6 files changed, 197 insertions(+), 6 deletions(-)

M Core/NosSmooth.PacketSerializersGenerator/AttributeGenerators/PacketContextListAttributeGenerator.cs
M Core/NosSmooth.PacketSerializersGenerator/AttributeGenerators/PacketIndexAttributeGenerator.cs
M Core/NosSmooth.PacketSerializersGenerator/AttributeGenerators/PacketListIndexAttributeGenerator.cs
M Core/NosSmooth.PacketSerializersGenerator/ConverterDeserializationGenerator.cs
M Core/NosSmooth.Packets/Attributes/PacketIndexAttribute.cs
M Core/NosSmooth.Packets/PacketStringEnumerator.cs

@@ 33,6 33,13 @@ public class PacketContextListAttributeGenerator : IParameterGenerator
         var parameter = packetInfo.Parameters.Current;
         var attribute = parameter.Attributes.First(x => x.FullName == PacketListIndexAttributeFullName);
 
+        if (parameter.IsOptional())
+        {
+            textWriter.WriteLine($"if (obj.{parameter.GetVariableName()} is not null)");
+            textWriter.WriteLine("{");
+            textWriter.Indent++;
+        }
+
         var afterSeparator = attribute.GetNamedValue<char?>("AfterSeparator", null);
         if (afterSeparator is not null)
         {


@@ 49,6 56,13 @@ public class PacketContextListAttributeGenerator : IParameterGenerator
         generator.RemovePreparedLevel();
         generator.PopLevel();
 
+        // end optional if
+        if (parameter.IsOptional())
+        {
+            textWriter.Indent--;
+            textWriter.WriteLine("}");
+        }
+
         return null;
     }
 


@@ 59,6 73,16 @@ public class PacketContextListAttributeGenerator : IParameterGenerator
         var parameter = packetInfo.Parameters.Current;
         var attribute = parameter.Attributes.First(x => x.FullName == PacketListIndexAttributeFullName);
 
+        // add optional if
+        if (parameter.IsOptional())
+        {
+            var error = generator.StartOptionalCheck(parameter, packetInfo.Name);
+            if (error is not null)
+            {
+                return error;
+            }
+        }
+
         var afterSeparator = attribute.GetNamedValue<char?>("AfterSeparator", null);
         if (afterSeparator is not null)
         {


@@ 82,6 106,12 @@ public class PacketContextListAttributeGenerator : IParameterGenerator
 
         generator.AssignLocalVariable(parameter);
 
+        // end is last token if body
+        if (parameter.IsOptional())
+        {
+            generator.EndOptionalCheck(parameter);
+        }
+
         return null;
     }
 }=
\ No newline at end of file

@@ 31,12 31,21 @@ public class PacketIndexAttributeGenerator : IParameterGenerator
         var parameter = packetInfo.Parameters.Current;
         var attribute = parameter.Attributes.First(x => x.FullName == PacketIndexAttributeFullName);
 
+        if (parameter.IsOptional())
+        {
+            textWriter.WriteLine($"if (obj.{parameter.GetVariableName()} is not null)");
+            textWriter.WriteLine("{");
+            textWriter.Indent++;
+        }
+
+        // register after separator
         var afterSeparator = attribute.GetNamedValue<char?>("AfterSeparator", null);
         if (afterSeparator is not null)
         {
             generator.SetAfterSeparatorOnce((char)afterSeparator);
         }
 
+        // push inner separator level
         var innerSeparator = attribute.GetNamedValue<char?>("InnerSeparator", null);
         if (innerSeparator is not null)
         {


@@ 44,13 53,22 @@ public class PacketIndexAttributeGenerator : IParameterGenerator
             pushedLevel = true;
         }
 
+        // serialize, check the error.
         generator.SerializeAndCheck(parameter);
 
+        // pop inner separator level
         if (pushedLevel)
         {
             generator.PopLevel();
         }
 
+        // end optional if
+        if (parameter.IsOptional())
+        {
+            textWriter.Indent--;
+            textWriter.WriteLine("}");
+        }
+
         return null;
     }
 


@@ 62,6 80,18 @@ public class PacketIndexAttributeGenerator : IParameterGenerator
         var parameter = packetInfo.Parameters.Current;
         var attribute = parameter.Attributes.First();
 
+        generator.DeclareLocalVariable(parameter);
+
+        // add optional if
+        if (parameter.IsOptional())
+        {
+            var error = generator.StartOptionalCheck(parameter, packetInfo.Name);
+            if (error is not null)
+            {
+                return error;
+            }
+        }
+
         var afterSeparator = attribute.GetNamedValue<char?>("AfterSeparator", null);
         if (afterSeparator is not null)
         {


@@ 75,14 105,15 @@ public class PacketIndexAttributeGenerator : IParameterGenerator
             pushedLevel = true;
         }
 
