From 2f50a298c0c7b9904344a9231e0276c84c40a060 Mon Sep 17 00:00:00 2001
From: Morgan Chen <morganchen12@gmail.com>
Date: Tue, 9 Jan 2024 14:53:01 -0800
Subject: [PATCH 01/15] almost nonbreaking change

---
 .../ViewModels/PhotoReasoningViewModel.swift  |  2 +-
 Sources/GoogleAI/Chat.swift                   |  4 +-
 Sources/GoogleAI/GenerativeModel.swift        |  6 +-
 Sources/GoogleAI/ModelContent.swift           |  2 +-
 Sources/GoogleAI/PartsRepresentable.swift     | 87 ++++++++++++-------
 5 files changed, 65 insertions(+), 36 deletions(-)

diff --git a/Examples/GenerativeAISample/GenerativeAIMultimodalSample/ViewModels/PhotoReasoningViewModel.swift b/Examples/GenerativeAISample/GenerativeAIMultimodalSample/ViewModels/PhotoReasoningViewModel.swift
index e4613d2..0822175 100644
--- a/Examples/GenerativeAISample/GenerativeAIMultimodalSample/ViewModels/PhotoReasoningViewModel.swift
+++ b/Examples/GenerativeAISample/GenerativeAIMultimodalSample/ViewModels/PhotoReasoningViewModel.swift
@@ -58,7 +58,7 @@ class PhotoReasoningViewModel: ObservableObject {
 
       let prompt = "Look at the image(s), and then answer the following question: \(userInput)"
 
-      var images = [PartsRepresentable]()
+      var images = [any PartsRepresentable]()
       for item in selectedItems {
         if let data = try? await item.loadTransferable(type: Data.self) {
           images.append(ModelContent.Part.png(data))
diff --git a/Sources/GoogleAI/Chat.swift b/Sources/GoogleAI/Chat.swift
index 968cd0b..55dcdf6 100644
--- a/Sources/GoogleAI/Chat.swift
+++ b/Sources/GoogleAI/Chat.swift
@@ -30,7 +30,7 @@ public class Chat {
   public var history: [ModelContent]
 
   /// See ``sendMessage(_:)-3ify5``.
-  public func sendMessage(_ parts: PartsRepresentable...) async throws -> GenerateContentResponse {
+  public func sendMessage(_ parts: any PartsRepresentable...) async throws -> GenerateContentResponse {
     return try await sendMessage([ModelContent(parts: parts)])
   }
 
@@ -66,7 +66,7 @@ public class Chat {
 
   /// See ``sendMessageStream(_:)-4abs3``.
   @available(macOS 12.0, *)
-  public func sendMessageStream(_ parts: PartsRepresentable...)
+  public func sendMessageStream(_ parts: any PartsRepresentable...)
     -> AsyncThrowingStream<GenerateContentResponse, Error> {
     return sendMessageStream([ModelContent(parts: parts)])
   }
diff --git a/Sources/GoogleAI/GenerativeModel.swift b/Sources/GoogleAI/GenerativeModel.swift
index 49b5796..ea97053 100644
--- a/Sources/GoogleAI/GenerativeModel.swift
+++ b/Sources/GoogleAI/GenerativeModel.swift
@@ -88,7 +88,7 @@ public final class GenerativeModel {
   /// for conforming types).
   /// - Returns: The content generated by the model.
   /// - Throws: A ``GenerateContentError`` if the request failed.
-  public func generateContent(_ parts: PartsRepresentable...)
+  public func generateContent(_ parts: any PartsRepresentable...)
     async throws -> GenerateContentResponse {
     return try await generateContent([ModelContent(parts: parts)])
   }
@@ -139,7 +139,7 @@ public final class GenerativeModel {
   /// - Returns: A stream wrapping content generated by the model or a ``GenerateContentError``
   ///     error if an error occurred.
   @available(macOS 12.0, *)
-  public func generateContentStream(_ parts: PartsRepresentable...)
+  public func generateContentStream(_ parts: any PartsRepresentable...)
     -> AsyncThrowingStream<GenerateContentResponse, Error> {
     return generateContentStream([ModelContent(parts: parts)])
   }
@@ -208,7 +208,7 @@ public final class GenerativeModel {
   /// - Returns: The results of running the model's tokenizer on the input; contains
   /// ``CountTokensResponse/totalTokens``.
   /// - Throws: A ``CountTokensError`` if the tokenization request failed.
-  public func countTokens(_ parts: PartsRepresentable...) async throws -> CountTokensResponse {
+  public func countTokens(_ parts: any PartsRepresentable...) async throws -> CountTokensResponse {
     return try await countTokens([ModelContent(parts: parts)])
   }
 
diff --git a/Sources/GoogleAI/ModelContent.swift b/Sources/GoogleAI/ModelContent.swift
index 898d10f..981c615 100644
--- a/Sources/GoogleAI/ModelContent.swift
+++ b/Sources/GoogleAI/ModelContent.swift
@@ -117,7 +117,7 @@ public struct ModelContent: Codable, Equatable {
 
   /// Creates a new value from any data interpretable as a ``Part``. See ``PartsRepresentable``
   /// for types that can be interpreted as `Part`s.
-  public init(role: String? = "user", _ parts: PartsRepresentable...) {
+  public init(role: String? = "user", _ parts: any PartsRepresentable...) {
     self.init(role: role, parts: parts)
   }
 }
diff --git a/Sources/GoogleAI/PartsRepresentable.swift b/Sources/GoogleAI/PartsRepresentable.swift
index 50b0979..d2d92b9 100644
--- a/Sources/GoogleAI/PartsRepresentable.swift
+++ b/Sources/GoogleAI/PartsRepresentable.swift
@@ -22,88 +22,118 @@ import UniformTypeIdentifiers
 
 private let imageCompressionQuality: CGFloat = 0.8
 
-/// A protocol describing any data that could be interpreted as model input data.
+/// A protocol describing any data that could be serialized to model-interpretable input data,
+/// where the serialization process might fail with an error.
 public protocol PartsRepresentable {
-  var partsValue: [ModelContent.Part] { get }
+  associatedtype ErrorType where ErrorType: Error
+  func toModelContentParts() -> Result<[ModelContent.Part], ErrorType>
+}
+
+public extension PartsRepresentable {
+  var partsValue: [ModelContent.Part] {
+    let content = toModelContentParts()
+    switch content {
+    case .success(let success):
+      return success
+    case .failure(let failure):
+      Logging.default
+          .error("Error converting \(type(of: self)) value to model content parts: \(failure)")
+      return []
+    }
+  }
 }
 
 /// Enables a `String` to be passed in as ``PartsRepresentable``.
 extension String: PartsRepresentable {
-  public var partsValue: [ModelContent.Part] {
-    return [.text(self)]
+  public typealias ErrorType = Never
+
+  public func toModelContentParts() -> Result<[ModelContent.Part], Never> {
+    return .success([.text(self)])
   }
 }
 
 /// Enables a ``ModelContent.Part`` to be passed in as ``PartsRepresentable``.
 extension ModelContent.Part: PartsRepresentable {
-  public var partsValue: [ModelContent.Part] {
-    return [self]
+  public typealias ErrorType = Never
+  public func toModelContentParts() -> Result<[ModelContent.Part], Never> {
+    return .success([self])
   }
 }
 
 /// Enable an `Array` of ``PartsRepresentable`` values to be passed in as a single
 /// ``PartsRepresentable``.
 extension [any PartsRepresentable]: PartsRepresentable {
-  public var partsValue: [ModelContent.Part] {
-    return flatMap { $0.partsValue }
+  public typealias ErrorType = Never
+  public func toModelContentParts() -> Result<[ModelContent.Part], Never> {
+    return .success(flatMap { $0.partsValue })
   }
 }
 
