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authorNadrieril2019-04-30 18:52:39 +0200
committerNadrieril2019-04-30 18:52:39 +0200
commitcc96566758f062bb2e1e7767009c3e709c0678b6 (patch)
tree2e61207c04c4a074facebf51452875950f21da5c /dhall/src
parentba0c760e9dc30a4babf9b76860153aa05d16e9eb (diff)
Avoid some rewrapping of thunks
Diffstat (limited to '')
-rw-r--r--dhall/src/normalize.rs83
-rw-r--r--dhall/src/typecheck.rs4
2 files changed, 51 insertions, 36 deletions
diff --git a/dhall/src/normalize.rs b/dhall/src/normalize.rs
index c89e147..f2bae80 100644
--- a/dhall/src/normalize.rs
+++ b/dhall/src/normalize.rs
@@ -163,7 +163,7 @@ fn apply_builtin(b: Builtin, args: Vec<Value>) -> Value {
[_, NEListLit(xs), _, cons, nil] => {
let mut v = nil;
for x in xs.into_iter().rev() {
- v = cons.clone().app(x.normalize_whnf().clone()).app(v);
+ v = cons.clone().app_thunk(x).app(v);
}
v
}
@@ -197,7 +197,7 @@ fn apply_builtin(b: Builtin, args: Vec<Value>) -> Value {
nothing
},
[_, NEOptionalLit(x), _, just, _] => {
- just.app(x.normalize_whnf().clone())
+ just.app_thunk(x)
}
),
NaturalBuild => improved_slice_patterns::match_vec!(args;
@@ -678,43 +678,59 @@ impl Value {
/// Apply to a value
pub(crate) fn app(self, val: Value) -> Value {
- match (self, val) {
- (Value::Lam(x, _, e), val) => {
- let val = Typed(
- Thunk::from_whnf(val),
- None,
- std::marker::PhantomData,
- );
+ self.app_thunk(val.into_thunk())
+ }
+
+ /// Apply to a thunk
+ pub(crate) fn app_thunk(self, th: Thunk) -> Value {
+ // If nothing else matches, convert to Expr
+ let fallback = |f: Value, a: Thunk| {
+ Value::Expr(rc(ExprF::App(
+ f.normalize_to_expr(),
+ a.normalize_whnf().normalize_to_expr(),
+ )))
+ };
+
+ match self {
+ Value::Lam(x, _, e) => {
+ let val = Typed(th, None, std::marker::PhantomData);
e.subst_shift(&V(x, 0), &val).normalize_whnf().clone()
}
- (Value::AppliedBuiltin(b, mut args), val) => {
- args.push(val);
+ Value::AppliedBuiltin(b, mut args) => {
+ args.push(th.normalize_whnf().clone());
apply_builtin(b, args)
}
- (Value::OptionalSomeClosure(_), val) => {
- Value::NEOptionalLit(Thunk::from_whnf(val))
- }
- (Value::ListConsClosure(t, None), val) => {
- Value::ListConsClosure(t, Some(Thunk::from_whnf(val)))
+ Value::OptionalSomeClosure(_) => Value::NEOptionalLit(th),
+ Value::ListConsClosure(t, None) => {
+ Value::ListConsClosure(t, Some(th))
}
- (Value::ListConsClosure(_, Some(x)), Value::EmptyListLit(_)) => {
- Value::NEListLit(vec![x])
- }
- (Value::ListConsClosure(_, Some(x)), Value::NEListLit(mut xs)) => {
- xs.insert(0, x);
- Value::NEListLit(xs)
- }
- (Value::NaturalSuccClosure, Value::NaturalLit(n)) => {
- Value::NaturalLit(n + 1)
+ Value::ListConsClosure(t, Some(x)) => {
+ let v = th.normalize_whnf();
+ match &*v {
+ Value::EmptyListLit(_) => Value::NEListLit(vec![x]),
+ Value::NEListLit(xs) => {
+ let mut xs = xs.clone();
+ xs.insert(0, x);
+ Value::NEListLit(xs)
+ }
+ _ => {
+ drop(v);
+ fallback(Value::ListConsClosure(t, Some(x)), th)
+ }
+ }
}
- (Value::UnionConstructor(l, kts), val) => {
- Value::UnionLit(l, Thunk::from_whnf(val), kts)
+ Value::NaturalSuccClosure => {
+ let v = th.normalize_whnf();
+ match &*v {
+ Value::NaturalLit(n) => Value::NaturalLit(n + 1),
+ _ => {
+ drop(v);
+ fallback(Value::NaturalSuccClosure, th)
+ }
+ }
}
- // Can't do anything useful, convert to expr
- (f, a) => Value::Expr(rc(ExprF::App(
- f.normalize_to_expr(),
- a.normalize_to_expr(),
- ))),
+ Value::UnionConstructor(l, kts) => Value::UnionLit(l, th, kts),
+ f => fallback(f, th),
}
}
@@ -1323,8 +1339,7 @@ fn normalize_last_layer(expr: ExprF<Value, Label, X, X>) -> Value {
UnionLit(l, v, kts) => match handlers.remove(&l) {
Some(h) => {
let h = h.normalize_whnf().clone();
- let v = v.normalize_whnf().clone();
- return h.app(v);
+ return h.app_thunk(v);
}
None => UnionLit(l, v, kts),
},
diff --git a/dhall/src/typecheck.rs b/dhall/src/typecheck.rs
index 461f1cc..fb698d0 100644
--- a/dhall/src/typecheck.rs
+++ b/dhall/src/typecheck.rs
@@ -693,7 +693,7 @@ impl TypeIntermediate {
);
Typed(
Value::from_builtin(Builtin::List)
- .app(t.clone().normalize_whnf()?)
+ .app(t.normalize_whnf()?)
.into_thunk(),
Some(const_to_type(Const::Type)),
PhantomData,
@@ -709,7 +709,7 @@ impl TypeIntermediate {
);
Typed(
Value::from_builtin(Builtin::Optional)
- .app(t.clone().normalize_whnf()?)
+ .app(t.normalize_whnf()?)
.into_thunk(),
Some(const_to_type(Const::Type)),
PhantomData,