-        generator.DeserializeAndCheck($"{packetInfo.Namespace}.{packetInfo.Name}", parameter, packetInfo.Parameters.IsLast);
+        generator.DeserializeAndCheck
+            ($"{packetInfo.Namespace}.{packetInfo.Name}", parameter, packetInfo.Parameters.IsLast);
 
         if (!parameter.Nullable)
         {
             generator.CheckNullError(parameter.GetResultVariableName(), parameter.Name);
         }
 
-        generator.AssignLocalVariable(parameter);
+        generator.AssignLocalVariable(parameter, false);
 
         if (pushedLevel)
         {


@@ 90,6 121,12 @@ public class PacketIndexAttributeGenerator : IParameterGenerator
             generator.PopLevel();
         }
 
+        // end is last token if body
+        if (parameter.IsOptional())
+        {
+            generator.EndOptionalCheck(parameter);
+        }
+
         return null;
     }
 }=
\ No newline at end of file

@@ 35,6 35,13 @@ public class PacketListIndexAttributeGenerator : IParameterGenerator
         var parameter = packetInfo.Parameters.Current;
         var attribute = parameter.Attributes.First(x => x.FullName == PacketListIndexAttributeFullName);
 
+        if (parameter.IsOptional())
+        {
+            textWriter.WriteLine($"if (obj.{parameter.GetVariableName()} is not null)");
+            textWriter.WriteLine("{");
+            textWriter.Indent++;
+        }
+
         var afterSeparator = attribute.GetNamedValue<char?>("AfterSeparator", null);
         if (afterSeparator is not null)
         {


@@ 51,6 58,13 @@ public class PacketListIndexAttributeGenerator : IParameterGenerator
         generator.RemovePreparedLevel();
         generator.PopLevel();
 
+        // end optional if
+        if (parameter.IsOptional())
+        {
+            textWriter.Indent--;
+            textWriter.WriteLine("}");
+        }
+
         return null;
     }
 


@@ 61,6 75,18 @@ public class PacketListIndexAttributeGenerator : IParameterGenerator
         var parameter = packetInfo.Parameters.Current;
         var attribute = parameter.Attributes.First(x => x.FullName == PacketListIndexAttributeFullName);
 
+        generator.DeclareLocalVariable(parameter);
+
+        // add optional if
+        if (parameter.IsOptional())
+        {
+            var error = generator.StartOptionalCheck(parameter, packetInfo.Name);
+            if (error is not null)
+            {
+                return error;
+            }
+        }
+
         var afterSeparator = attribute.GetNamedValue<char?>("AfterSeparator", null);
         if (afterSeparator is not null)
         {


@@ 82,7 108,13 @@ public class PacketListIndexAttributeGenerator : IParameterGenerator
             generator.CheckNullError(parameter.GetResultVariableName(), parameter.Name);
         }
 
-        generator.AssignLocalVariable(parameter);
+        generator.AssignLocalVariable(parameter, false);
+
+        // end is last token if body
+        if (parameter.IsOptional())
+        {
+            generator.EndOptionalCheck(parameter);
+        }
 
         return null;
     }

@@ 6,6 6,7 @@
 
 using System.CodeDom.Compiler;
 using NosSmooth.PacketSerializersGenerator.Data;
+using NosSmooth.PacketSerializersGenerator.Errors;
 using NosSmooth.PacketSerializersGenerator.Extensions;
 
 namespace NosSmooth.PacketSerializersGenerator;


@@ 37,6 38,14 @@ public class ConverterDeserializationGenerator
     }
 
     /// <summary>
+    /// Sets that the next token should be read to the last entry in the level.
+    /// </summary>
+    public void SetReadToLast()
+    {
+        _textWriter.WriteLine(@$"{_stringEnumeratorVariable}.SetReadToLast();");
+    }
+
+    /// <summary>
     /// Push level to the string enumerator.
     /// </summary>
     /// <param name="separator">The separator.</param>