+/// An enum describing failures that can occur when converting image types to model content data.
+/// For some image types like `CIImage`, creating valid model content requires creating a JPEG
+/// representation of the image that may not yet exist, which may be computationally expensive.
+public enum ImageConversionError: Error {
+
+  /// The underlying image was invalid. The error will be accompanied by the actual image object.
+  case invalidUnderlyingImage(Any)
+
+  /// A valid image destination could not be constructed.
+  case couldNotAllocateDestination
+
+  /// JPEG image data conversion failed, accompanied by the original image.
+  case couldNotConvertToJPEG(Any)
+}
+
 #if canImport(UIKit)
   /// Enables images to be representable as ``PartsRepresentable``.
   extension UIImage: PartsRepresentable {
-    public var partsValue: [ModelContent.Part] {
+
+    public func toModelContentParts() -> Result<[ModelContent.Part], ImageConversionError> {
       guard let data = jpegData(compressionQuality: imageCompressionQuality) else {
-        Logging.default.error("[GoogleGenerativeAI] Couldn't create JPEG from UIImage.")
-        return []
+        return .failure(.couldNotConvertToJPEG(self))
       }
-
-      return [ModelContent.Part.data(mimetype: "image/jpeg", data)]
+      return .success([ModelContent.Part.data(mimetype: "image/jpeg", data)])
     }
   }
 
 #elseif canImport(AppKit)
   /// Enables images to be representable as ``PartsRepresentable``.
   extension NSImage: PartsRepresentable {
-    public var partsValue: [ModelContent.Part] {
+    public func toModelContentParts() -> Result<[ModelContent.Part], ImageConversionError> {
       guard let cgImage = cgImage(forProposedRect: nil, context: nil, hints: nil) else {
-        Logging.default.error("[GoogleGenerativeAI] Couldn't create CGImage from NSImage.")
-        return []
+        return .failure(.invalidUnderlyingImage(self))
       }
       let bmp = NSBitmapImageRep(cgImage: cgImage)
       guard let data = bmp.representation(using: .jpeg, properties: [.compressionFactor: 0.8])
       else {
-        Logging.default.error("[GoogleGenerativeAI] Couldn't create BMP from CGImage.")
-        return []
+        return .failure(.couldNotConvertToJPEG(bmp))
       }
-      return [ModelContent.Part.data(mimetype: "image/jpeg", data)]
+      return .success([ModelContent.Part.data(mimetype: "image/jpeg", data)])
     }
   }
 #endif
 
 extension CGImage: PartsRepresentable {
-  public var partsValue: [ModelContent.Part] {
+  public func toModelContentParts() -> Result<[ModelContent.Part], ImageConversionError> {
     let output = NSMutableData()
     guard let imageDestination = CGImageDestinationCreateWithData(
       output, UTType.jpeg.identifier as CFString, 1, nil
     ) else {
-      Logging.default.error("[GoogleGenerativeAI] Couldn't create JPEG from CGImage.")
-      return []
+      return .failure(.couldNotAllocateDestination)
     }
     CGImageDestinationAddImage(imageDestination, self, nil)
     CGImageDestinationSetProperties(imageDestination, [
       kCGImageDestinationLossyCompressionQuality: imageCompressionQuality,
     ] as CFDictionary)
     if CGImageDestinationFinalize(imageDestination) {
-      return [.data(mimetype: "image/jpeg", output as Data)]
+      return .success([.data(mimetype: "image/jpeg", output as Data)])
     }
-    Logging.default.error("[GoogleGenerativeAI] Couldn't create JPEG from CGImage.")
-    return []
+    return .failure(.couldNotConvertToJPEG(self))
   }
 }
 
 extension CIImage: PartsRepresentable {
-  public var partsValue: [ModelContent.Part] {
+  public func toModelContentParts() -> Result<[ModelContent.Part], ImageConversionError> {
     let context = CIContext()
     let jpegData = (colorSpace ?? CGColorSpace(name: CGColorSpace.sRGB))
       .flatMap {
@@ -113,9 +143,8 @@ extension CIImage: PartsRepresentable {
         context.jpegRepresentation(of: self, colorSpace: $0, options: [:])
       }
     if let jpegData = jpegData {
-      return [.data(mimetype: "image/jpeg", jpegData)]
+      return .success([.data(mimetype: "image/jpeg", jpegData)])
     }
-    Logging.default.error("[GoogleGenerativeAI] Couldn't create JPEG from CIImage.")
-    return []
+    return .failure(.couldNotConvertToJPEG(self))
   }
 }

From 1585a969dee2d86d0395e63eb31d3c25a3567e66 Mon Sep 17 00:00:00 2001
From: Morgan Chen <morganchen12@gmail.com>
Date: Wed, 10 Jan 2024 14:24:36 -0800
Subject: [PATCH 02/15] style

---
 Sources/GoogleAI/Chat.swift               | 3 ++-
 Sources/GoogleAI/PartsRepresentable.swift | 8 +++-----
 2 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/Sources/GoogleAI/Chat.swift b/Sources/GoogleAI/Chat.swift
index 55dcdf6..51c0fc4 100644
--- a/Sources/GoogleAI/Chat.swift
+++ b/Sources/GoogleAI/Chat.swift
@@ -30,7 +30,8 @@ public class Chat {
   public var history: [ModelContent]
 
   /// See ``sendMessage(_:)-3ify5``.
-  public func sendMessage(_ parts: any PartsRepresentable...) async throws -> GenerateContentResponse {
+  public func sendMessage(_ parts: any PartsRepresentable...) async throws
+    -> GenerateContentResponse {
     return try await sendMessage([ModelContent(parts: parts)])
   }
 
diff --git a/Sources/GoogleAI/PartsRepresentable.swift b/Sources/GoogleAI/PartsRepresentable.swift
index d2d92b9..20b7641 100644
--- a/Sources/GoogleAI/PartsRepresentable.swift
+++ b/Sources/GoogleAI/PartsRepresentable.swift
@@ -33,11 +33,11 @@ public extension PartsRepresentable {
   var partsValue: [ModelContent.Part] {
     let content = toModelContentParts()
     switch content {
-    case .success(let success):
+    case let .success(success):
       return success
-    case .failure(let failure):
+    case let .failure(failure):
       Logging.default
-          .error("Error converting \(type(of: self)) value to model content parts: \(failure)")
+        .error("Error converting \(type(of: self)) value to model content parts: \(failure)")
       return []
     }
   }
@@ -73,7 +73,6 @@ extension [any PartsRepresentable]: PartsRepresentable {
 /// For some image types like `CIImage`, creating valid model content requires creating a JPEG
 /// representation of the image that may not yet exist, which may be computationally expensive.
 public enum ImageConversionError: Error {
-
   /// The underlying image was invalid. The error will be accompanied by the actual image object.
   case invalidUnderlyingImage(Any)
 
@@ -87,7 +86,6 @@ public enum ImageConversionError: Error {
 #if canImport(UIKit)
   /// Enables images to be representable as ``PartsRepresentable``.
   extension UIImage: PartsRepresentable {
-
     public func toModelContentParts() -> Result<[ModelContent.Part], ImageConversionError> {
       guard let data = jpegData(compressionQuality: imageCompressionQuality) else {
         return .failure(.couldNotConvertToJPEG(self))

From b47d4dd14a7b4d929b9cf577e6ed005b2d0e1a85 Mon Sep 17 00:00:00 2001
From: Morgan Chen <morganchen12@gmail.com>
Date: Fri, 19 Jan 2024 14:12:57 -0800
Subject: [PATCH 03/15] make partsvalue accessible only when error is never

---
 Sources/GoogleAI/ModelContent.swift           |   7 +-
 .../GoogleAI/PartsRepresentable+Image.swift   | 101 +++++++++++++++
 Sources/GoogleAI/PartsRepresentable.swift     | 118 ++++--------------
 3 files changed, 129 insertions(+), 97 deletions(-)
 create mode 100644 Sources/GoogleAI/PartsRepresentable+Image.swift

diff --git a/Sources/GoogleAI/ModelContent.swift b/Sources/GoogleAI/ModelContent.swift
index 981c615..df99efa 100644
--- a/Sources/GoogleAI/ModelContent.swift
+++ b/Sources/GoogleAI/ModelContent.swift
@@ -106,7 +106,12 @@ public struct ModelContent: Codable, Equatable {
   /// ``Part``. See ``PartsRepresentable`` for types that can be interpreted as `Part`s.
   public init(role: String? = "user", parts: some PartsRepresentable) {
     self.role = role
-    self.parts = parts.partsValue
+    do {
+      try self.parts = parts.tryPartsValue()
+    } catch {
+      Logging.default.error("Error creating parts: \(error)")
+      self.parts = []
+    }
   }
 
