.rs
index cc7f064..831fbc5 100644
--- a/dhall/src/expr.rs
+++ b/dhall/src/expr.rs
@@ -15,7 +15,7 @@ pub struct Typed(pub(crate) SubExpr<X, X>, pub(crate) Type);
pub type Type = SubExpr<X, X>;
#[derive(Debug, Clone)]
-pub struct Normalized(pub(crate) SubExpr<X, X>);
+pub struct Normalized(pub(crate) SubExpr<X, X>, pub(crate) Type);
impl PartialEq for Parsed {
fn eq(&self, other: &Self) -> bool {
diff --git a/dhall/src/normalize.rs b/dhall/src/normalize.rs
index 8ed2136..f9633fb 100644
--- a/dhall/src/normalize.rs
+++ b/dhall/src/normalize.rs
@@ -6,10 +6,7 @@ use std::fmt;
impl Typed {
pub fn normalize(self) -> Normalized {
- Normalized(normalize(self.0))
- }
- pub fn get_type(&self) -> &Type {
- &self.1
+ Normalized(normalize(self.0), self.1)
}
}
diff --git a/dhall/src/typecheck.rs b/dhall/src/typecheck.rs
index f5dbbbf..d62fe5a 100644
--- a/dhall/src/typecheck.rs
+++ b/dhall/src/typecheck.rs
@@ -3,7 +3,6 @@ use std::collections::HashSet;
use std::fmt;
use crate::expr::*;
-use crate::normalize::normalize;
use dhall_core;
use dhall_core::context::Context;
use dhall_core::*;
@@ -21,6 +20,16 @@ impl Resolved {
Ok(Typed(self.0, typ))
}
}
+impl Typed {
+ pub fn get_type(&self) -> &Type {
+ &self.1
+ }
+}
+impl Normalized {
+ pub fn get_type(&self) -> &Type {
+ &self.1
+ }
+}
fn axiom<S>(c: Const) -> Result<Const, TypeError<S>> {
use dhall_core::Const::*;
@@ -231,23 +240,29 @@ pub fn type_with(
_ => Err(mkerr(msg)),
};
+ enum Ret {
+ ErrRet(TypeError<X>),
+ OkNormalized(Normalized),
+ OkRet(Expr<X, X>),
+ }
+ use Ret::*;
let ret = match e.as_ref() {
Lam(x, t, b) => {
- let t2 = normalize(SubExpr::clone(t));
+ let t2 = type_with(ctx, t.clone())?.normalize();
let ctx2 = ctx
- .insert(x.clone(), t2.clone())
+ .insert(x.clone(), t2.0.clone())
.map(|e| shift(1, &V(x.clone(), 0), e));
let tB = type_with(&ctx2, b.clone())?.1;
let _ = type_with(ctx, rc(Pi(x.clone(), t.clone(), tB.clone())))?.1;
- Ok(Pi(x.clone(), t2, tB))
+ OkRet(Pi(x.clone(), t2.0, tB))
}
Pi(x, tA, tB) => {
- let ttA = type_with(ctx, tA.clone())?.1;
- let tA = normalize(SubExpr::clone(tA));
- let kA = ensure_const(&ttA, InvalidInputType(tA.clone()))?;
+ let tA = type_with(ctx, tA.clone())?.normalize();
+ let kA =
+ ensure_const(tA.get_type(), InvalidInputType(tA.0.clone()))?;
let ctx2 = ctx
- .insert(x.clone(), tA.clone())
+ .insert(x.clone(), tA.0.clone())
.map(|e| shift(1, &V(x.clone(), 0), e));
let tB = type_with(&ctx2, tB.clone())?.1;
let kB = match tB.as_ref() {
@@ -262,8 +277,8 @@ pub fn type_with(
};
match rule(kA, kB) {
- Err(()) => Err(mkerr(NoDependentTypes(tA.clone(), tB))),
- Ok(_) => Ok(Const(kB)),
