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-rw-r--r--dhall/src/lib.rs2
-rw-r--r--dhall/src/typecheck.rs406
2 files changed, 203 insertions, 205 deletions
diff --git a/dhall/src/lib.rs b/dhall/src/lib.rs
index 0270103..103fd29 100644
--- a/dhall/src/lib.rs
+++ b/dhall/src/lib.rs
@@ -14,6 +14,8 @@ mod dhall_type;
pub mod imports;
pub mod typecheck;
pub use crate::dhall_type::*;
+pub use dhall_generator::expr;
+pub use dhall_generator::subexpr;
pub use dhall_generator::Type;
pub use crate::imports::*;
diff --git a/dhall/src/typecheck.rs b/dhall/src/typecheck.rs
index 145de63..e63b032 100644
--- a/dhall/src/typecheck.rs
+++ b/dhall/src/typecheck.rs
@@ -6,7 +6,7 @@ use crate::normalize::normalize;
use dhall_core;
use dhall_core::context::Context;
use dhall_core::*;
-use dhall_generator::dhall_expr;
+use dhall_generator as dhall;
use self::TypeMessage::*;
@@ -112,31 +112,31 @@ where
go::<S, T>(&mut ctx, eL0, eR0)
}
-fn type_of_builtin<S>(b: Builtin) -> SubExpr<S, X> {
+fn type_of_builtin<S>(b: Builtin) -> Expr<S, X> {
use dhall_core::Builtin::*;
match b {
- Bool | Natural | Integer | Double | Text => dhall_expr!(Type),
- List | Optional => dhall_expr!(
+ Bool | Natural | Integer | Double | Text => dhall::expr!(Type),
+ List | Optional => dhall::expr!(
Type -> Type
),
- NaturalFold => dhall_expr!(
+ NaturalFold => dhall::expr!(
Natural ->
forall (natural: Type) ->
forall (succ: natural -> natural) ->
forall (zero: natural) ->
natural
),
- NaturalBuild => dhall_expr!(
+ NaturalBuild => dhall::expr!(
(forall (natural: Type) ->
forall (succ: natural -> natural) ->
forall (zero: natural) ->
natural) ->
Natural
),
- NaturalIsZero | NaturalEven | NaturalOdd => dhall_expr!(
+ NaturalIsZero | NaturalEven | NaturalOdd => dhall::expr!(
Natural -> Bool
),
- ListBuild => dhall_expr!(
+ ListBuild => dhall::expr!(
forall (a: Type) ->
(forall (list: Type) ->
forall (cons: a -> list -> list) ->
@@ -144,7 +144,7 @@ fn type_of_builtin<S>(b: Builtin) -> SubExpr<S, X> {
list) ->
List a
),
- ListFold => dhall_expr!(
+ ListFold => dhall::expr!(
forall (a: Type) ->
List a ->
forall (list: Type) ->
@@ -152,19 +152,19 @@ fn type_of_builtin<S>(b: Builtin) -> SubExpr<S, X> {
forall (nil: list) ->
list
),
- ListLength => dhall_expr!(forall (a: Type) -> List a -> Natural),
+ ListLength => dhall::expr!(forall (a: Type) -> List a -> Natural),
ListHead | ListLast => {
- dhall_expr!(forall (a: Type) -> List a -> Optional a)
+ dhall::expr!(forall (a: Type) -> List a -> Optional a)
}
- ListIndexed => dhall_expr!(
+ ListIndexed => dhall::expr!(
forall (a: Type) ->
List a ->
List { index: Natural, value: a }
),
- ListReverse => dhall_expr!(
+ ListReverse => dhall::expr!(
forall (a: Type) -> List a -> List a
),
- OptionalFold => dhall_expr!(
+ OptionalFold => dhall::expr!(
forall (a: Type) ->
Optional a ->
forall (optional: Type) ->
@@ -176,12 +176,29 @@ fn type_of_builtin<S>(b: Builtin) -> SubExpr<S, X> {
}
}
-/// Type-check an expression and return the expression'i type if type-checking
-/// suceeds or an error if type-checking fails
+fn ensure_equal<'a, S, F1, F2>(
+ x: &'a Expr<S, X>,
+ y: &'a Expr<S, X>,
+ mkerr: F1,
+ mkmsg: F2,
+) -> Result<(), TypeError<S>>
+where
+ S: std::fmt::Debug,
+ F1: FnOnce(TypeMessage<S>) -> TypeError<S>,
+ F2: FnOnce() -> TypeMessage<S>,
+{
+ if prop_equal(x, y) {
+ Ok(())
+ } else {
+ Err(mkerr(mkmsg()))
+ }
+}
+
+/// Type-check an expression and return the expression's type if type-checking
+/// succeeds or an error if type-checking fails
///
-/// `type_with` does not necessarily normalize the type since full normalization
-/// is not necessary for just type-checking. If you actually care about the
-/// returned type then you may want to `normalize` it afterwards.