   /// Creates a new value from a list of ``Part``s.
diff --git a/Sources/GoogleAI/PartsRepresentable+Image.swift b/Sources/GoogleAI/PartsRepresentable+Image.swift
new file mode 100644
index 0000000..de12291
--- /dev/null
+++ b/Sources/GoogleAI/PartsRepresentable+Image.swift
@@ -0,0 +1,101 @@
+// Copyright 2024 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import UniformTypeIdentifiers
+#if canImport(UIKit)
+  import UIKit // For UIImage extensions.
+#elseif canImport(AppKit)
+  import AppKit // For NSImage extensions.
+#endif
+
+private let imageCompressionQuality: CGFloat = 0.8
+
+/// An enum describing failures that can occur when converting image types to model content data.
+/// For some image types like `CIImage`, creating valid model content requires creating a JPEG
+/// representation of the image that may not yet exist, which may be computationally expensive.
+public enum ImageConversionError: Error {
+  /// The underlying image was invalid. The error will be accompanied by the actual image object.
+  case invalidUnderlyingImage(CGImage)
+
+  /// A valid image destination could not be allocated.
+  case couldNotAllocateDestination
+
+  /// JPEG image data conversion failed, accompanied by the original image, which may be an
+  /// instance of `NSImageRep`, `UIImage`, `CGImage`, or `CIImage`.
+  case couldNotConvertToJPEG(Any)
+}
+
+#if canImport(UIKit)
+  /// Enables images to be representable as ``PartsRepresentable``.
+  extension UIImage: PartsRepresentable {
+    public func toModelContentParts() -> Result<[ModelContent.Part], ImageConversionError> {
+      guard let data = jpegData(compressionQuality: imageCompressionQuality) else {
+        return .failure(.couldNotConvertToJPEG(self))
+      }
+      return .success([ModelContent.Part.data(mimetype: "image/jpeg", data)])
+    }
+  }
+
+#elseif canImport(AppKit)
+  /// Enables images to be representable as ``PartsRepresentable``.
+  extension NSImage: PartsRepresentable {
+    public func toModelContentParts() -> Result<[ModelContent.Part], ImageConversionError> {
+      guard let cgImage = cgImage(forProposedRect: nil, context: nil, hints: nil) else {
+        return .failure(.invalidUnderlyingImage(self))
+      }
+      let bmp = NSBitmapImageRep(cgImage: cgImage)
+      guard let data = bmp.representation(using: .jpeg, properties: [.compressionFactor: 0.8])
+      else {
+        return .failure(.couldNotConvertToJPEG(bmp))
+      }
+      return .success([ModelContent.Part.data(mimetype: "image/jpeg", data)])
+    }
+  }
+#endif
+
+extension CGImage: PartsRepresentable {
+  public func toModelContentParts() -> Result<[ModelContent.Part], ImageConversionError> {
+    let output = NSMutableData()
+    guard let imageDestination = CGImageDestinationCreateWithData(
+      output, UTType.jpeg.identifier as CFString, 1, nil
+    ) else {
+      return .failure(.couldNotAllocateDestination)
+    }
+    CGImageDestinationAddImage(imageDestination, self, nil)
+    CGImageDestinationSetProperties(imageDestination, [
+      kCGImageDestinationLossyCompressionQuality: imageCompressionQuality,
+    ] as CFDictionary)
+    if CGImageDestinationFinalize(imageDestination) {
+      return .success([.data(mimetype: "image/jpeg", output as Data)])
+    }
+    return .failure(.couldNotConvertToJPEG(self))
+  }
+}
+
+extension CIImage: PartsRepresentable {
+  public func toModelContentParts() -> Result<[ModelContent.Part], ImageConversionError> {
+    let context = CIContext()
+    let jpegData = (colorSpace ?? CGColorSpace(name: CGColorSpace.sRGB))
+      .flatMap {
+        // The docs specify kCGImageDestinationLossyCompressionQuality as a supported option, but
+        // Swift's type system does not allow this.
+        // [kCGImageDestinationLossyCompressionQuality: imageCompressionQuality]
+        context.jpegRepresentation(of: self, colorSpace: $0, options: [:])
+      }
+    if let jpegData = jpegData {
+      return .success([.data(mimetype: "image/jpeg", jpegData)])
+    }
+    return .failure(.couldNotConvertToJPEG(self))
+  }
+}
diff --git a/Sources/GoogleAI/PartsRepresentable.swift b/Sources/GoogleAI/PartsRepresentable.swift
index 20b7641..dde96cf 100644
--- a/Sources/GoogleAI/PartsRepresentable.swift
+++ b/Sources/GoogleAI/PartsRepresentable.swift
@@ -13,14 +13,6 @@
 // limitations under the License.
 
 import Foundation
-import UniformTypeIdentifiers
-#if canImport(UIKit)
-  import UIKit // For UIImage extensions.
-#elseif canImport(AppKit)
-  import AppKit // For NSImage extensions.
-#endif
-
-private let imageCompressionQuality: CGFloat = 0.8
 
 /// A protocol describing any data that could be serialized to model-interpretable input data,
 /// where the serialization process might fail with an error.
@@ -30,28 +22,24 @@ public protocol PartsRepresentable {
 }
 
 public extension PartsRepresentable {
+
+  func tryPartsValue() throws -> [ModelContent.Part] {
+    return try toModelContentParts().get()
+  }
+
+}
+
+public extension PartsRepresentable where ErrorType == Never {
+
   var partsValue: [ModelContent.Part] {
     let content = toModelContentParts()
     switch content {
     case let .success(success):
       return success
-    case let .failure(failure):
-      Logging.default
-        .error("Error converting \(type(of: self)) value to model content parts: \(failure)")
-      return []
     }
   }
 }
 
-/// Enables a `String` to be passed in as ``PartsRepresentable``.
-extension String: PartsRepresentable {
-  public typealias ErrorType = Never
-
-  public func toModelContentParts() -> Result<[ModelContent.Part], Never> {
-    return .success([.text(self)])
-  }
-}
-
 /// Enables a ``ModelContent.Part`` to be passed in as ``PartsRepresentable``.
 extension ModelContent.Part: PartsRepresentable {
   public typealias ErrorType = Never
@@ -63,86 +51,24 @@ extension ModelContent.Part: PartsRepresentable {
 /// Enable an `Array` of ``PartsRepresentable`` values to be passed in as a single
 /// ``PartsRepresentable``.
 extension [any PartsRepresentable]: PartsRepresentable {
-  public typealias ErrorType = Never
-  public func toModelContentParts() -> Result<[ModelContent.Part], Never> {
-    return .success(flatMap { $0.partsValue })
-  }
-}
-
-/// An enum describing failures that can occur when converting image types to model content data.
-/// For some image types like `CIImage`, creating valid model content requires creating a JPEG
-/// representation of the image that may not yet exist, which may be computationally expensive.
-public enum ImageConversionError: Error {
-  /// The underlying image was invalid. The error will be accompanied by the actual image object.
-  case invalidUnderlyingImage(Any)
+  public typealias ErrorType = Error
 
