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-rw-r--r--dhall/src/normalize.rs25
1 files changed, 13 insertions, 12 deletions
diff --git a/dhall/src/normalize.rs b/dhall/src/normalize.rs
index 461ce99..f2ad8ea 100644
--- a/dhall/src/normalize.rs
+++ b/dhall/src/normalize.rs
@@ -264,7 +264,7 @@ fn apply_builtin(b: Builtin, args: Vec<Value>) -> Value {
#[derive(Debug, Clone)]
enum EnvItem {
- Expr(Value),
+ Thunk(Thunk),
Skip(V<Label>),
}
@@ -276,7 +276,7 @@ impl EnvItem {
fn shift(&self, delta: isize, var: &V<Label>) -> Self {
use EnvItem::*;
match self {
- Expr(e) => Expr(e.shift(delta, var)),
+ Thunk(e) => Thunk(e.shift(delta, var)),
Skip(v) => Skip(v.shift(delta, var)),
}
}
@@ -286,11 +286,12 @@ impl EnvItem {
var: &V<Label>,
val: &PartiallyNormalized<'static>,
) -> Self {
- use EnvItem::*;
match self {
- Expr(e) => Expr(e.subst_shift(var, val)),
- Skip(v) if v == var => Expr(val.clone().into_whnf()),
- Skip(v) => Skip(v.shift(-1, var)),
+ EnvItem::Thunk(e) => EnvItem::Thunk(e.subst_shift(var, val)),
+ EnvItem::Skip(v) if v == var => {
+ EnvItem::Thunk(Thunk::from_whnf(val.clone().into_whnf()))
+ }
+ EnvItem::Skip(v) => EnvItem::Skip(v.shift(-1, var)),
}
}
}
@@ -302,9 +303,9 @@ impl NormalizationContext {
fn new() -> Self {
NormalizationContext(Rc::new(Context::new()))
}
- fn insert(&self, x: &Label, e: Value) -> Self {
+ fn insert(&self, x: &Label, e: Thunk) -> Self {
NormalizationContext(Rc::new(
- self.0.insert(x.clone(), EnvItem::Expr(e)),
+ self.0.insert(x.clone(), EnvItem::Thunk(e)),
))
}
fn skip(&self, x: &Label) -> Self {
@@ -317,7 +318,7 @@ impl NormalizationContext {
fn lookup(&self, var: &V<Label>) -> Value {
let V(x, n) = var;
match self.0.lookup(x, *n) {
- Some(EnvItem::Expr(e)) => e.clone(),
+ Some(EnvItem::Thunk(t)) => t.as_whnf(),
Some(EnvItem::Skip(newvar)) => Value::Var(newvar.clone()),
None => Value::Var(var.clone()),
}
@@ -329,7 +330,7 @@ impl NormalizationContext {
for v in vs.iter() {
let new_item = match v {
Type(var, _) => EnvItem::Skip(var.clone()),
- Value(e) => EnvItem::Expr(normalize_whnf(
+ Value(e) => EnvItem::Thunk(Thunk::new(
NormalizationContext::new(),
e.as_expr().embed_absurd(),
)),
@@ -1049,8 +1050,8 @@ fn normalize_whnf(ctx: NormalizationContext, expr: InputSubExpr) -> Value {
normalize_whnf(NormalizationContext::new(), e.0.embed_absurd())
}
ExprF::Let(x, _, r, b) => {
- let r = normalize_whnf(ctx.clone(), r.clone());
- normalize_whnf(ctx.insert(x, r), b.clone())
+ let t = Thunk::new(ctx.clone(), r.clone());
+ normalize_whnf(ctx.insert(x, t), b.clone())
}
ExprF::Lam(x, t, e) => Value::Lam(
x.clone(),