+/// `type_with` normalizes the type since while type-checking. It expects the
+/// context to contain only normalized expressions.
pub fn type_with<S>(
ctx: &Context<Label, SubExpr<S, X>>,
e: SubExpr<S, X>,
@@ -205,31 +222,25 @@ where
_ => Err(mkerr(msg)),
};
- match e.as_ref() {
- Const(c) => axiom(*c).map(Const),
- Var(V(x, n)) => {
- return ctx
- .lookup(x, *n)
- .cloned()
- .ok_or_else(|| mkerr(UnboundVariable))
- }
- Lam(x, tA, b) => {
+ let ret = match e.as_ref() {
+ Lam(x, t, b) => {
+ let t2 = normalize(SubExpr::clone(t));
let ctx2 = ctx
- .insert(x.clone(), tA.clone())
+ .insert(x.clone(), t2.clone())
.map(|e| shift(1, &V(x.clone(), 0), e));
let tB = type_with(&ctx2, b.clone())?;
- let p = rc(Pi(x.clone(), tA.clone(), tB));
- let _ = type_with(ctx, p.clone())?;
- return Ok(p);
+ let _ = type_with(ctx, rc(Pi(x.clone(), t.clone(), tB.clone())))?;
+ Ok(Pi(x.clone(), t2, tB))
}
Pi(x, tA, tB) => {
- let tA2 = normalized_type_with(ctx, tA.clone())?;
- let kA = ensure_const(&tA2, InvalidInputType(tA.clone()))?;
+ let ttA = type_with(ctx, tA.clone())?;
+ let tA = normalize(SubExpr::clone(tA));
+ let kA = ensure_const(&ttA, InvalidInputType(tA.clone()))?;
let ctx2 = ctx
.insert(x.clone(), tA.clone())
.map(|e| shift(1, &V(x.clone(), 0), e));
- let tB = normalized_type_with(&ctx2, tB.clone())?;
+ let tB = type_with(&ctx2, tB.clone())?;
let kB = match tB.as_ref() {
Const(k) => *k,
_ => {
@@ -246,33 +257,6 @@ where
Ok(_) => Ok(Const(kB)),
}
}
- App(f, args) => {
- // Recurse on args
- let (a, tf) = match args.split_last() {
- None => return type_with(ctx, f.clone()),
- Some((a, args)) => (
- a,
- normalized_type_with(
- ctx,
- rc(App(f.clone(), args.to_vec())),
- )?,
- ),
- };
- let (x, tA, tB) = match tf.as_ref() {
- Pi(x, tA, tB) => (x, tA, tB),
- _ => {
- return Err(mkerr(NotAFunction(f.clone(), tf)));
- }
- };
- let tA = normalize(SubExpr::clone(tA));
- let tA2 = normalized_type_with(ctx, a.clone())?;
- if prop_equal(tA.as_ref(), tA2.as_ref()) {
- let vx0 = &V(x.clone(), 0);
- return Ok(subst_shift(vx0, &a, &tB));
- } else {
- Err(mkerr(TypeMismatch(f.clone(), tA, a.clone(), tA2)))
- }
- }
Let(f, mt, r, b) => {
let r = if let Some(t) = mt {
rc(Annot(SubExpr::clone(r), SubExpr::clone(t)))
@@ -281,14 +265,14 @@ where
};
let tR = type_with(ctx, r)?;
- let ttR = normalized_type_with(ctx, tR.clone())?;
+ let ttR = type_with(ctx, tR.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 ctx2 = ctx.insert(f.clone(), tR.clone());
let tB = type_with(&ctx2, b.clone())?;
- let ttB = normalized_type_with(ctx, tB.clone())?;
+ let ttB = type_with(ctx, tB.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()))?;
@@ -297,162 +281,174 @@ where
return Err(mkerr(NoDependentLet(tR, tB)));
}
- return Ok(tB);
- }
