Implement record puns

6 files changed, 16 insertions, 2 deletions

diff --git a/dhall/src/syntax/ast/span.rs b/dhall/src/syntax/ast/span.rs
index 50985e1..153a624 100644
--- a/dhall/src/syntax/ast/span.rs
+++ b/dhall/src/syntax/ast/span.rs
@@ -22,6 +22,7 @@ pub(crate) enum Span {
     DuplicateRecordFieldsSugar,
     DottedFieldSugar,
     WithSugar,
+    RecordPunSugar,
     /// For expressions obtained from decoding binary
     Decoded,
     /// For expressions constructed during normalization/typecheck
diff --git a/dhall/src/syntax/text/dhall.pest.visibility b/dhall/src/syntax/text/dhall.pest.visibility
index 0ff1bfe..2a89076 100644
--- a/dhall/src/syntax/text/dhall.pest.visibility
+++ b/dhall/src/syntax/text/dhall.pest.visibility
@@ -184,6 +184,8 @@ non_empty_record_type
 record_type_entry
 non_empty_record_literal
 record_literal_entry
+# record_literal_punned_entry
+# record_literal_normal_entry
 union_type
 empty_union_type
 # non_empty_union_type
diff --git a/dhall/src/syntax/text/parser.rs b/dhall/src/syntax/text/parser.rs
index f59cf06..b3c2c40 100644
--- a/dhall/src/syntax/text/parser.rs
+++ b/dhall/src/syntax/text/parser.rs
@@ -954,6 +954,11 @@ impl DhallParser {
 
     fn record_literal_entry(input: ParseInput) -> ParseResult<(Label, Expr)> {
         Ok(match_nodes!(input.into_children();
+            [label(name)] => {
+                // Desugar record pun into a variable
+                let expr = Expr::new(Var(name.clone().into()), Span::RecordPunSugar);
+                (name, expr)
+            },
             [label(name), expression(expr)] => (name, expr),
             [label(first_name), label(names).., expression(expr)] => {
                 // Desugar dotted field syntax into nested records
diff --git a/dhall/src/syntax/text/printer.rs b/dhall/src/syntax/text/printer.rs
index 5bb987b..a8991b0 100644
--- a/dhall/src/syntax/text/printer.rs
+++ b/dhall/src/syntax/text/printer.rs
@@ -357,7 +357,7 @@ impl Display for Label {
         let s = String::from(self);
         let is_reserved = match s.as_str() {
             "let" | "in" | "if" | "then" | "else" | "Type" | "Kind"
-            | "Sort" | "True" | "False" => true,
+            | "Sort" | "True" | "False" | "Some" => true,
             _ => crate::syntax::Builtin::parse(&s).is_some(),
         };
         if !is_reserved && s.chars().all(|c| c.is_ascii_alphanumeric()) {
diff --git a/dhall/tests/parser/failure/spacing/RecordTypeNoSpace.txt b/dhall/tests/parser/failure/spacing/RecordTypeNoSpace.txt
index f6427a4..b08c143 100644
--- a/dhall/tests/parser/failure/spacing/RecordTypeNoSpace.txt
+++ b/dhall/tests/parser/failure/spacing/RecordTypeNoSpace.txt
@@ -3,4 +3,4 @@
 1 | { x :T }␊
   |   ^---
   |
-  = expected non_empty_record_type_or_literal or empty_record_literal
+  = expected missing, if_, merge, NaN, Some_, toMap, assert, forall, record_type_entry, or empty_record_literal
diff --git a/dhall/tests/parser/failure/unit/RecordLitPunDotted.txt b/dhall/tests/parser/failure/unit/RecordLitPunDotted.txt
new file mode 100644
index 0000000..2e0ac22
--- /dev/null
+++ b/dhall/tests/parser/failure/unit/RecordLitPunDotted.txt
@@ -0,0 +1,6 @@
+ --> 1:7
+  |
+1 | { x.y.z }␊
+  |       ^---
+  |
+  = expected missing, if_, merge, NaN, Some_, toMap, assert, or forall