From 0507ab2f385d0fb437081b8c504547e39f160c40 Mon Sep 17 00:00:00 2001
From: Tony Garnock-Jones <tonyg@leastfixedpoint.com>
Date: Thu, 30 Sep 2021 14:46:19 +0200
Subject: [PATCH] Repair errors in preserves-schema.md

---
 preserves-schema.md | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/preserves-schema.md b/preserves-schema.md
index 8f61cfd..9194f48 100644
--- a/preserves-schema.md
+++ b/preserves-schema.md
@@ -159,7 +159,7 @@ identifierlike" literal pattern - one that matches a string, symbol,
 number or boolean:
 
     AltPattern = "@" id SimplePattern
-               / "<" id *(NamedPattern) ">"
+               / "<" id PatternSequence ">"
                / Ref
                / LiteralPattern  -- with a side condition
 
@@ -282,10 +282,20 @@ identifier.
 
 A record pattern matches an input record. It may be specified as a
 record with a literal in the label position, or as a quoted `<<rec>
-... >` record:
+... >` record with a pattern for each of the label and field-sequence
+positions:[^record-shorthand]
 
-    RecordPattern = "<<rec>" NamedPattern *(NamedPattern) ">"
-                  / "<" value *(NamedPattern) ">"
+    RecordPattern = "<<rec>" NamedPattern NamedPattern ">"
+                  / "<" value PatternSequence ">"
+
+    PatternSequence = *(NamedPattern) [NamedSimplePattern "..."]
+
+[^record-shorthand]: Note that `<label `*ps*`>` can be thought of as
+    roughly equivalent to `<<rec> <<lit> label> [`*ps*`]>`. The
+    following two definitions are equivalent:
+
+        D1 =              <foo   @a string @b string @extra any ... >.
+        D2 = <<rec> <<lit> foo> [@a string @b string @extra any ...]>.
 
 A tuple pattern matches a fixed-length sequence with specific patterns
 in each position. A variable tuple pattern is the same, but with an
@@ -293,7 +303,7 @@ additional pattern for matching additional elements following the
 fixed-position patterns.
 
     TuplePattern = "[" *(NamedPattern) "]"
-    VariableTuplePattern = "[" 1*(NamedPattern) NamedSimplePattern "..." "]"
+    VariableTuplePattern = "[" *(NamedPattern) NamedSimplePattern "..." "]"
 
 A dictionary pattern matches specific literal keys in an input
 dictionary. If no explicit name is given for a particular