-  /// A valid image destination could not be constructed.
-  case couldNotAllocateDestination
-
-  /// JPEG image data conversion failed, accompanied by the original image.
-  case couldNotConvertToJPEG(Any)
-}
-
-#if canImport(UIKit)
-  /// Enables images to be representable as ``PartsRepresentable``.
-  extension UIImage: PartsRepresentable {
-    public func toModelContentParts() -> Result<[ModelContent.Part], ImageConversionError> {
-      guard let data = jpegData(compressionQuality: imageCompressionQuality) else {
-        return .failure(.couldNotConvertToJPEG(self))
-      }
-      return .success([ModelContent.Part.data(mimetype: "image/jpeg", data)])
-    }
-  }
-
-#elseif canImport(AppKit)
-  /// Enables images to be representable as ``PartsRepresentable``.
-  extension NSImage: PartsRepresentable {
-    public func toModelContentParts() -> Result<[ModelContent.Part], ImageConversionError> {
-      guard let cgImage = cgImage(forProposedRect: nil, context: nil, hints: nil) else {
-        return .failure(.invalidUnderlyingImage(self))
-      }
-      let bmp = NSBitmapImageRep(cgImage: cgImage)
-      guard let data = bmp.representation(using: .jpeg, properties: [.compressionFactor: 0.8])
-      else {
-        return .failure(.couldNotConvertToJPEG(bmp))
+  public func toModelContentParts() -> Result<[ModelContent.Part], Error> {
+    let result = { () throws -> [ModelContent.Part] in
+      try compactMap { element in
+        return try element.tryPartsValue()
       }
-      return .success([ModelContent.Part.data(mimetype: "image/jpeg", data)])
-    }
-  }
-#endif
-
-extension CGImage: PartsRepresentable {
-  public func toModelContentParts() -> Result<[ModelContent.Part], ImageConversionError> {
-    let output = NSMutableData()
-    guard let imageDestination = CGImageDestinationCreateWithData(
-      output, UTType.jpeg.identifier as CFString, 1, nil
-    ) else {
-      return .failure(.couldNotAllocateDestination)
-    }
-    CGImageDestinationAddImage(imageDestination, self, nil)
-    CGImageDestinationSetProperties(imageDestination, [
-      kCGImageDestinationLossyCompressionQuality: imageCompressionQuality,
-    ] as CFDictionary)
-    if CGImageDestinationFinalize(imageDestination) {
-      return .success([.data(mimetype: "image/jpeg", output as Data)])
+      .flatMap({ $0 })
     }
-    return .failure(.couldNotConvertToJPEG(self))
+    return Result(catching: result)
   }
 }
 
-extension CIImage: PartsRepresentable {
-  public func toModelContentParts() -> Result<[ModelContent.Part], ImageConversionError> {
-    let context = CIContext()
-    let jpegData = (colorSpace ?? CGColorSpace(name: CGColorSpace.sRGB))
-      .flatMap {
-        // The docs specify kCGImageDestinationLossyCompressionQuality as a supported option, but
-        // Swift's type system does not allow this.
-        // [kCGImageDestinationLossyCompressionQuality: imageCompressionQuality]
-        context.jpegRepresentation(of: self, colorSpace: $0, options: [:])
-      }
-    if let jpegData = jpegData {
-      return .success([.data(mimetype: "image/jpeg", jpegData)])
-    }
-    return .failure(.couldNotConvertToJPEG(self))
+/// Enables a `String` to be passed in as ``PartsRepresentable``.
+extension String: PartsRepresentable {
+  public typealias ErrorType = Never
+
+  public func toModelContentParts() -> Result<[ModelContent.Part], Never> {
+    return .success([.text(self)])
   }
 }

From ed2b972cf35f4a1b236e1999227dd713a1814e2c Mon Sep 17 00:00:00 2001
From: Morgan Chen <morganchen12@gmail.com>
Date: Fri, 19 Jan 2024 14:19:06 -0800
Subject: [PATCH 04/15] fix tests

---
 Sources/GoogleAI/PartsRepresentable.swift         | 7 ++-----
 Tests/GoogleAITests/PartsRepresentableTests.swift | 8 ++++----
 2 files changed, 6 insertions(+), 9 deletions(-)

diff --git a/Sources/GoogleAI/PartsRepresentable.swift b/Sources/GoogleAI/PartsRepresentable.swift
index dde96cf..deaf5a9 100644
--- a/Sources/GoogleAI/PartsRepresentable.swift
+++ b/Sources/GoogleAI/PartsRepresentable.swift
@@ -22,15 +22,12 @@ public protocol PartsRepresentable {
 }
 
 public extension PartsRepresentable {
-
   func tryPartsValue() throws -> [ModelContent.Part] {
     return try toModelContentParts().get()
   }
-
 }
 
 public extension PartsRepresentable where ErrorType == Never {
-
   var partsValue: [ModelContent.Part] {
     let content = toModelContentParts()
     switch content {
@@ -56,9 +53,9 @@ extension [any PartsRepresentable]: PartsRepresentable {
   public func toModelContentParts() -> Result<[ModelContent.Part], Error> {
     let result = { () throws -> [ModelContent.Part] in
       try compactMap { element in
-        return try element.tryPartsValue()
+        try element.tryPartsValue()
       }
-      .flatMap({ $0 })
+      .flatMap { $0 }
     }
     return Result(catching: result)
   }
diff --git a/Tests/GoogleAITests/PartsRepresentableTests.swift b/Tests/GoogleAITests/PartsRepresentableTests.swift
index d513f08..5feb3f5 100644
--- a/Tests/GoogleAITests/PartsRepresentableTests.swift
+++ b/Tests/GoogleAITests/PartsRepresentableTests.swift
@@ -38,14 +38,14 @@ final class PartsRepresentableTests: XCTestCase {
       )!
       return ctx.makeImage()!
     }
-    let modelContent = image.partsValue
+    let modelContent = try image.tryPartsValue()
     XCTAssert(modelContent.count > 0, "Expected non-empty model content for CGImage: \(image)")
   }
 
   func testModelContentFromCIImageIsNotEmpty() throws {
     let image = CIImage(color: CIColor.red)
       .cropped(to: CGRect(origin: CGPointZero, size: CGSize(width: 16, height: 16)))
-    let modelContent = image.partsValue
+    let modelContent = try image.tryPartsValue()
     XCTAssert(modelContent.count > 0, "Expected non-empty model content for CGImage: \(image)")
   }
 
@@ -54,7 +54,7 @@ final class PartsRepresentableTests: XCTestCase {
       let coreImage = CIImage(color: CIColor.red)
         .cropped(to: CGRect(origin: CGPointZero, size: CGSize(width: 16, height: 16)))
       let image = UIImage(ciImage: coreImage)
-      let modelContent = image.partsValue
+      let modelContent = try image.tryPartsValue()
       XCTAssert(modelContent.count > 0, "Expected non-empty model content for UIImage: \(image)")
     }
   #else
@@ -64,7 +64,7 @@ final class PartsRepresentableTests: XCTestCase {
       let rep = NSCIImageRep(ciImage: coreImage)
       let image = NSImage(size: rep.size)
       image.addRepresentation(rep)
-      let modelContent = image.partsValue
+      let modelContent = try image.tryPartsValue()
       XCTAssert(modelContent.count > 0, "Expected non-empty model content for NSImage: \(image)")
     }
   #endif

From 5088f30f04134434b89b4ed7fbb374a275c2b1c2 Mon Sep 17 00:00:00 2001
From: Morgan Chen <morganchen12@gmail.com>
Date: Fri, 19 Jan 2024 14:44:35 -0800
Subject: [PATCH 05/15] fix macos

---
 Sources/GoogleAI/PartsRepresentable+Image.swift | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/Sources/GoogleAI/PartsRepresentable+Image.swift b/Sources/GoogleAI/PartsRepresentable+Image.swift
index de12291..09a3fac 100644
--- a/Sources/GoogleAI/PartsRepresentable+Image.swift
+++ b/Sources/GoogleAI/PartsRepresentable+Image.swift
@@ -25,8 +25,10 @@ private let imageCompressionQuality: CGFloat = 0.8
 /// For some image types like `CIImage`, creating valid model content requires creating a JPEG
 /// representation of the image that may not yet exist, which may be computationally expensive.
 public enum ImageConversionError: Error {
-  /// The underlying image was invalid. The error will be accompanied by the actual image object.
-  case invalidUnderlyingImage(CGImage)
+  #if canImport(AppKit)
+    /// The image (the receiver of the call `toModelContentParts()`) was invalid.
+    case invalidUnderlyingImage
+  #endif
 