- Annot(x, t) => {
- // This is mainly just to check that `t` is not `Kind`
- let _ = type_with(ctx, t.clone())?;
-
- let t2 = normalized_type_with(ctx, x.clone())?;
- let t = normalize(t.clone());
- if prop_equal(t.as_ref(), t2.as_ref()) {
- return Ok(t.clone());
- } else {
- Err(mkerr(AnnotMismatch(x.clone(), t, t2)))
- }
+ Ok(tB.unroll())
}
- BoolIf(x, y, z) => {
- let tx = normalized_type_with(ctx, x.clone())?;
- match tx.as_ref() {
- Builtin(Bool) => {}
- _ => {
- return Err(mkerr(InvalidPredicate(x.clone(), tx)));
+ _ => match e
+ .as_ref()
+ .traverse_ref_simple(|e| Ok((e, type_with(ctx, e.clone())?)))?
+ {
+ Lam(_, _, _) => unreachable!(),
+ Pi(_, _, _) => unreachable!(),
+ Let(_, _, _, _) => unreachable!(),
+ Const(c) => axiom(c).map(Const),
+ Var(V(x, n)) => match ctx.lookup(&x, n) {
+ Some(e) => Ok(e.unroll()),
+ None => Err(mkerr(UnboundVariable)),
+ },
+ App((f, mut tf), args) => {
+ let mut iter = args.into_iter();
+ let mut seen_args: Vec<SubExpr<_, _>> = vec![];
+ while let Some((a, ta)) = iter.next() {
+ seen_args.push(a.clone());
+ let (x, tx, tb) = match tf.as_ref() {
+ Pi(x, tx, tb) => (x, tx, tb),
+ _ => {
+ return Err(mkerr(NotAFunction(
+ rc(App(f.clone(), seen_args)),
+ tf,
+ )));
+ }
+ };
+ ensure_equal(tx.as_ref(), ta.as_ref(), mkerr, || {
+ TypeMismatch(
+ rc(App(f.clone(), seen_args.clone())),
+ tx.clone(),
+ a.clone(),
+ ta.clone(),
+ )
+ })?;
+ tf = normalize(subst_shift(&V(x.clone(), 0), &a, &tb));
}
+ Ok(tf.unroll())
}
- let ty = normalized_type_with(ctx, y.clone())?;
- let tty = normalized_type_with(ctx, ty.clone())?;
- ensure_is_type(
- tty.clone(),
- IfBranchMustBeTerm(true, y.clone(), ty.clone(), tty.clone()),
- )?;
+ Annot((x, tx), (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())
+ }
+ BoolIf((x, tx), (y, ty), (z, tz)) => {
+ ensure_equal(tx.as_ref(), &Builtin(Bool), mkerr, || {
+ InvalidPredicate(x.clone(), tx.clone())
+ })?;
+ let tty = type_with(ctx, ty.clone())?;
+ ensure_is_type(
+ tty.clone(),
+ IfBranchMustBeTerm(
+ true,
+ y.clone(),
+ ty.clone(),
+ tty.clone(),
+ ),
+ )?;
- let tz = normalized_type_with(ctx, z.clone())?;
- let ttz = normalized_type_with(ctx, tz.clone())?;
- ensure_is_type(
- ttz.clone(),
- IfBranchMustBeTerm(false, z.clone(), tz.clone(), ttz.clone()),
- )?;
+ let ttz = type_with(ctx, tz.clone())?;
+ ensure_is_type(
+ ttz.clone(),
+ IfBranchMustBeTerm(
+ false,
+ z.clone(),
+ tz.clone(),
+ ttz.clone(),
+ ),
+ )?;
- if !prop_equal(ty.as_ref(), tz.as_ref()) {
- return Err(mkerr(IfBranchMismatch(
- y.clone(),
- z.clone(),
- ty,
- tz,
- )));
+ ensure_equal(ty.as_ref(), tz.as_ref(), mkerr, || {
+ IfBranchMismatch(
+ y.clone(),
+ z.clone(),
+ ty.clone(),
+ tz.clone(),
+ )
+ })?;
+ Ok(ty.unroll())
}
- return Ok(ty);
- }
- EmptyListLit(t) => {
