Fix pretty print empty spans.

Author: someone-with-default-username

Nitra.Visualizer/HtmlPrettyPrintWriter.cs

@@ -35,11 +35,19 @@ protected override void Garbage(IPrettyPrintSource source, NSpan skip)
       WriteSpan(_garbageClass, text);
     }
 
-    protected override void FormatToken(IPrettyPrintSource source, NSpan token)
+    protected override void FormatToken(IPrettyPrintSource source, NSpan token, bool canBeEmpty, string ruleName)
     {
       TryPrintGarbage(source, token);
-      var text = source.Text.Substring(token.StartPos, token.Length);
-      WebUtility.HtmlEncode(text, _writer);
+      if (token.IsEmpty)
+      {
+        if (!canBeEmpty && (Options & PrettyPrintOptions.MissingNodes) == PrettyPrintOptions.MissingNodes)
+          WriteSpan(_missingNodeClass, ruleName);
+      }
+      else
+      {
+        var text = source.Text.Substring(token.StartPos, token.Length);
+        WebUtility.HtmlEncode(text, _writer);
+      }
     }
 
     protected override void FormatString(IPrettyPrintSource source, NSpan token, string text)

Nitra/Nitra.Compiler/Generation/Ast/DefineMembers-PrettyPrint.n

@@ -65,6 +65,8 @@ namespace Nitra.Compiler
                 }
                 <[ { ..$statements } ]>
 
+              | Repeat as loop when loop.IsSkipAnyPattern                => <[ writer.Token(source, $expr, true, "SkipAnyPattern"); ]>
+              | Call(SymbolRef.Some(RegularRuleSymbol as ruleSymbol), _) => <[ writer.Token(source, $expr, $(ruleSymbol.CanParseEmptyString : bool), $(ruleSymbol.Name : string)); ]>
               | Call(SymbolRef.Some(MarkerSymbol as markerSymbol), _bp) =>
                 match (markerSymbol.Node.FullNameParts)
                 {
@@ -83,8 +85,6 @@ namespace Nitra.Compiler
                   | _ => <[ writer.Whitespace(); ]>
                 }
 
-              | Repeat as loop when loop.IsSkipAnyPattern
-              | Call when rule.Type is RuleType.Chars                          => <[ writer.Token(source, $expr); ]>
               | Call(ruleRef, bp) when isRecursiveCallFromPostfixRule(ruleRef) => <[ $expr.PrettyPrint(writer, $bp); ]>
               | Call                                                           => <[ $expr.PrettyPrint(writer, 0); ]>
               | Repeat(_, _, rule) when isVoid(rule)                           => <[ writer.Whitespace(); ]>

Nitra/Nitra.Runtime/PrettyPrint/PrettyPrintWriter.n

@@ -24,7 +24,7 @@ namespace Nitra
     [RecordIgnore]
     private mutable _previousTokenPos : int;
 
-    protected abstract FormatToken(source : IPrettyPrintSource, token : NSpan) : void;
+    protected abstract FormatToken(source : IPrettyPrintSource, token : NSpan, canBeEmpty : bool, ruleName : string) : void;
     protected abstract FormatString(source : IPrettyPrintSource, token : NSpan, text : string) : void;// TODO: сделать protected
     protected abstract Garbage(source : IPrettyPrintSource, token : NSpan) : void;
     public abstract MissingNode(ruleDescriptor : RuleDescriptor) : void;
@@ -35,10 +35,10 @@ namespace Nitra
     public abstract Indent() : void;
     public abstract Unindent() : void;
 
-    public Token(source : IPrettyPrintSource, token : NSpan) : void
+    public Token(source : IPrettyPrintSource, token : NSpan, canBeEmpty : bool, ruleName : string) : void
     {
       TryPrintGarbage(source, token);
-      FormatToken(source, token);
+      FormatToken(source, token, canBeEmpty, ruleName);
     }
 
     public String(source : IPrettyPrintSource, token : NSpan, text : string) : void

Nitra/Nitra.Runtime/PrettyPrint/StringPrettyPrintWriter.n

@@ -34,11 +34,15 @@ namespace Nitra
       _ = _buffer.Append(">>");
     }
 
-    protected override FormatToken(source : IPrettyPrintSource, token : NSpan) : void
+    protected override FormatToken(source : IPrettyPrintSource, token : NSpan, canBeEmpty : bool, ruleName : string) : void
     {
       TryPrintGarbage(source, token);
 
-      _ = _buffer.Append(source.Text, token.StartPos, token.Length);
+      if (token.IsEmpty)
+        when (!canBeEmpty && Options %&& PrettyPrintOptions.MissingNodes)
+          _ = _buffer.Append('<').Append(ruleName).Append('>');
+      else
+        _ = _buffer.Append(source.Text, token.StartPos, token.Length);
     }
 
     protected override FormatString(source : IPrettyPrintSource, token : NSpan, text : string) : void