   /// A valid image destination could not be allocated.
   case couldNotAllocateDestination
@@ -52,7 +54,7 @@ public enum ImageConversionError: Error {
   extension NSImage: PartsRepresentable {
     public func toModelContentParts() -> Result<[ModelContent.Part], ImageConversionError> {
       guard let cgImage = cgImage(forProposedRect: nil, context: nil, hints: nil) else {
-        return .failure(.invalidUnderlyingImage(self))
+        return .failure(.invalidUnderlyingImage)
       }
       let bmp = NSBitmapImageRep(cgImage: cgImage)
       guard let data = bmp.representation(using: .jpeg, properties: [.compressionFactor: 0.8])

From 9913ae5a5f4386e66550860a101913935f0f1c9c Mon Sep 17 00:00:00 2001
From: Morgan Chen <morganchen12@gmail.com>
Date: Tue, 23 Jan 2024 16:04:13 -0800
Subject: [PATCH 06/15] put errors into api methods

---
 .../ChatSample/Views/ErrorDetailsView.swift   |  4 +-
 .../ChatSample/Views/ErrorView.swift          |  2 +-
 Sources/GoogleAI/Chat.swift                   | 22 +++++++++--
 Sources/GoogleAI/GenerativeModel.swift        | 13 ++++++-
 Sources/GoogleAI/ModelContent.swift           | 13 ++-----
 Tests/GoogleAITests/ChatTests.swift           |  2 +-
 Tests/GoogleAITests/GoogleAITests.swift       | 38 +++++++++----------
 7 files changed, 56 insertions(+), 38 deletions(-)

diff --git a/Examples/GenerativeAISample/ChatSample/Views/ErrorDetailsView.swift b/Examples/GenerativeAISample/ChatSample/Views/ErrorDetailsView.swift
index 5483f03..7f7e25c 100644
--- a/Examples/GenerativeAISample/ChatSample/Views/ErrorDetailsView.swift
+++ b/Examples/GenerativeAISample/ChatSample/Views/ErrorDetailsView.swift
@@ -162,7 +162,7 @@ struct ErrorDetailsView: View {
   NavigationView {
     let _ = GenerateContentError.promptBlocked(
       response: GenerateContentResponse(candidates: [
-        CandidateResponse(content: ModelContent(role: "model", [
+        CandidateResponse(content: try! ModelContent(role: "model", [
           """
             A _hypothetical_ model response.
             Cillum ex aliqua amet aliquip labore amet eiusmod consectetur reprehenderit sit commodo.
@@ -183,7 +183,7 @@ struct ErrorDetailsView: View {
     let errorFinishedEarly = GenerateContentError.responseStoppedEarly(
       reason: .maxTokens,
       response: GenerateContentResponse(candidates: [
-        CandidateResponse(content: ModelContent(role: "model", [
+        CandidateResponse(content: try! ModelContent(role: "model", [
           """
             A _hypothetical_ model response.
             Cillum ex aliqua amet aliquip labore amet eiusmod consectetur reprehenderit sit commodo.
diff --git a/Examples/GenerativeAISample/ChatSample/Views/ErrorView.swift b/Examples/GenerativeAISample/ChatSample/Views/ErrorView.swift
index aafdcd2..77abea6 100644
--- a/Examples/GenerativeAISample/ChatSample/Views/ErrorView.swift
+++ b/Examples/GenerativeAISample/ChatSample/Views/ErrorView.swift
@@ -37,7 +37,7 @@ struct ErrorView: View {
   NavigationView {
     let errorPromptBlocked = GenerateContentError.promptBlocked(
       response: GenerateContentResponse(candidates: [
-        CandidateResponse(content: ModelContent(role: "model", [
+        CandidateResponse(content: try! ModelContent(role: "model", [
           """
             A _hypothetical_ model response.
             Cillum ex aliqua amet aliquip labore amet eiusmod consectetur reprehenderit sit commodo.
diff --git a/Sources/GoogleAI/Chat.swift b/Sources/GoogleAI/Chat.swift
index 51c0fc4..78ecb1f 100644
--- a/Sources/GoogleAI/Chat.swift
+++ b/Sources/GoogleAI/Chat.swift
@@ -40,9 +40,14 @@ public class Chat {
   /// - Parameter content: The new content to send as a single chat message.
   /// - Returns: The model's response if no error occurred.
   /// - Throws: A ``GenerateContentError`` if an error occurred.
-  public func sendMessage(_ content: [ModelContent]) async throws -> GenerateContentResponse {
+  public func sendMessage(_ content: @autoclosure () throws -> [ModelContent]) async throws -> GenerateContentResponse {
     // Ensure that the new content has the role set.
-    let newContent: [ModelContent] = content.map(populateContentRole(_:))
+    let newContent: [ModelContent]
+    do {
+      newContent = try content().map(populateContentRole(_:))
+    } catch(let underlying) {
+      throw GenerateContentError.internalError(underlying: underlying)
+    }
 
     // Send the history alongside the new message as context.
     let request = history + newContent
@@ -69,7 +74,7 @@ public class Chat {
   @available(macOS 12.0, *)
   public func sendMessageStream(_ parts: any PartsRepresentable...)
     -> AsyncThrowingStream<GenerateContentResponse, Error> {
-    return sendMessageStream([ModelContent(parts: parts)])
+    return sendMessageStream(try [ModelContent(parts: parts)])
   }
 
   /// Sends a message using the existing history of this chat as context. If successful, the message
@@ -77,8 +82,17 @@ public class Chat {
   /// - Parameter content: The new content to send as a single chat message.
   /// - Returns: A stream containing the model's response or an error if an error occurred.
   @available(macOS 12.0, *)
-  public func sendMessageStream(_ content: [ModelContent])
+  public func sendMessageStream(_ contentClosure: @autoclosure () throws -> [ModelContent])
     -> AsyncThrowingStream<GenerateContentResponse, Error> {
+      let content: [ModelContent]
+      do {
+        content = try contentClosure()
+      } catch(let underlying) {
+        return AsyncThrowingStream { continuation in
+          continuation.finish(throwing: GenerateContentError.internalError(underlying: underlying))
+        }
+      }
+
     return AsyncThrowingStream { continuation in
       Task {
         var aggregatedContent: [ModelContent] = []
diff --git a/Sources/GoogleAI/GenerativeModel.swift b/Sources/GoogleAI/GenerativeModel.swift
index ea97053..e73811f 100644
--- a/Sources/GoogleAI/GenerativeModel.swift
+++ b/Sources/GoogleAI/GenerativeModel.swift
@@ -141,7 +141,7 @@ public final class GenerativeModel {
   @available(macOS 12.0, *)
   public func generateContentStream(_ parts: any PartsRepresentable...)
     -> AsyncThrowingStream<GenerateContentResponse, Error> {
-    return generateContentStream([ModelContent(parts: parts)])
+    return generateContentStream(try [ModelContent(parts: parts)])
   }
 
   /// Generates new content from input content given to the model as a prompt.
@@ -150,8 +150,17 @@ public final class GenerativeModel {
   /// - Returns: A stream wrapping content generated by the model or a ``GenerateContentError``
   ///     error if an error occurred.
   @available(macOS 12.0, *)
-  public func generateContentStream(_ content: [ModelContent])
+  public func generateContentStream(_ contentClosure: @autoclosure () throws -> [ModelContent])
     -> AsyncThrowingStream<GenerateContentResponse, Error> {
+      let content: [ModelContent]
+      do {
+        content = try contentClosure()
+      } catch(let underlying) {
+        return AsyncThrowingStream { continuation in
+          continuation.finish(throwing: GenerateContentError.internalError(underlying: underlying))
+        }
+      }
+
     let generateContentRequest = GenerateContentRequest(model: modelResourceName,
                                                         contents: content,
                                                         generationConfig: generationConfig,
diff --git a/Sources/GoogleAI/ModelContent.swift b/Sources/GoogleAI/ModelContent.swift
index df99efa..05148bf 100644
--- a/Sources/GoogleAI/ModelContent.swift
+++ b/Sources/GoogleAI/ModelContent.swift
@@ -104,14 +104,9 @@ public struct ModelContent: Codable, Equatable {
 
