Chat session state management

LLama.Examples/ExampleRunner.cs

@@ -8,6 +8,7 @@ public class ExampleRunner
         { "Chat Session: History", ChatSessionWithHistory.Run },
         { "Chat Session: Role names", ChatSessionWithRoleName.Run },
         { "Chat Session: Role names stripped", ChatSessionStripRoleName.Run },
+        { "Chat Session: Pre-processing and reset", ChatSessionWithRestart.Run },
         { "Chat Session: Coding Assistant", CodingAssistant.Run },
         { "Chat Session: Automatic conversation", TalkToYourself.Run },
         { "Chat Session: Chinese characters", ChatChineseGB2312.Run },

LLama.Examples/Examples/ChatSessionWithHistory.cs

@@ -61,6 +61,12 @@ public static async Task Run()
                 Console.ForegroundColor = ConsoleColor.Yellow;
                 Console.WriteLine("Session saved.");
             }
+            else if (userInput == "load")
+            {
+                session.LoadSession("Assets/chat-with-bob");
+                Console.ForegroundColor = ConsoleColor.Yellow;
+                Console.WriteLine("Session loaded.");
+            }
             else if (userInput == "regenerate")
             {
                 Console.ForegroundColor = ConsoleColor.Yellow;

LLama.Examples/Examples/ChatSessionWithRestart.cs

@@ -0,0 +1,95 @@
+using LLama.Common;
+
+namespace LLama.Examples.Examples;
+
+public class ChatSessionWithRestart
+{
+    public static async Task Run()
+    {
+        string modelPath = UserSettings.GetModelPath();
+
+        var parameters = new ModelParams(modelPath)
+        {
+            ContextSize = 1024,
+            Seed = 1337,
+            GpuLayerCount = 5
+        };
+        using var model = LLamaWeights.LoadFromFile(parameters);
+        using var context = model.CreateContext(parameters);
+        var executor = new InteractiveExecutor(context);
+
+        var chatHistoryJson = File.ReadAllText("Assets/chat-with-bob.json");
+        ChatHistory chatHistory = ChatHistory.FromJson(chatHistoryJson) ?? new ChatHistory();
+        ChatSession prototypeSession = 
+            await ChatSession.InitializeSessionFromHistoryAsync(executor, chatHistory);
+        prototypeSession.WithOutputTransform(new LLamaTransforms.KeywordTextOutputStreamTransform(
+            new string[] { "User:", "Assistant:" },
+            redundancyLength: 8));
+        var resetState = prototypeSession.GetSessionState();
+
+        ChatSession session = new ChatSession(executor);
+        session.LoadSession(resetState);
+
+        InferenceParams inferenceParams = new InferenceParams()
+        {
+            Temperature = 0.9f,
+            AntiPrompts = new List<string> { "User:" }
+        };
+
+        Console.ForegroundColor = ConsoleColor.Yellow;
+        Console.WriteLine("The chat session has started. Write `save` to save session in memory."
+            + " Write `reset` to start from the last saved checkpoint");
+
+        // show the prompt
+        Console.ForegroundColor = ConsoleColor.Green;
+        string userInput = Console.ReadLine() ?? "";
+
+        while (userInput != "exit")
+        {
+            if(userInput == "reset")
+            {
+                session.LoadSession(resetState);
+                Console.WriteLine($"Reset to history:\n{session.HistoryTransform.HistoryToText(session.History)}");
+                Console.ForegroundColor = ConsoleColor.Yellow;
+                Console.WriteLine("Session reset.");
+            }
+            else if (userInput == "save")
+            {
+                resetState = session.GetSessionState();
+                Console.ForegroundColor = ConsoleColor.Yellow;
+                Console.WriteLine("Session saved.");
+            }
+            else if (userInput == "regenerate")
+            {
+                Console.ForegroundColor = ConsoleColor.Yellow;
+                Console.WriteLine("Regenerating last response ...");
+
+                await foreach (
+                    var text
+                    in session.RegenerateAssistantMessageAsync(
+                        inferenceParams))
+                {
+                    Console.ForegroundColor = ConsoleColor.White;
+                    Console.Write(text);
+                }
+            }
+            else
+            {
+                await foreach (
+                    var text
+                    in session.ChatAsync(
+                        new ChatHistory.Message(AuthorRole.User, userInput),
+                        inferenceParams))
+                {
+                    Console.ForegroundColor = ConsoleColor.White;
+                    Console.Write(text);
+                }
+            }
+
+            Console.ForegroundColor = ConsoleColor.Green;
+            userInput = Console.ReadLine() ?? "";
+
+            Console.ForegroundColor = ConsoleColor.White;
+        }
+    }
+}

LLama/Abstractions/IHistoryTransform.cs

@@ -1,10 +1,12 @@
 using LLama.Common;
+using System.Text.Json.Serialization;
 
 namespace LLama.Abstractions
 {
     /// <summary>
     /// Transform history to plain text and vice versa.
     /// </summary>
+    [JsonConverter(typeof(PolymorphicJSONConverter<IHistoryTransform>))]
     public interface IHistoryTransform
     {
         /// <summary>
@@ -21,5 +23,11 @@ public interface IHistoryTransform
         /// <param name="text">The chat history as plain text.</param>
         /// <returns>The updated history.</returns>
         ChatHistory TextToHistory(AuthorRole role, string text);
+
+        /// <summary>
+        /// Copy the transform.
+        /// </summary>
+        /// <returns></returns>
+        IHistoryTransform Clone();
     }
 }

LLama/Abstractions/ITextStreamTransform.cs

@@ -1,10 +1,13 @@
-using System.Collections.Generic;
+using LLama.Common;
+using System.Collections.Generic;
+using System.Text.Json.Serialization;
 
 namespace LLama.Abstractions
 {
     /// <summary>
     /// Takes a stream of tokens and transforms them.
     /// </summary>
+    [JsonConverter(typeof(PolymorphicJSONConverter<ITextStreamTransform>))]
     public interface ITextStreamTransform
     {
         /// <summary>
@@ -13,5 +16,11 @@ public interface ITextStreamTransform
         /// <param name="tokens"></param>
         /// <returns></returns>
         IAsyncEnumerable<string> TransformAsync(IAsyncEnumerable<string> tokens);
+
+        /// <summary>
+        /// Copy the transform.
+        /// </summary>
+        /// <returns></returns>
+        ITextStreamTransform Clone();
     }
 }

LLama/Abstractions/ITextTransform.cs

@@ -1,4 +1,7 @@
-namespace LLama.Abstractions
+using System.Text.Json.Serialization;
+using LLama.Common;
+
+namespace LLama.Abstractions
 {
     /// <summary>
     /// An interface for text transformations.
@@ -9,6 +12,7 @@
     /// - Trimming
     /// - etc.
     /// </summary>
+    [JsonConverter(typeof(PolymorphicJSONConverter<ITextTransform>))]
     public interface ITextTransform
     {
         /// <summary>
@@ -17,5 +21,11 @@ public interface ITextTransform
         /// <param name="text"></param>
         /// <returns></returns>
         string Transform(string text);
+
+        /// <summary>
+        /// Copy the transform.
+        /// </summary>
+        /// <returns></returns>
+        ITextTransform Clone();
     }
 }