+ Err(()) => ErrRet(mkerr(NoDependentTypes(tA.0.clone(), tB))),
+ Ok(_) => OkRet(Const(kB)),
}
}
Let(f, mt, r, b) => {
@@ -273,24 +288,33 @@ pub fn type_with(
SubExpr::clone(r)
};
- let tR = type_with(ctx, r)?.1;
- let ttR = type_with(ctx, tR.clone())?.1;
+ let r = type_with(ctx, r)?;
+ let tr = type_with(ctx, r.get_type().clone())?;
// Don't bother to provide a `let`-specific version of this error
// message because this should never happen anyway
- let kR = ensure_const(&ttR, InvalidInputType(tR.clone()))?;
+ let kR = ensure_const(
+ tr.get_type(),
+ InvalidInputType(r.get_type().clone()),
+ )?;
- let ctx2 = ctx.insert(f.clone(), tR.clone());
- let tB = type_with(&ctx2, b.clone())?.1;
- let ttB = type_with(ctx, tB.clone())?.1;
+ let ctx2 = ctx.insert(f.clone(), r.get_type().clone());
+ let b = type_with(&ctx2, b.clone())?;
+ let tb = type_with(ctx, b.get_type().clone())?;
// Don't bother to provide a `let`-specific version of this error
// message because this should never happen anyway
- let kB = ensure_const(&ttB, InvalidOutputType(tB.clone()))?;
+ let kB = ensure_const(
+ tb.get_type(),
+ InvalidOutputType(b.get_type().clone()),
+ )?;
if let Err(()) = rule(kR, kB) {
- return Err(mkerr(NoDependentLet(tR, tB)));
+ return Err(mkerr(NoDependentLet(
+ r.get_type().clone(),
+ b.get_type().clone(),
+ )));
}
- Ok(tB.unroll())
+ OkRet(b.get_type().unroll())
}
_ => match e
.as_ref()
@@ -299,84 +323,85 @@ pub fn type_with(
Lam(_, _, _) => unreachable!(),
Pi(_, _, _) => unreachable!(),
Let(_, _, _, _) => unreachable!(),
- Const(c) => axiom(c).map(Const),
+ Const(c) => OkRet(Const(axiom(c)?)),
Var(V(x, n)) => match ctx.lookup(&x, n) {
- Some(e) => Ok(e.unroll()),
- None => Err(mkerr(UnboundVariable)),
+ Some(e) => OkRet(e.unroll()),
+ None => ErrRet(mkerr(UnboundVariable)),
},
- App(Typed(f, mut tf), args) => {
+ App(f, args) => {
let mut iter = args.into_iter();
let mut seen_args: Vec<SubExpr<_, _>> = vec![];
+ let mut tf = type_with(ctx, f.get_type().clone())?.normalize();
while let Some(Typed(a, ta)) = iter.next() {
seen_args.push(a.clone());
- let (x, tx, tb) = match tf.as_ref() {
+ let (x, tx, tb) = match tf.0.as_ref() {
Pi(x, tx, tb) => (x, tx, tb),
_ => {
return Err(mkerr(NotAFunction(
- rc(App(f.clone(), seen_args)),
+ rc(App(f.0.clone(), seen_args)),
tf,
)));
}
};
ensure_equal(tx.as_ref(), ta.as_ref(), mkerr, || {
TypeMismatch(
- rc(App(f.clone(), seen_args.clone())),
+ rc(App(f.0.clone(), seen_args.clone())),
tx.clone(),
a.clone(),
ta.clone(),
)
})?;
- tf = normalize(subst_shift(&V(x.clone(), 0), &a, &tb));
+ tf =
+ type_with(ctx, subst_shift(&V(x.clone(), 0), &a, &tb))?