   /// Creates a new value from any data or `Array` of data interpretable as a
   /// ``Part``. See ``PartsRepresentable`` for types that can be interpreted as `Part`s.
-  public init(role: String? = "user", parts: some PartsRepresentable) {
+  public init(role: String? = "user", parts: some PartsRepresentable) throws {
     self.role = role
-    do {
-      try self.parts = parts.tryPartsValue()
-    } catch {
-      Logging.default.error("Error creating parts: \(error)")
-      self.parts = []
-    }
+    try self.parts = parts.tryPartsValue()
   }
 
   /// Creates a new value from a list of ``Part``s.
@@ -122,7 +117,7 @@ public struct ModelContent: Codable, Equatable {
 
   /// Creates a new value from any data interpretable as a ``Part``. See ``PartsRepresentable``
   /// for types that can be interpreted as `Part`s.
-  public init(role: String? = "user", _ parts: any PartsRepresentable...) {
-    self.init(role: role, parts: parts)
+  public init(role: String? = "user", _ parts: any PartsRepresentable...) throws {
+    try self.init(role: role, parts: parts)
   }
 }
diff --git a/Tests/GoogleAITests/ChatTests.swift b/Tests/GoogleAITests/ChatTests.swift
index 4020d4b..0757327 100644
--- a/Tests/GoogleAITests/ChatTests.swift
+++ b/Tests/GoogleAITests/ChatTests.swift
@@ -60,7 +60,7 @@ final class ChatTests: XCTestCase {
     XCTAssertEqual(chat.history[0].parts[0].text, input)
 
     let finalText = "1 2 3 4 5 6 7 8 9 10"
-    let assembledExpectation = ModelContent(role: "model", parts: finalText)
+    let assembledExpectation = try ModelContent(role: "model", parts: finalText)
     XCTAssertEqual(chat.history[0].parts[0].text, input)
     XCTAssertEqual(chat.history[1], assembledExpectation)
   }
diff --git a/Tests/GoogleAITests/GoogleAITests.swift b/Tests/GoogleAITests/GoogleAITests.swift
index 6389ddb..be84d46 100644
--- a/Tests/GoogleAITests/GoogleAITests.swift
+++ b/Tests/GoogleAITests/GoogleAITests.swift
@@ -69,8 +69,8 @@ final class GoogleGenerativeAITests: XCTestCase {
         .generateContent([str, UIImage(), ModelContent.Part.text(str)])
       _ = try await genAI.generateContent(str, UIImage(), "def", UIImage())
       _ = try await genAI.generateContent([str, UIImage(), "def", UIImage()])
-      _ = try await genAI.generateContent([ModelContent("def", UIImage()),
-                                           ModelContent("def", UIImage())])
+      _ = try await genAI.generateContent([try ModelContent("def", UIImage()),
+                                           try ModelContent("def", UIImage())])
     #elseif canImport(AppKit)
       _ = try await genAI.generateContent(NSImage())
       _ = try await genAI.generateContent([NSImage()])
@@ -81,40 +81,40 @@ final class GoogleGenerativeAITests: XCTestCase {
     // PartsRepresentable combinations.
     let _ = ModelContent(parts: [.text(str)])
     let _ = ModelContent(role: "model", parts: [.text(str)])
-    let _ = ModelContent(parts: "Constant String")
-    let _ = ModelContent(parts: str)
-    let _ = ModelContent(parts: [str])
+    let _ = try ModelContent(parts: "Constant String")
+    let _ = try ModelContent(parts: str)
+    let _ = try ModelContent(parts: [str])
     // Note: without `as [any PartsRepresentable]` this will fail to compile with "Cannot convert
     // value of type `[Any]` to expected type `[any PartsRepresentable]`. Not sure if there's a
     // way we can get it to work.
-    let _ = ModelContent(parts: [str, ModelContent.Part.data(
+    let _ = try ModelContent(parts: [str, ModelContent.Part.data(
       mimetype: "foo",
       Data()
     )] as [any PartsRepresentable])
     #if canImport(UIKit)
-      _ = ModelContent(role: "user", parts: UIImage())
-      _ = ModelContent(role: "user", parts: [UIImage()])
+      _ = try ModelContent(role: "user", parts: UIImage())
+      _ = try ModelContent(role: "user", parts: [UIImage()])
       // Note: without `as [any PartsRepresentable]` this will fail to compile with "Cannot convert
       // value of type `[Any]` to expected type `[any PartsRepresentable]`. Not sure if there's a
       // way we can get it to work.
-      _ = ModelContent(parts: [str, UIImage()] as [any PartsRepresentable])
+      _ = try ModelContent(parts: [str, UIImage()] as [any PartsRepresentable])
       // Alternatively, you can explicitly declare the type in a variable and pass it in.
       let representable2: [any PartsRepresentable] = [str, UIImage()]
-      _ = ModelContent(parts: representable2)
-      _ = ModelContent(parts: [str, UIImage(),
+      _ = try ModelContent(parts: representable2)
+      _ = try ModelContent(parts: [str, UIImage(),
                                ModelContent.Part.text(str)] as [any PartsRepresentable])
     #elseif canImport(AppKit)
-      _ = ModelContent(role: "user", parts: NSImage())
-      _ = ModelContent(role: "user", parts: [NSImage()])
+      _ = try ModelContent(role: "user", parts: NSImage())
+      _ = try ModelContent(role: "user", parts: [NSImage()])
       // Note: without `as [any PartsRepresentable]` this will fail to compile with "Cannot convert
       // value of type `[Any]` to expected type `[any PartsRepresentable]`. Not sure if there's a
       // way we can get it to work.
-      _ = ModelContent(parts: [str, NSImage()] as [any PartsRepresentable])
+      _ = try ModelContent(parts: [str, NSImage()] as [any PartsRepresentable])
       // Alternatively, you can explicitly declare the type in a variable and pass it in.
       let representable2: [any PartsRepresentable] = [str, NSImage()]
-      _ = ModelContent(parts: representable2)
+      _ = try ModelContent(parts: representable2)
       _ =
-        ModelContent(parts: [str, NSImage(),
+        try ModelContent(parts: [str, NSImage(),
                              ModelContent.Part.text(str)] as [any PartsRepresentable])
     #endif
 
@@ -124,14 +124,14 @@ final class GoogleGenerativeAITests: XCTestCase {
       let _: CountTokensResponse = try await genAI.countTokens("What color is the Sky?",
                                                                UIImage())
       let _: CountTokensResponse = try await genAI.countTokens([
-        ModelContent("What color is the Sky?", UIImage()),
-        ModelContent(UIImage(), "What color is the Sky?", UIImage()),
+        try ModelContent("What color is the Sky?", UIImage()),
+        try ModelContent(UIImage(), "What color is the Sky?", UIImage()),
       ])
     #endif
 
     // Chat
     _ = genAI.startChat()
-    _ = genAI.startChat(history: [ModelContent(parts: "abc")])
+    _ = genAI.startChat(history: [try ModelContent(parts: "abc")])
   }
 
   // Result builder alternative

From 4b0a290e002fbe78cbbdd0d7108fbc1be33bc6f4 Mon Sep 17 00:00:00 2001
From: Morgan Chen <morganchen12@gmail.com>
Date: Tue, 23 Jan 2024 16:04:46 -0800
Subject: [PATCH 07/15] style

---
 Sources/GoogleAI/Chat.swift             | 21 +++++++++++----------
 Sources/GoogleAI/GenerativeModel.swift  | 16 ++++++++--------
 Tests/GoogleAITests/GoogleAITests.swift | 14 +++++++-------
 3 files changed, 26 insertions(+), 25 deletions(-)

diff --git a/Sources/GoogleAI/Chat.swift b/Sources/GoogleAI/Chat.swift
index 78ecb1f..daf5ea0 100644
--- a/Sources/GoogleAI/Chat.swift
+++ b/Sources/GoogleAI/Chat.swift
@@ -40,12 +40,13 @@ public class Chat {
   /// - Parameter content: The new content to send as a single chat message.
   /// - Returns: The model's response if no error occurred.
   /// - Throws: A ``GenerateContentError`` if an error occurred.
-  public func sendMessage(_ content: @autoclosure () throws -> [ModelContent]) async throws -> GenerateContentResponse {
+  public func sendMessage(_ content: @autoclosure () throws -> [ModelContent]) async throws
+    -> GenerateContentResponse {
     // Ensure that the new content has the role set.
     let newContent: [ModelContent]
     do {
       newContent = try content().map(populateContentRole(_:))
-    } catch(let underlying) {
+    } catch let underlying {
       throw GenerateContentError.internalError(underlying: underlying)
     }
 
