Merge pull request #220 from NexaAI/swift-group

add a send button for ios demo app; update correct chat format

examples/swift-test/Shared/ContentView.swift

@@ -3,6 +3,7 @@ import SwiftUI
 struct ContentView: View {
     @State private var viewModel = ViewModel()
     @State private var prompt = ""
+    @FocusState private var isInputActive: Bool
 
     var body: some View {
         VStack {
@@ -21,6 +22,18 @@ struct ContentView: View {
                     guard !prompt.isEmpty else { return }
                     viewModel.run(for: prompt)
                 }
+                .focused($isInputActive)
+
+            Button(action: {
+                guard !prompt.isEmpty else { return }
+                viewModel.run(for: prompt)
+                isInputActive = false
+            }) {
+                Text("Send")
+                    .frame(maxWidth: .infinity)
+            }
+            .buttonStyle(.borderedProminent)
+            .padding(.bottom)
 
             ScrollView {
                 Text(viewModel.result)

swift/Sources/NexaSwift/Models/ChatCompletionMessage.swift

@@ -220,11 +220,12 @@ class OctopusV2Formatter: ChatFormatter {
 
 //https://www.llama.com/docs/model-cards-and-prompt-formats/meta-llama-2/
 class LlamaFormatter: ChatFormatter {
-    private let systemTemplate = "[INST] <<SYS>>\n{system_message}\n<</SYS>>"
+    private let systemTemplate = "<<SYS>>\n{system_message}\n<</SYS>>\n\n"
     private let roles: [String: String] = [
-        "user": "<s>[INST]",
-        "assistant": "[/INST]"
+        "user": "<s>[INST] ",
+        "assistant": " [/INST] "
     ]
+    private let endToken = "</s>"
 
     func format(messages: [ChatCompletionRequestMessage]) -> ChatFormatterResponse {
         let formattedMessages = mapRoles(messages: messages)
@@ -233,7 +234,7 @@ class LlamaFormatter: ChatFormatter {
             systemTemplate.replacingOccurrences(of: "{system_message}", with: msg)
         }
         let prompt = formatPrompt(systemMessage: formattedSystemMessage, messages: formattedMessages)
-        return ChatFormatterResponse(prompt: prompt + "[/INST]", stop: ["</s>"])
+        return ChatFormatterResponse(prompt: prompt, stop: [endToken])
     }
 
     private func getSystemMessage(_ messages: [ChatCompletionRequestMessage]) -> String? {
@@ -268,24 +269,36 @@ class LlamaFormatter: ChatFormatter {
     }
 
     private func formatPrompt(systemMessage: String?, messages: [(String, String?)]) -> String {
-        var prompt = ""
+        var conversations: [String] = []
+        var currentConversation = ""
 
-        if let (firstRole, firstContent) = messages.first,
-           let content = firstContent {
-            if let sysMsg = systemMessage {
-                prompt += "\(firstRole) \(sysMsg)\n\(content)"
-            } else {
-                prompt += "\(firstRole) \(content)"
+        for (index, (role, content)) in messages.enumerated() {
+            if index % 2 == 0 { // User message
+                if !currentConversation.isEmpty {
+                    conversations.append(currentConversation + " " + endToken)
+                }
+                currentConversation = role // <s>[INST]
+                if index == 0 && systemMessage != nil {
+                    currentConversation += systemMessage! + content!
+                } else {
+                    currentConversation += content ?? ""
+                }
+            } else { // Assistant message
+                if let content = content {
+                    currentConversation += role + content // [/INST] response
+                }
             }
         }
 
-        for (role, content) in messages.dropFirst() {
-            if let content = content {
-                prompt += " \(role) \(content)"
-            }
+        // Add the last conversation if it's a user message without response
+        if messages.count % 2 != 0 {
+            currentConversation += roles["assistant"]!
+            conversations.append(currentConversation)
+        } else if !currentConversation.isEmpty {
+            conversations.append(currentConversation + endToken)
         }
 