+ .normalize();
}
- Ok(tf.unroll())
+ OkNormalized(tf)
}
- Annot(Typed(x, tx), Typed(t, _)) => {
- let t = normalize(t.clone());
- ensure_equal(t.as_ref(), tx.as_ref(), mkerr, || {
- AnnotMismatch(x.clone(), t.clone(), tx.clone())
- })?;
- Ok(t.unroll())
+ Annot(x, t) => {
+ let t = t.normalize();
+ ensure_equal(
+ t.0.as_ref(),
+ x.get_type().as_ref(),
+ mkerr,
+ || AnnotMismatch(x.clone(), t.clone()),
+ )?;
+ OkNormalized(t)
}
- BoolIf(Typed(x, tx), Typed(y, ty), Typed(z, tz)) => {
- ensure_equal(tx.as_ref(), &Builtin(Bool), mkerr, || {
- InvalidPredicate(x.clone(), tx.clone())
- })?;
- let tty = type_with(ctx, ty.clone())?.1;
+ BoolIf(x, y, z) => {
+ ensure_equal(
+ x.get_type().as_ref(),
+ &Builtin(Bool),
+ mkerr,
+ || InvalidPredicate(x.clone()),
+ )?;
+ let ty = type_with(ctx, y.get_type().clone())?.normalize();
ensure_is_type(
- tty.clone(),
- IfBranchMustBeTerm(
- true,
- y.clone(),
- ty.clone(),
- tty.clone(),
- ),
+ ty.get_type().clone(),
+ IfBranchMustBeTerm(true, y.clone()),
)?;
- let ttz = type_with(ctx, tz.clone())?.1;
+ let tz = type_with(ctx, z.get_type().clone())?.normalize();
ensure_is_type(
- ttz.clone(),
- IfBranchMustBeTerm(
- false,
- z.clone(),
- tz.clone(),
- ttz.clone(),
- ),
+ tz.get_type().clone(),
+ IfBranchMustBeTerm(false, z.clone()),
)?;
- ensure_equal(ty.as_ref(), tz.as_ref(), mkerr, || {
- IfBranchMismatch(
- y.clone(),
- z.clone(),
- ty.clone(),
- tz.clone(),
- )
- })?;
- Ok(ty.unroll())
+ ensure_equal(
+ y.get_type().as_ref(),
+ z.get_type().as_ref(),
+ mkerr,
+ || IfBranchMismatch(y.clone(), z.clone()),
+ )?;
+
+ OkNormalized(ty)
}
- EmptyListLit(Typed(t, tt)) => {
- ensure_is_type(tt.clone(), InvalidListType(t.clone()))?;
- let t = Typed(t, tt).normalize().0;
- Ok(dhall::expr!(List t))
+ EmptyListLit(t) => {
+ ensure_is_type(
+ t.get_type().clone(),
+ InvalidListType(t.0.clone()),
+ )?;
+ let t = t.normalize().0;
+ OkRet(dhall::expr!(List t))
}
NEListLit(xs) => {
let mut iter = xs.into_iter().enumerate();
@@ -388,23 +413,26 @@ pub fn type_with(
InvalidListElement(i, t.clone(), y.clone(), ty.clone())
})?;
}
- Ok(dhall::expr!(List t))
+ OkRet(dhall::expr!(List t))
}
- EmptyOptionalLit(Typed(t, tt)) => {
- ensure_is_type(tt, InvalidOptionalType(t.clone()))?;
- let t = normalize(t.clone());
- Ok(dhall::expr!(Optional t))
+ EmptyOptionalLit(t) => {
+ ensure_is_type(
+ t.get_type().clone(),
+ InvalidOptionalType(t.0.clone()),
+ )?;
+ let t = t.normalize().0;
+ OkRet(dhall::expr!(Optional t))
}
NEOptionalLit(Typed(_, t)) => {
let s = type_with(ctx, t.clone())?.1;
ensure_is_type(s, InvalidOptionalType(t.clone()))?;
- Ok(dhall::expr!(Optional t))
+ OkRet(dhall::expr!(Optional t))
}
RecordType(kts) => {
for (k, Typed(t, tt)) in kts {
ensure_is_type(tt, InvalidFieldType(k.clone(), t.clone()))?;
}
- Ok(Const(Type))
+ OkRet(Const(Type))
}
RecordLit(kvs) => {
let kts = kvs
@@ -415,23 +443,23 @@ pub fn type_with(
Ok((k.clone(), t))
})
.collect::<Result<_, _>>()?;
- Ok(RecordType(kts))
+ OkRet(RecordType(kts))
}
- Field(Typed(r, tr), x) => match tr.as_ref() {
+ Field(r, x) => match r.get_type().as_ref() {
RecordType(kts) => match kts.get(&x) {
- Some(e) => Ok(e.unroll()),
- None => Err(mkerr(MissingField(x.clone(), tr.clone()))),
+ Some(e) => OkRet(e.unroll()),