- let s = normalized_type_with(ctx, t.clone())?;
- ensure_is_type(s, InvalidListType(t.clone()))?;
- let t = normalize(SubExpr::clone(t));
- return Ok(dhall_expr!(List t));
- }
- NEListLit(xs) => {
- let mut iter = xs.iter().enumerate();
- let (_, first_x) = iter.next().unwrap();
- let t = type_with(ctx, first_x.clone())?;
-
- let s = normalized_type_with(ctx, t.clone())?;
- ensure_is_type(s, InvalidListType(t.clone()))?;
- let t = normalize(t);
- for (i, x) in iter {
- let t2 = normalized_type_with(ctx, x.clone())?;
- if !prop_equal(t.as_ref(), t2.as_ref()) {
- return Err(mkerr(InvalidListElement(i, t, x.clone(), t2)));
+ EmptyListLit((t, tt)) => {
+ ensure_is_type(tt, InvalidListType(t.clone()))?;
+ let t = normalize(SubExpr::clone(t));
+ Ok(dhall::expr!(List t))
+ }
+ NEListLit(xs) => {
+ let mut iter = xs.into_iter().enumerate();
+ let (_, (_, t)) = iter.next().unwrap();
+ let s = type_with(ctx, t.clone())?;
+ ensure_is_type(s, InvalidListType(t.clone()))?;
+ for (i, (y, ty)) in iter {
+ ensure_equal(t.as_ref(), ty.as_ref(), mkerr, || {
+ InvalidListElement(i, t.clone(), y.clone(), ty.clone())
+ })?;
}
+ Ok(dhall::expr!(List t))
}
- return Ok(dhall_expr!(List t));
- }
- EmptyOptionalLit(t) => {
- let s = normalized_type_with(ctx, t.clone())?;
- ensure_is_type(s, InvalidOptionalType(t.clone()))?;
- let t = normalize(t.clone());
- return Ok(dhall_expr!(Optional t));
- }
- NEOptionalLit(x) => {
- let t: SubExpr<_, _> = type_with(ctx, x.clone())?;
- let s = normalized_type_with(ctx, t.clone())?;
- ensure_is_type(s, InvalidOptionalType(t.clone()))?;
- let t = normalize(t);
- return Ok(dhall_expr!(Optional t));
- }
- RecordType(kts) => {
- for (k, t) in kts {
- let s = normalized_type_with(ctx, t.clone())?;
- ensure_is_type(s, InvalidFieldType(k.clone(), t.clone()))?;
+ EmptyOptionalLit((t, tt)) => {
+ ensure_is_type(tt, InvalidOptionalType(t.clone()))?;
+ let t = normalize(t.clone());
+ Ok(dhall::expr!(Optional t))
}
- Ok(Const(Type))
- }
- RecordLit(kvs) => {
- let kts = kvs
- .iter()
- .map(|(k, v)| {
- let t = type_with(ctx, v.clone())?;
- let s = normalized_type_with(ctx, t.clone())?;
- ensure_is_type(s, InvalidField(k.clone(), v.clone()))?;
- Ok((k.clone(), t))
- })
- .collect::<Result<_, _>>()?;
- Ok(RecordType(kts))
- }
- Field(r, x) => {
- let t = normalized_type_with(ctx, r.clone())?;
- match t.as_ref() {
- RecordType(kts) => {
- return kts.get(x).cloned().ok_or_else(|| {
- mkerr(MissingField(x.clone(), t.clone()))
- })
+ NEOptionalLit((_, t)) => {
+ let s = type_with(ctx, t.clone())?;
+ ensure_is_type(s, InvalidOptionalType(t.clone()))?;
+ Ok(dhall::expr!(Optional t))
+ }
+ RecordType(kts) => {
+ for (k, (t, tt)) in kts {
+ ensure_is_type(tt, InvalidFieldType(k.clone(), t.clone()))?;
}
