add a text chat example

Author: sebsto

.github/workflows/pull_request.yml

@@ -35,7 +35,7 @@ jobs:
       # We pass the list of examples here, but we can't pass an array as argument
       # Instead, we pass a String with a valid JSON array.
       # The workaround is mentioned here https://github.com/orgs/community/discussions/11692
-      examples: "[ 'converse', 'converse-stream' ]"
+      examples: "[ 'converse', 'converse-stream', 'text_chat' ]"
 
   swift-6-language-mode:
     name: Swift 6 Language Mode

Examples/text_chat/.gitignore

@@ -0,0 +1,8 @@
+.DS_Store
+/.build
+/Packages
+xcuserdata/
+DerivedData/
+.swiftpm/configuration/registries.json
+.swiftpm/xcode/package.xcworkspace/contents.xcworkspacedata
+.netrc

Examples/text_chat/Package.swift

@@ -0,0 +1,30 @@
+// swift-tools-version: 6.0
+// The swift-tools-version declares the minimum version of Swift required to build this package.
+
+import PackageDescription
+
+let package = Package(
+    name: "TextChat",
+    platforms: [.macOS(.v15), .iOS(.v18), .tvOS(.v18)],
+    products: [
+        .executable(name: "TextChat", targets: ["TextChat"]),
+    ],
+    dependencies: [
+        // for production use, uncomment the following line
+        // .package(url: "https://github.com/build-on-aws/swift-bedrock-library.git", branch: "main"),
+
+        // for local development, use the following line
+        .package(name: "swift-bedrock-library", path: "../.."),
+
+        .package(url: "https://github.com/apple/swift-log.git", from: "1.5.0"),
+    ],
+    targets: [
+        .executableTarget(
+            name: "TextChat",
+            dependencies: [
+                .product(name: "BedrockService", package: "swift-bedrock-library"),
+                .product(name: "Logging", package: "swift-log"),
+            ]
+        )
+    ]
+)

Examples/text_chat/Sources/TextChat.swift

@@ -0,0 +1,101 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift Bedrock Library open source project
+//
+// Copyright (c) 2025 Amazon.com, Inc. or its affiliates
+//                    and the Swift Bedrock Library project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of Swift Bedrock Library project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import BedrockService
+import Logging
+
+@main
+struct TextChat {
+    static func main() async throws {
+        do {
+            try await TextChat.run()
+        } catch {
+            print("Error:\n\(error)")
+        }
+    }
+    static func run() async throws {
+        var logger = Logger(label: "TextChat")
+        logger.logLevel = .debug
+
+        let bedrock = try await BedrockService(
+            region: .useast1,
+            logger: logger
+            // uncomment if you use SSO with AWS Identity Center
+            // authentication: .sso
+        )
+
+        // select a model that supports the converse modality
+        // models must be enabled in your AWS account
+        let model: BedrockModel = .claudev3_7_sonnet
+
+        guard model.hasConverseModality() else {
+            throw MyError.incorrectModality("\(model.name) does not support converse")
+        }
+
+        // a reusable var to build the requests
+        var request: ConverseRequestBuilder? = nil
+
+        // we keep track of the history of the conversation
+        var history: [Message] = []
+
+        // while the user doesn't type "exit" or "quit"
+        while true {
+
+            print("\nYou: ", terminator: "")
+            let prompt: String = readLine() ?? ""
+            guard prompt.isEmpty == false else { continue }
+            if ["exit", "quit"].contains(prompt.lowercased()) {
+                break
+            }
+
+            print("\nAssistant: ", terminator: "")
+            
+            if request == nil {
+                // create a new request
+                request = try ConverseRequestBuilder(with: model)
+                    .withPrompt(prompt)
+            } else {
+                // append the new prompt to the existing request
+                // ConverseRequestBuilder is stateles, it doesn't keep track of the history
+                request = try ConverseRequestBuilder(from: request!)
+                    .withHistory(history)
+                    .withPrompt(prompt)
+            }
+
+            // keep track of the history of the conversation
+            history.append(Message(prompt))
+
+            // send the request
+            let reply = try await bedrock.converseStream(with: request!)
+
+            for try await element in reply.stream {
+                // process the stream elements
+                switch element {
+                case .text(_, let text):
+                    print(text, terminator: "")
+                case .messageComplete(let message):
+                    print("\n")
+                    history.append(message)
+                default:
+                    break
+                }
+            }
+        }
+    }
+
+    enum MyError: Error {
+        case incorrectModality(String)
+    }
+}