+ None => ErrRet(mkerr(MissingField(x.clone(), r.clone()))),
},
- _ => Err(mkerr(NotARecord(x.clone(), r.clone(), tr.clone()))),
+ _ => ErrRet(mkerr(NotARecord(x.clone(), r.clone()))),
},
- Builtin(b) => Ok(type_of_builtin(b)),
- BoolLit(_) => Ok(Builtin(Bool)),
- NaturalLit(_) => Ok(Builtin(Natural)),
- IntegerLit(_) => Ok(Builtin(Integer)),
- DoubleLit(_) => Ok(Builtin(Double)),
+ Builtin(b) => OkRet(type_of_builtin(b)),
+ BoolLit(_) => OkRet(Builtin(Bool)),
+ NaturalLit(_) => OkRet(Builtin(Natural)),
+ IntegerLit(_) => OkRet(Builtin(Integer)),
+ DoubleLit(_) => OkRet(Builtin(Double)),
// TODO: check type of interpolations
- TextLit(_) => Ok(Builtin(Text)),
- BinOp(o, Typed(l, tl), Typed(r, tr)) => {
+ TextLit(_) => OkRet(Builtin(Text)),
+ BinOp(o, l, r) => {
let t = Builtin(match o {
BoolAnd => Bool,
BoolOr => Bool,
@@ -443,21 +471,25 @@ pub fn type_with(
_ => panic!("Unimplemented typecheck case: {:?}", e),
});
- ensure_equal(tl.as_ref(), &t, mkerr, || {
- BinOpTypeMismatch(o, l.clone(), tl.clone())
+ ensure_equal(l.get_type().as_ref(), &t, mkerr, || {
+ BinOpTypeMismatch(o, l.clone())
})?;
- ensure_equal(tr.as_ref(), &t, mkerr, || {
- BinOpTypeMismatch(o, r.clone(), tr.clone())
+ ensure_equal(r.get_type().as_ref(), &t, mkerr, || {
+ BinOpTypeMismatch(o, r.clone())
})?;
- Ok(t)
+ OkRet(t)
}
Embed(p) => match p {},
_ => panic!("Unimplemented typecheck case: {:?}", e),
},
- }?;
- Ok(Typed(e, rc(ret)))
+ };
+ match ret {
+ OkRet(ret) => Ok(Typed(e, rc(ret))),
+ OkNormalized(ret) => Ok(Typed(e, ret.0)),
+ ErrRet(e) => Err(e),
+ }
}
/// `typeOf` is the same as `type_with` with an empty context, meaning that the
@@ -474,23 +506,18 @@ pub enum TypeMessage<S> {
UnboundVariable,
InvalidInputType(SubExpr<S, X>),
InvalidOutputType(SubExpr<S, X>),
- NotAFunction(SubExpr<S, X>, SubExpr<S, X>),
+ NotAFunction(SubExpr<S, X>, Normalized),
TypeMismatch(SubExpr<S, X>, SubExpr<S, X>, SubExpr<S, X>, SubExpr<S, X>),
- AnnotMismatch(SubExpr<S, X>, SubExpr<S, X>, SubExpr<S, X>),
+ AnnotMismatch(Typed, Normalized),
Untyped,
InvalidListElement(usize, SubExpr<S, X>, SubExpr<S, X>, SubExpr<S, X>),
InvalidListType(SubExpr<S, X>),
InvalidOptionalElement(SubExpr<S, X>, SubExpr<S, X>, SubExpr<S, X>),
InvalidOptionalLiteral(usize),
InvalidOptionalType(SubExpr<S, X>),
- InvalidPredicate(SubExpr<S, X>, SubExpr<S, X>),
- IfBranchMismatch(
- SubExpr<S, X>,
- SubExpr<S, X>,
- SubExpr<S, X>,
- SubExpr<S, X>,
- ),
- IfBranchMustBeTerm(bool, SubExpr<S, X>, SubExpr<S, X>, SubExpr<S, X>),
+ InvalidPredicate(Typed),
+ IfBranchMismatch(Typed, Typed),
+ IfBranchMustBeTerm(bool, Typed),
InvalidField(Label, SubExpr<S, X>),
InvalidFieldType(Label, SubExpr<S, X>),
InvalidAlternative(Label, SubExpr<S, X>),
@@ -505,9 +532,9 @@ pub enum TypeMessage<S> {
HandlerInputTypeMismatch(Label, SubExpr<S, X>, SubExpr<S, X>),
HandlerOutputTypeMismatch(Label, SubExpr<S, X>, SubExpr<S, X>),
HandlerNotAFunction(Label, SubExpr<S, X>),
- NotARecord(Label, SubExpr<S, X>, SubExpr<S, X>),
- MissingField(Label, SubExpr<S, X>),
- BinOpTypeMismatch(BinOp, SubExpr<S, X>, SubExpr<S, X>),
+ NotARecord(Label, Typed),
+ MissingField(Label, Typed),
+ BinOpTypeMismatch(BinOp, Typed),
NoDependentLet(SubExpr<S, X>, SubExpr<S, X>),
NoDependentTypes(SubExpr<S, X>, SubExpr<S, X>),
}