Implement parsing for record completion

2 files changed, 31 insertions, 8 deletions

diff --git a/dhall/src/syntax/text/parser.rs b/dhall/src/syntax/text/parser.rs
index 832472b..fe34aee 100644
--- a/dhall/src/syntax/text/parser.rs
+++ b/dhall/src/syntax/text/parser.rs
@@ -766,6 +766,25 @@ impl DhallParser {
     }
 
     #[alias(expression, shortcut = true)]
+    fn completion_expression(input: ParseInput) -> ParseResult<Expr> {
+        Ok(match_nodes!(input.children();
+            [expression(e)] => e,
+            [expression(first), expression(rest)..] => {
+                rest.fold(
+                    first,
+                    |acc, e| {
+                        spanned_union(
+                            acc.span(),
+                            e.span(),
+                            Completion(acc, e),
+                        )
+                    }
+                )
+            },
+        ))
+    }
+
+    #[alias(expression, shortcut = true)]
     fn selector_expression(input: ParseInput) -> ParseResult<Expr> {
         Ok(match_nodes!(input.children();
             [expression(e)] => e,
diff --git a/dhall/src/syntax/text/printer.rs b/dhall/src/syntax/text/printer.rs
index dff3479..759e7e6 100644
--- a/dhall/src/syntax/text/printer.rs
+++ b/dhall/src/syntax/text/printer.rs
@@ -64,6 +64,7 @@ impl<E: Display + Clone> UnspannedExpr<E> {
             Field(a, b) => Field(a.phase(Primitive), b),
             Projection(e, ls) => Projection(e.phase(Primitive), ls),
             ProjectionByExpr(a, b) => ProjectionByExpr(a.phase(Primitive), b),
+            Completion(a, b) => Completion(a.phase(Primitive), b.phase(Primitive)),
             e => e,
         }
     }
@@ -89,7 +90,7 @@ impl<E: Display + Clone> UnspannedExpr<E> {
             // Precedence is magically handled by the ordering of BinOps.
             ExprKind::BinOp(op, _, _) => phase > PrintPhase::BinOp(*op),
             ExprKind::App(_, _) => phase > PrintPhase::App,
-            Field(_, _) | Projection(_, _) | ProjectionByExpr(_, _) => {
+            Field(_, _) | Projection(_, _) | ProjectionByExpr(_, _) | Completion(_, _) => {
                 phase > PrintPhase::Import
             }
             _ => false,
@@ -189,13 +190,6 @@ impl<SE: Display + Clone, E: Display> Display for ExprKind<SE, E> {
             Field(a, b) => {
                 write!(f, "{}.{}", a, b)?;
             }
-            Projection(e, ls) => {
-                write!(f, "{}.", e)?;
-                fmt_list("{ ", ", ", " }", ls, f, Display::fmt)?;
-            }
-            ProjectionByExpr(a, b) => {
-                write!(f, "{}.({})", a, b)?;
-            }
             Var(a) => a.fmt(f)?,
             Const(k) => k.fmt(f)?,
             Builtin(v) => v.fmt(f)?,
@@ -224,6 +218,16 @@ impl<SE: Display + Clone, E: Display> Display for ExprKind<SE, E> {
                 }
                 Ok(())
             })?,
+            Projection(e, ls) => {
+                write!(f, "{}.", e)?;
+                fmt_list("{ ", ", ", " }", ls, f, Display::fmt)?;
+            }
+            ProjectionByExpr(a, b) => {
+                write!(f, "{}.({})", a, b)?;
+            }
+            Completion(a, b) => {
+                write!(f, "{}::{}", a, b)?;
+            }
             Import(a) => a.fmt(f)?,
             Embed(a) => a.fmt(f)?,
         }