@@ -74,7 +75,7 @@ public class Chat {
   @available(macOS 12.0, *)
   public func sendMessageStream(_ parts: any PartsRepresentable...)
     -> AsyncThrowingStream<GenerateContentResponse, Error> {
-    return sendMessageStream(try [ModelContent(parts: parts)])
+    return try sendMessageStream([ModelContent(parts: parts)])
   }
 
   /// Sends a message using the existing history of this chat as context. If successful, the message
@@ -84,14 +85,14 @@ public class Chat {
   @available(macOS 12.0, *)
   public func sendMessageStream(_ contentClosure: @autoclosure () throws -> [ModelContent])
     -> AsyncThrowingStream<GenerateContentResponse, Error> {
-      let content: [ModelContent]
-      do {
-        content = try contentClosure()
-      } catch(let underlying) {
-        return AsyncThrowingStream { continuation in
-          continuation.finish(throwing: GenerateContentError.internalError(underlying: underlying))
-        }
+    let content: [ModelContent]
+    do {
+      content = try contentClosure()
+    } catch let underlying {
+      return AsyncThrowingStream { continuation in
+        continuation.finish(throwing: GenerateContentError.internalError(underlying: underlying))
       }
+    }
 
     return AsyncThrowingStream { continuation in
       Task {
diff --git a/Sources/GoogleAI/GenerativeModel.swift b/Sources/GoogleAI/GenerativeModel.swift
index e73811f..6676a7f 100644
--- a/Sources/GoogleAI/GenerativeModel.swift
+++ b/Sources/GoogleAI/GenerativeModel.swift
@@ -141,7 +141,7 @@ public final class GenerativeModel {
   @available(macOS 12.0, *)
   public func generateContentStream(_ parts: any PartsRepresentable...)
     -> AsyncThrowingStream<GenerateContentResponse, Error> {
-    return generateContentStream(try [ModelContent(parts: parts)])
+    return try generateContentStream([ModelContent(parts: parts)])
   }
 
   /// Generates new content from input content given to the model as a prompt.
@@ -152,14 +152,14 @@ public final class GenerativeModel {
   @available(macOS 12.0, *)
   public func generateContentStream(_ contentClosure: @autoclosure () throws -> [ModelContent])
     -> AsyncThrowingStream<GenerateContentResponse, Error> {
-      let content: [ModelContent]
-      do {
-        content = try contentClosure()
-      } catch(let underlying) {
-        return AsyncThrowingStream { continuation in
-          continuation.finish(throwing: GenerateContentError.internalError(underlying: underlying))
-        }
+    let content: [ModelContent]
+    do {
+      content = try contentClosure()
+    } catch let underlying {
+      return AsyncThrowingStream { continuation in
+        continuation.finish(throwing: GenerateContentError.internalError(underlying: underlying))
       }
+    }
 
     let generateContentRequest = GenerateContentRequest(model: modelResourceName,
                                                         contents: content,
diff --git a/Tests/GoogleAITests/GoogleAITests.swift b/Tests/GoogleAITests/GoogleAITests.swift
index be84d46..ea8250e 100644
--- a/Tests/GoogleAITests/GoogleAITests.swift
+++ b/Tests/GoogleAITests/GoogleAITests.swift
@@ -69,8 +69,8 @@ final class GoogleGenerativeAITests: XCTestCase {
         .generateContent([str, UIImage(), ModelContent.Part.text(str)])
       _ = try await genAI.generateContent(str, UIImage(), "def", UIImage())
       _ = try await genAI.generateContent([str, UIImage(), "def", UIImage()])
-      _ = try await genAI.generateContent([try ModelContent("def", UIImage()),
-                                           try ModelContent("def", UIImage())])
+      _ = try await genAI.generateContent([ModelContent("def", UIImage()),
+                                           ModelContent("def", UIImage())])
     #elseif canImport(AppKit)
       _ = try await genAI.generateContent(NSImage())
       _ = try await genAI.generateContent([NSImage()])
@@ -102,7 +102,7 @@ final class GoogleGenerativeAITests: XCTestCase {
       let representable2: [any PartsRepresentable] = [str, UIImage()]
       _ = try ModelContent(parts: representable2)
       _ = try ModelContent(parts: [str, UIImage(),
-                               ModelContent.Part.text(str)] as [any PartsRepresentable])
+                                   ModelContent.Part.text(str)] as [any PartsRepresentable])
     #elseif canImport(AppKit)
       _ = try ModelContent(role: "user", parts: NSImage())
       _ = try ModelContent(role: "user", parts: [NSImage()])
@@ -115,7 +115,7 @@ final class GoogleGenerativeAITests: XCTestCase {
       _ = try ModelContent(parts: representable2)
       _ =
         try ModelContent(parts: [str, NSImage(),
-                             ModelContent.Part.text(str)] as [any PartsRepresentable])
+                                 ModelContent.Part.text(str)] as [any PartsRepresentable])
     #endif
 
     // countTokens API
@@ -124,14 +124,14 @@ final class GoogleGenerativeAITests: XCTestCase {
       let _: CountTokensResponse = try await genAI.countTokens("What color is the Sky?",
                                                                UIImage())
       let _: CountTokensResponse = try await genAI.countTokens([
-        try ModelContent("What color is the Sky?", UIImage()),
-        try ModelContent(UIImage(), "What color is the Sky?", UIImage()),
+        ModelContent("What color is the Sky?", UIImage()),
+        ModelContent(UIImage(), "What color is the Sky?", UIImage()),
       ])
     #endif
 
     // Chat
     _ = genAI.startChat()
-    _ = genAI.startChat(history: [try ModelContent(parts: "abc")])
+    _ = try genAI.startChat(history: [ModelContent(parts: "abc")])
   }
 
   // Result builder alternative

From a68afb4e481ce0a20bc1a9f6f757c05a9c784c19 Mon Sep 17 00:00:00 2001
From: Morgan Chen <morganchen12@gmail.com>
Date: Thu, 25 Jan 2024 15:32:02 -0800
Subject: [PATCH 08/15] remove generic error

---
 .../GoogleAI/PartsRepresentable+Image.swift   | 28 ++++++------
 Sources/GoogleAI/PartsRepresentable.swift     | 44 +++++--------------
 2 files changed, 24 insertions(+), 48 deletions(-)

diff --git a/Sources/GoogleAI/PartsRepresentable+Image.swift b/Sources/GoogleAI/PartsRepresentable+Image.swift
index 09a3fac..3fe33a2 100644
--- a/Sources/GoogleAI/PartsRepresentable+Image.swift
+++ b/Sources/GoogleAI/PartsRepresentable+Image.swift
@@ -41,52 +41,52 @@ public enum ImageConversionError: Error {
 #if canImport(UIKit)
   /// Enables images to be representable as ``PartsRepresentable``.
   extension UIImage: PartsRepresentable {
-    public func toModelContentParts() -> Result<[ModelContent.Part], ImageConversionError> {
+    public func tryPartsValue() throws -> [ModelContent.Part] {
       guard let data = jpegData(compressionQuality: imageCompressionQuality) else {
-        return .failure(.couldNotConvertToJPEG(self))
+        throw ImageConversionError.couldNotConvertToJPEG(self)
       }
-      return .success([ModelContent.Part.data(mimetype: "image/jpeg", data)])
+      return [ModelContent.Part.data(mimetype: "image/jpeg", data)]
     }
   }
 
