From 83bc67d4572fe7961842f915d5559ee489e13dfd Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Sat, 20 Apr 2019 23:12:25 +0200
Subject: An empty optional value is purely semantic

---
 dhall_core/src/core.rs    |  4 +---
 dhall_core/src/parser.rs  |  2 +-
 dhall_core/src/printer.rs | 11 +++--------
 dhall_core/src/visitor.rs |  3 +--
 4 files changed, 6 insertions(+), 14 deletions(-)

(limited to 'dhall_core')

diff --git a/dhall_core/src/core.rs b/dhall_core/src/core.rs
index 9a8acc2..fa6fca4 100644
--- a/dhall_core/src/core.rs
+++ b/dhall_core/src/core.rs
@@ -180,10 +180,8 @@ pub enum ExprF<SubExpr, Label, Note, Embed> {
     ///  `[] : Optional a`
     ///  `[x] : Optional a`
     OldOptionalLit(Option<SubExpr>, SubExpr),
-    ///  `None t`
-    EmptyOptionalLit(SubExpr),
     ///  `Some e`
-    NEOptionalLit(SubExpr),
+    SomeLit(SubExpr),
     ///  `{ k1 : t1, k2 : t1 }`
     RecordType(BTreeMap<Label, SubExpr>),
     ///  `{ k1 = v1, k2 = v2 }`
diff --git a/dhall_core/src/parser.rs b/dhall_core/src/parser.rs
index 31249a9..ba15bae 100644
--- a/dhall_core/src/parser.rs
+++ b/dhall_core/src/parser.rs
@@ -754,7 +754,7 @@ make_parser! {
             children!(
         [expression(e)] => e,
         [Some_(()), expression(e)] => {
-            spanned(span, NEOptionalLit(rc(e)))
+            spanned(span, SomeLit(rc(e)))
         },
         [merge(()), expression(x), expression(y)] => {
             spanned(span, Merge(rc(x), rc(y), None))
diff --git a/dhall_core/src/printer.rs b/dhall_core/src/printer.rs
index ea291a9..c4bad71 100644
--- a/dhall_core/src/printer.rs
+++ b/dhall_core/src/printer.rs
@@ -38,10 +38,7 @@ impl<SE: Display + Clone, N, E: Display> Display for ExprF<SE, Label, N, E> {
             OldOptionalLit(Some(x), t) => {
                 write!(f, "[{}] : Optional {}", x, t)?;
             }
-            EmptyOptionalLit(t) => {
-                write!(f, "None {}", t)?;
-            }
-            NEOptionalLit(e) => {
+            SomeLit(e) => {
                 write!(f, "Some {}", e)?;
             }
             Merge(a, b, c) => {
@@ -159,8 +156,7 @@ impl<S: Clone, A: Display + Clone> Expr<S, A> {
             | EmptyListLit(_)
             | NEListLit(_)
             | OldOptionalLit(_, _)
-            | EmptyOptionalLit(_)
-            | NEOptionalLit(_)
+            | SomeLit(_)
             | Merge(_, _, _)
             | Annot(_, _)
                 if phase > Base =>
@@ -200,8 +196,7 @@ impl<S: Clone, A: Display + Clone> Expr<S, A> {
             ),
             EmptyListLit(t) => EmptyListLit(t.phase(Import)),
             OldOptionalLit(x, t) => OldOptionalLit(x, t.phase(Import)),
-            EmptyOptionalLit(t) => EmptyOptionalLit(t.phase(Import)),
-            NEOptionalLit(e) => NEOptionalLit(e.phase(Import)),
+            SomeLit(e) => SomeLit(e.phase(Import)),
             ExprF::App(f, a) => ExprF::App(f.phase(Import), a.phase(Import)),
             Field(a, b) => Field(a.phase(Primitive), b),
             Projection(e, ls) => Projection(e.phase(Primitive), ls),
diff --git a/dhall_core/src/visitor.rs b/dhall_core/src/visitor.rs
index c15aacd..caaefce 100644
--- a/dhall_core/src/visitor.rs
+++ b/dhall_core/src/visitor.rs
@@ -153,8 +153,7 @@ where
                 opt(x, |e| v.visit_subexpr(e))?,
                 v.visit_subexpr(t)?,
             ),
-            EmptyOptionalLit(t) => EmptyOptionalLit(v.visit_subexpr(t)?),
-            NEOptionalLit(e) => NEOptionalLit(v.visit_subexpr(e)?),
+            SomeLit(e) => SomeLit(v.visit_subexpr(e)?),
             RecordType(kts) => RecordType(btmap(kts, v)?),
             RecordLit(kvs) => RecordLit(btmap(kvs, v)?),
             UnionType(kts) => UnionType(btoptmap(kts, v)?),
-- 
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