From d746b3e691dc2a9853d5937d62d7ccaeb937deec Mon Sep 17 00:00:00 2001
From: Konstantin Diachenko <drakonard@gmail.com>
Date: Sun, 1 Dec 2024 13:27:14 +0530
Subject: [PATCH] Add support for empty link (with no id and values)

---
 csharp/Platform.Protocols.Lino/Link.cs    | 17 +++++++++++++----
 csharp/Platform.Protocols.Lino/Parser.peg |  6 +++---
 2 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/csharp/Platform.Protocols.Lino/Link.cs b/csharp/Platform.Protocols.Lino/Link.cs
index 4bd4025..d7ba455 100644
--- a/csharp/Platform.Protocols.Lino/Link.cs
+++ b/csharp/Platform.Protocols.Lino/Link.cs
@@ -30,14 +30,19 @@ public Link(params Link<TLinkAddress>[] values) : this(default!, values) { }
         public Link(TLinkAddress id) : this(id, default!) { }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public override string ToString() => Values.IsNullOrEmpty() ? $"({EscapeReference(Id.ToString())})" : GetLinkValuesString();
-
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        private string GetLinkValuesString() => Id == null ? $"({GetValuesString()})" : $"({EscapeReference(Id.ToString())}: {GetValuesString()})";
+        public override string ToString() => Id == null ?
+         $"({GetValuesString()})" : 
+            Values.IsNullOrEmpty() ? 
+                $"({EscapeReference(Id.ToString())})" :
+                $"({EscapeReference(Id.ToString())}: {GetValuesString()})";
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public string GetValuesString()
         {
+            if (Values.IsNullOrEmpty())
+            {
+                return "";
+            }
             var sb = new StringBuilder();
             for (int i = 0; i < Values.Count; i++)
             {
@@ -80,6 +85,10 @@ public Link<TLinkAddress> Simplify()
 
         public static string EscapeReference(string reference)
         {
+            if (string.IsNullOrWhiteSpace(reference))
+            {
+                return "";
+            }
             if  (
                     reference.Contains(":") ||
                     reference.Contains("(") ||
diff --git a/csharp/Platform.Protocols.Lino/Parser.peg b/csharp/Platform.Protocols.Lino/Parser.peg
index 814f298..3ca28f7 100644
--- a/csharp/Platform.Protocols.Lino/Parser.peg
+++ b/csharp/Platform.Protocols.Lino/Parser.peg
@@ -11,13 +11,13 @@ anyLink <Link<string>> = ml:multiLineAnyLink eol { ml } / sl:singleLineAnyLink {
 multiLineAnyLink <Link<string>> = multiLinePointLink / multiLineValueLink / multiLineLink
 singleLineAnyLink <Link<string>> = fl:singleLineLink eol { fl } / pl:singleLinePointLink eol { pl } / vl:singleLineValueLink eol { vl }
 multiLineValueAndWhitespace <Link<string>> = value:referenceOrLink _ { value }
-multiLineValues <IList<Link<string>>> = _ list:multiLineValueAndWhitespace+ { list }
+multiLineValues <IList<Link<string>>> = _ list:multiLineValueAndWhitespace* { list }
 singleLineValueAndWhitespace <Link<string>> = __ value:referenceOrLink { value }
 singleLineValues <IList<Link<string>>> = list:singleLineValueAndWhitespace+ { list }
 singleLineLink <Link<string>> = __ id:(reference) __ ":" v:singleLineValues { new Link<string>(id, v) }
-multiLineLink <Link<string>> = "(" _ id:(reference) _ ":" v:multiLineValues ")" { new Link<string>(id, v) }
+multiLineLink <Link<string>> = "(" _ id:(reference) _ ":" v:multiLineValues _ ")" { new Link<string>(id, v) }
 singleLineValueLink <Link<string>> = v:singleLineValues { new Link<string>(v) }
-multiLineValueLink <Link<string>> = "(" v:multiLineValues ")" { new Link<string>(v) }
+multiLineValueLink <Link<string>> = "(" v:multiLineValues _ ")" { new Link<string>(v) }
 pointLink <Link<string>> = id:(reference) { new Link<string>(id) }
 singleLinePointLink<Link<string>> = __ l:pointLink { l }
 multiLinePointLink<Link<string>> = "(" _ l:pointLink _ ")" { l }