- _ => Err(mkerr(NotARecord(x.clone(), r.clone(), t.clone()))),
+ Ok(Const(Type))
}
- }
- Builtin(b) => return Ok(type_of_builtin(*b)),
- BoolLit(_) => Ok(Builtin(Bool)),
- NaturalLit(_) => Ok(Builtin(Natural)),
- IntegerLit(_) => Ok(Builtin(Integer)),
- DoubleLit(_) => Ok(Builtin(Double)),
- TextLit(_) => Ok(Builtin(Text)),
- BinOp(o, l, r) => {
- let t = match o {
- BoolAnd => Bool,
- BoolOr => Bool,
- BoolEQ => Bool,
- BoolNE => Bool,
- NaturalPlus => Natural,
- NaturalTimes => Natural,
- TextAppend => Text,
- _ => panic!("Unimplemented typecheck case: {:?}", e),
- };
- let tl = normalized_type_with(ctx, l.clone())?;
- match tl.as_ref() {
- Builtin(lt) if *lt == t => {}
- _ => return Err(mkerr(BinOpTypeMismatch(*o, l.clone(), tl))),
+ RecordLit(kvs) => {
+ let kts = kvs
+ .into_iter()
+ .map(|(k, (v, t))| {
+ let s = type_with(ctx, t.clone())?;
+ ensure_is_type(s, InvalidField(k.clone(), v.clone()))?;
+ Ok((k.clone(), t))
+ })
+ .collect::<Result<_, _>>()?;
+ Ok(RecordType(kts))
}
+ Field((r, tr), x) => match tr.as_ref() {
+ RecordType(kts) => match kts.get(&x) {
+ Some(e) => Ok(e.unroll()),
+ None => Err(mkerr(MissingField(x.clone(), tr.clone()))),
+ },
+ _ => Err(mkerr(NotARecord(x.clone(), r.clone(), tr.clone()))),
+ },
+ Builtin(b) => Ok(type_of_builtin(b)),
+ BoolLit(_) => Ok(Builtin(Bool)),
+ NaturalLit(_) => Ok(Builtin(Natural)),
+ IntegerLit(_) => Ok(Builtin(Integer)),
+ DoubleLit(_) => Ok(Builtin(Double)),
+ // TODO: check type of interpolations
+ TextLit(_) => Ok(Builtin(Text)),
+ BinOp(o, (l, tl), (r, tr)) => {
+ let t = Builtin(match o {
+ BoolAnd => Bool,
+ BoolOr => Bool,
+ BoolEQ => Bool,
+ BoolNE => Bool,
+ NaturalPlus => Natural,
+ NaturalTimes => Natural,
+ TextAppend => Text,
+ _ => panic!("Unimplemented typecheck case: {:?}", e),
+ });
- let tr = normalized_type_with(ctx, r.clone())?;
- match tr.as_ref() {
- Builtin(rt) if *rt == t => {}
- _ => return Err(mkerr(BinOpTypeMismatch(*o, r.clone(), tr))),
- }
+ ensure_equal(tl.as_ref(), &t, mkerr, || {
+ BinOpTypeMismatch(o, l.clone(), tl.clone())
+ })?;
- Ok(Builtin(t))
- }
- Embed(p) => match *p {},
- _ => panic!("Unimplemented typecheck case: {:?}", e),
- }
- .map(rc)
-}
+ ensure_equal(tr.as_ref(), &t, mkerr, || {
+ BinOpTypeMismatch(o, r.clone(), tr.clone())
+ })?;
-pub fn normalized_type_with<S>(
- ctx: &Context<Label, SubExpr<S, X>>,
- e: SubExpr<S, X>,
-) -> Result<SubExpr<S, X>, TypeError<S>>
-where
- S: ::std::fmt::Debug + Clone,
-{
- Ok(normalize(type_with(ctx, e)?))
+ Ok(t)
+ }
+ Embed(p) => match p {},
+ _ => panic!("Unimplemented typecheck case: {:?}", e),
+ },
+ }?;
+ Ok(rc(ret))
}
/// `typeOf` is the same as `type_with` with an empty context, meaning that the
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-27 03:42:58 +0000