@@ 128,8 137,64 @@ if ({resultVariableName}.Entity is null) {{
     /// Assign local variable with the result of the parameter deserialization.
     /// </summary>
     /// <param name="parameter">The parameter.</param>
-    public void AssignLocalVariable(ParameterInfo parameter)
+    public void DeclareLocalVariable(ParameterInfo parameter)
+    {
+        _textWriter.WriteLine($"{parameter.GetActualType()} {parameter.GetVariableName()};");
+    }
+
+    /// <summary>
+    /// Assign local variable with the result of the parameter deserialization.
+    /// </summary>
+    /// <param name="parameter">The parameter.</param>
+    /// <param name="declare">Whether to also declare the local variable.</param>
+    public void AssignLocalVariable(ParameterInfo parameter, bool declare = true)
+    {
+        _textWriter.WriteLine($"{(declare ? "var " : string.Empty)}{parameter.Name} = ({parameter.GetActualType()}){parameter.GetResultVariableName()}.Entity;");
+    }
+
+    /// <summary>
+    /// Begins the if for optionals, check if the parameter is not nullable.
+    /// </summary>
+    /// <param name="parameter">The parameter information.</param>
+    /// <param name="packetName">The name of the packet.</param>
+    /// <returns>An error, if any.</returns>
+    public IError? StartOptionalCheck(ParameterInfo parameter, string packetName)
     {
-        _textWriter.WriteLine($"var {parameter.Name} = ({parameter.GetActualType()}){parameter.GetResultVariableName()}.Entity;");
+        if (!parameter.Nullable)
+        {
+            return new DiagnosticError
+            (
+                "SG0006",
+                "Optional parameters must be nullable",
+                "The parameter {0} in {1} has to be nullable, because it is optional.",
+                parameter.Parameter.SyntaxTree,
+                parameter.Parameter.FullSpan,
+                new List<object?>(new[] { parameter.Name, packetName })
+            );
+        }
+
+        // serialize this parameter only if we are not on the last token.
+        _textWriter.WriteLine($"if (!(stringEnumerator.IsOnLastToken() ?? true))");
+        _textWriter.WriteLine("{");
+        _textWriter.Indent++;
+        return null;
+    }
+
+    /// <summary>
+    /// Ends the if for optionals.
+    /// </summary>
+    /// <param name="parameter">The parameter information.</param>
+    public void EndOptionalCheck(ParameterInfo parameter)
+    {
+        _textWriter.Indent--;
+        _textWriter.WriteLine("}");
+        _textWriter.WriteLine("else");
+        _textWriter.WriteLine("{");
+        _textWriter.Indent++;
+
+        _textWriter.WriteLine($"{parameter.GetVariableName()} = null;");
+
+        _textWriter.Indent--;
+        _textWriter.WriteLine("}");
     }
 }=
\ No newline at end of file

@@ 37,4 37,18 @@ public class PacketIndexAttribute : Attribute
     /// Gets the separator after this field.
     /// </summary>
     public char AfterSeparator { get; set; } = (char)0xFF;
+
+    /// <summary>
+    /// Gets or sets whether this parameter is optional.
+    /// </summary>
+    /// <remarks>
+    /// Optional attributes have to be nullable,
+    /// if the attribute is not in the string,
+    /// it will be set to null. For serializer,
+    /// if the parameter is null, it will be omitted.
+    ///
+    /// See <see cref="PacketConditionalIndexAttribute"/> for
+    /// more complex decision making about using parameters.
+    /// </remarks>
+    public bool IsOptional { get; set; } = false;
 }=
\ No newline at end of file

@@ 21,6 21,7 @@ public struct PacketStringEnumerator
     private EnumeratorLevel _currentLevel;
     private (char Separator, uint? MaxTokens)? _preparedLevel;
     private PacketToken? _currentToken;
+    private bool _readToLast;
 
     /// <summary>
     /// Initializes a new instance of the <see cref="PacketStringEnumerator"/> struct.


@@ 35,6 36,7 @@ public struct PacketStringEnumerator
         _numberOfSeparators.Add(separator, 1);
         _currentToken = null;
         _preparedLevel = null;
+        _readToLast = false;
     }
 
     /// <summary>


@@ 52,6 54,7 @@ public struct PacketStringEnumerator
         _numberOfSeparators = new Dictionary<char, ushort>(numberOfSeparators);
         _currentToken = null;
         _preparedLevel = null;
+        _readToLast = false;
     }
 
     /// <summary>


@@ 68,6 71,14 @@ public struct PacketStringEnumerator
     }
 
     /// <summary>
+    /// Sets that the next token should be read to the last entry in the level.
+    /// </summary>
+    public void SetReadToLast()
+    {
+        _readToLast = true;
+    }
+
+    /// <summary>
     /// Prepare the given level that can be set when needed.
     /// </summary>
     /// <param name="separator">The separator of the prepared level.</param>


@@ 220,7 231,8 @@ public struct PacketStringEnumerator
         bool? isLast, encounteredUpperLevel;
 
         // If the current character is a separator, stop, else, add it to the builder.
-        while (!IsSeparator(currentCharacter, out isLast, out encounteredUpperLevel))
+        // If should read to last, then read until isLast is null or true.
+        while (!IsSeparator(currentCharacter, out isLast, out encounteredUpperLevel) || (_readToLast && !(isLast ?? true)))
         {
             tokenString.Append(currentCharacter);
             currentIndex++;


@@ 235,6 247,7 @@ public struct PacketStringEnumerator
             currentCharacter = _data.Data[currentIndex];
         }
 
+        _readToLast = false;
         currentIndex++;
 
         var token = new PacketToken(tokenString.ToString(), isLast, encounteredUpperLevel, _data.ReachedEnd);