-        return prompt.trimmingCharacters(in: .whitespacesAndNewlines)
+        return conversations.joined(separator: "\n")
     }
 }
 
@@ -296,8 +309,7 @@ class Llama3Formatter: ChatFormatter {
         "user": "<|start_header_id|>user<|end_header_id|>\n\n",
         "assistant": "<|start_header_id|>assistant<|end_header_id|>\n\n"
     ]
-
-    private let separator = "<|eot_id|>\n"
+    private let endToken = "<|eot_id|>"
 
     func format(messages: [ChatCompletionRequestMessage]) -> ChatFormatterResponse {
         var formattedMessages = mapRoles(messages: messages)
@@ -306,7 +318,7 @@ class Llama3Formatter: ChatFormatter {
 
         let prompt = formatPrompt(formattedMessages)
 
-        return ChatFormatterResponse(prompt: prompt, stop: [separator])
+        return ChatFormatterResponse(prompt: prompt, stop: [endToken])
     }
 
     private func mapRoles(messages: [ChatCompletionRequestMessage]) -> [(String, String?)] {
@@ -345,7 +357,7 @@ class Llama3Formatter: ChatFormatter {
         var prompt = "<|begin_of_text|>"
         for (role, content) in formattedMessages {
             if let content = content {
-                prompt += "\(role)\(content.trimmingCharacters(in: .whitespacesAndNewlines))\(separator)"
+                prompt += "\(role)\(content.trimmingCharacters(in: .whitespacesAndNewlines))\(endToken)"
             } else {
                 prompt += "\(role) "
             }
@@ -362,14 +374,15 @@ class GemmaFormatter: ChatFormatter {
         "assistant": "<start_of_turn>model\n"
     ]
 
+    private let endToken = "<end_of_turn>"
     private let separator = "<end_of_turn>\n"
 
     func format(messages: [ChatCompletionRequestMessage]) -> ChatFormatterResponse {
         var formattedMessages = mapRoles(messages: messages)
         formattedMessages.append((roles["assistant"]!, nil))
         let prompt = formatPrompt(formattedMessages)
 
-        return ChatFormatterResponse(prompt: prompt, stop: [separator])
+        return ChatFormatterResponse(prompt: prompt, stop: [endToken])
     }
 
     private func mapRoles(messages: [ChatCompletionRequestMessage]) -> [(String, String?)] {
@@ -408,6 +421,7 @@ class GemmaFormatter: ChatFormatter {
     }
 }
 
+// https://qwen.readthedocs.io/zh-cn/latest/getting_started/concepts.html#control-tokens-chat-template
 class QwenFormatter: ChatFormatter {
     private let roles: [String: String] = [
         "user": "<|im_start|>user",
@@ -464,16 +478,17 @@ class QwenFormatter: ChatFormatter {
     }
 }
 
-//https://www.promptingguide.ai/models/mistral-7b
+// https://www.promptingguide.ai/models/mistral-7b#chat-template-for-mistral-7b-instruct
 class MistralFormatter: ChatFormatter {
     private let endToken = "</s>"
+    private let conversationStart = "<s>"
     private let instructStart = "[INST] "
-    private let instructEnd = " [/INST]"
+    private let instructEnd = " [/INST] "
 
     func format(messages: [ChatCompletionRequestMessage]) -> ChatFormatterResponse {
-        var prompt = ""
+        var prompt = conversationStart  // Add <s> only once at the start
 
-        for message in messages {
+        for (index, message) in messages.enumerated() {
             switch message {
             case .user(let userMessage):
                 switch userMessage.content {
@@ -491,7 +506,12 @@ class MistralFormatter: ChatFormatter {
                 continue
             }
         }
-        prompt += instructEnd
+
+        // Add instructEnd if the last message was from user (waiting for AI response)
+        if messages.last.map({ if case .user = $0 { return true } else { return false } }) ?? false {
+            prompt += instructEnd
+        }
+
         return ChatFormatterResponse(prompt: prompt, stop: [endToken])
     }
 }