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-rw-r--r--dhall/src/semantics/nze/normalize.rs37
-rw-r--r--dhall/src/syntax/ast/expr.rs2
2 files changed, 35 insertions, 4 deletions
diff --git a/dhall/src/semantics/nze/normalize.rs b/dhall/src/semantics/nze/normalize.rs
index 604db8f..dedd659 100644
--- a/dhall/src/semantics/nze/normalize.rs
+++ b/dhall/src/semantics/nze/normalize.rs
@@ -372,11 +372,42 @@ pub(crate) fn normalize_one_layer(expr: ExprKind<Nir>, env: &NzEnv) -> NirKind {
},
_ => Ret::Expr(expr),
},
+ PartialExpr(ExprKind::Projection(v2, _)) => {
+ return normalize_one_layer(
+ ExprKind::Field(v2.clone(), l.clone()),
+ env,
+ )
+ }
_ => Ret::Expr(expr),
},
- ExprKind::ProjectionByExpr(_, _) => {
- unimplemented!("selection by expression")
- }
+
+ ExprKind::ProjectionByExpr(ref v, ref t) => match dbg!(v).kind() {
+ RecordLit(kvs) => match dbg!(t).kind() {
+ RecordType(kts) => Ret::NirKind(RecordLit(
+ kts.iter()
+ .filter_map(|(l, _)| {
+ kvs.get(l).map(|x| (l.clone(), x.clone()))
+ })
+ .collect(),
+ )),
+ _ => Ret::Expr(expr),
+ },
+ _ => match dbg!(t).kind() {
+ RecordType(kts) => {
+ use crate::syntax::map::DupTreeSet;
+ use std::iter::FromIterator;
+
+ let ts = DupTreeSet::from_iter(
+ kts.iter().map(|(l, _)| l.clone()),
+ );
+ return normalize_one_layer(
+ ExprKind::Projection(v.clone(), ts),
+ env,
+ );
+ }
+ _ => Ret::Expr(expr),
+ },
+ },
ExprKind::Merge(ref handlers, ref variant, _) => {
match handlers.kind() {
diff --git a/dhall/src/syntax/ast/expr.rs b/dhall/src/syntax/ast/expr.rs
index ce0a3d2..bb1a5b3 100644
--- a/dhall/src/syntax/ast/expr.rs
+++ b/dhall/src/syntax/ast/expr.rs
@@ -178,7 +178,7 @@ pub enum ExprKind<SubExpr> {
Field(SubExpr, Label),
/// `e.{ x, y, z }`
Projection(SubExpr, DupTreeSet<Label>),
- /// `e.(t)`
+ /// `e.(s)`
ProjectionByExpr(SubExpr, SubExpr),
/// `x::y`
Completion(SubExpr, SubExpr),