 #elseif canImport(AppKit)
   /// Enables images to be representable as ``PartsRepresentable``.
   extension NSImage: PartsRepresentable {
-    public func toModelContentParts() -> Result<[ModelContent.Part], ImageConversionError> {
+    public func tryPartsValue() throws -> [ModelContent.Part] {
       guard let cgImage = cgImage(forProposedRect: nil, context: nil, hints: nil) else {
-        return .failure(.invalidUnderlyingImage)
+        throw ImageConversionError.invalidUnderlyingImage
       }
       let bmp = NSBitmapImageRep(cgImage: cgImage)
       guard let data = bmp.representation(using: .jpeg, properties: [.compressionFactor: 0.8])
       else {
-        return .failure(.couldNotConvertToJPEG(bmp))
+        throw ImageConversionError.couldNotConvertToJPEG(bmp)
       }
-      return .success([ModelContent.Part.data(mimetype: "image/jpeg", data)])
+      return [ModelContent.Part.data(mimetype: "image/jpeg", data)]
     }
   }
 #endif
 
 extension CGImage: PartsRepresentable {
-  public func toModelContentParts() -> Result<[ModelContent.Part], ImageConversionError> {
+  public func tryPartsValue() throws -> [ModelContent.Part] {
     let output = NSMutableData()
     guard let imageDestination = CGImageDestinationCreateWithData(
       output, UTType.jpeg.identifier as CFString, 1, nil
     ) else {
-      return .failure(.couldNotAllocateDestination)
+      throw ImageConversionError.couldNotAllocateDestination
     }
     CGImageDestinationAddImage(imageDestination, self, nil)
     CGImageDestinationSetProperties(imageDestination, [
       kCGImageDestinationLossyCompressionQuality: imageCompressionQuality,
     ] as CFDictionary)
     if CGImageDestinationFinalize(imageDestination) {
-      return .success([.data(mimetype: "image/jpeg", output as Data)])
+      return [.data(mimetype: "image/jpeg", output as Data)]
     }
-    return .failure(.couldNotConvertToJPEG(self))
+    throw ImageConversionError.couldNotConvertToJPEG(self)
   }
 }
 
 extension CIImage: PartsRepresentable {
-  public func toModelContentParts() -> Result<[ModelContent.Part], ImageConversionError> {
+  public func tryPartsValue() throws -> [ModelContent.Part] {
     let context = CIContext()
     let jpegData = (colorSpace ?? CGColorSpace(name: CGColorSpace.sRGB))
       .flatMap {
@@ -96,8 +96,8 @@ extension CIImage: PartsRepresentable {
         context.jpegRepresentation(of: self, colorSpace: $0, options: [:])
       }
     if let jpegData = jpegData {
-      return .success([.data(mimetype: "image/jpeg", jpegData)])
+      return [.data(mimetype: "image/jpeg", jpegData)]
     }
-    return .failure(.couldNotConvertToJPEG(self))
+    throw ImageConversionError.couldNotConvertToJPEG(self)
   }
 }
diff --git a/Sources/GoogleAI/PartsRepresentable.swift b/Sources/GoogleAI/PartsRepresentable.swift
index deaf5a9..cbdda35 100644
--- a/Sources/GoogleAI/PartsRepresentable.swift
+++ b/Sources/GoogleAI/PartsRepresentable.swift
@@ -17,55 +17,31 @@ import Foundation
 /// A protocol describing any data that could be serialized to model-interpretable input data,
 /// where the serialization process might fail with an error.
 public protocol PartsRepresentable {
-  associatedtype ErrorType where ErrorType: Error
-  func toModelContentParts() -> Result<[ModelContent.Part], ErrorType>
-}
-
-public extension PartsRepresentable {
-  func tryPartsValue() throws -> [ModelContent.Part] {
-    return try toModelContentParts().get()
-  }
-}
-
-public extension PartsRepresentable where ErrorType == Never {
-  var partsValue: [ModelContent.Part] {
-    let content = toModelContentParts()
-    switch content {
-    case let .success(success):
-      return success
-    }
-  }
+  func tryPartsValue() throws -> [ModelContent.Part]
 }
 
 /// Enables a ``ModelContent.Part`` to be passed in as ``PartsRepresentable``.
 extension ModelContent.Part: PartsRepresentable {
   public typealias ErrorType = Never
-  public func toModelContentParts() -> Result<[ModelContent.Part], Never> {
-    return .success([self])
+  public func tryPartsValue() throws -> [ModelContent.Part] {
+    return [self]
   }
 }
 
 /// Enable an `Array` of ``PartsRepresentable`` values to be passed in as a single
 /// ``PartsRepresentable``.
-extension [any PartsRepresentable]: PartsRepresentable {
-  public typealias ErrorType = Error
-
-  public func toModelContentParts() -> Result<[ModelContent.Part], Error> {
-    let result = { () throws -> [ModelContent.Part] in
-      try compactMap { element in
-        try element.tryPartsValue()
-      }
-      .flatMap { $0 }
+extension [PartsRepresentable]: PartsRepresentable {
+  public func tryPartsValue() throws -> [ModelContent.Part] {
+    return try compactMap { element in
+      try element.tryPartsValue()
     }
-    return Result(catching: result)
+    .flatMap { $0 }
   }
 }
 
 /// Enables a `String` to be passed in as ``PartsRepresentable``.
 extension String: PartsRepresentable {
-  public typealias ErrorType = Never
-
-  public func toModelContentParts() -> Result<[ModelContent.Part], Never> {
-    return .success([.text(self)])
+  public func tryPartsValue() throws -> [ModelContent.Part] {
+    return [.text(self)]
   }
 }

From 0a8fa14a91a0c25e9ef56ca449857e0b5600afb8 Mon Sep 17 00:00:00 2001
From: Morgan Chen <morganchen12@gmail.com>
Date: Thu, 25 Jan 2024 16:28:35 -0800
Subject: [PATCH 09/15] add non-erroring protocol so force unwraps arent
 required

---
 .../ChatSample/Views/ErrorDetailsView.swift   |  4 +-
 .../ChatSample/Views/ErrorView.swift          |  2 +-
 .../ViewModels/PhotoReasoningViewModel.swift  |  2 +-
 Sources/GoogleAI/Chat.swift                   |  4 +-
 Sources/GoogleAI/GenerativeModel.swift        | 16 ++++---
 Sources/GoogleAI/ModelContent.swift           | 27 +++++++++---
 .../GoogleAI/PartsRepresentable+Image.swift   | 12 +++---
 Sources/GoogleAI/PartsRepresentable.swift     | 29 +++++++++----
 Tests/GoogleAITests/ChatTests.swift           |  2 +-
 Tests/GoogleAITests/GoogleAITests.swift       | 43 +++++++++++--------
 .../PartsRepresentableTests.swift             |  2 +-
 11 files changed, 92 insertions(+), 51 deletions(-)

diff --git a/Examples/GenerativeAISample/ChatSample/Views/ErrorDetailsView.swift b/Examples/GenerativeAISample/ChatSample/Views/ErrorDetailsView.swift
index 7f7e25c..5483f03 100644
--- a/Examples/GenerativeAISample/ChatSample/Views/ErrorDetailsView.swift
+++ b/Examples/GenerativeAISample/ChatSample/Views/ErrorDetailsView.swift
@@ -162,7 +162,7 @@ struct ErrorDetailsView: View {
   NavigationView {
     let _ = GenerateContentError.promptBlocked(
       response: GenerateContentResponse(candidates: [
-        CandidateResponse(content: try! ModelContent(role: "model", [
+        CandidateResponse(content: ModelContent(role: "model", [
           """
             A _hypothetical_ model response.
             Cillum ex aliqua amet aliquip labore amet eiusmod consectetur reprehenderit sit commodo.
@@ -183,7 +183,7 @@ struct ErrorDetailsView: View {
     let errorFinishedEarly = GenerateContentError.responseStoppedEarly(
       reason: .maxTokens,
       response: GenerateContentResponse(candidates: [
-        CandidateResponse(content: try! ModelContent(role: "model", [
+        CandidateResponse(content: ModelContent(role: "model", [
           """
             A _hypothetical_ model response.
             Cillum ex aliqua amet aliquip labore amet eiusmod consectetur reprehenderit sit commodo.
diff --git a/Examples/GenerativeAISample/ChatSample/Views/ErrorView.swift b/Examples/GenerativeAISample/ChatSample/Views/ErrorView.swift
index 77abea6..aafdcd2 100644
--- a/Examples/GenerativeAISample/ChatSample/Views/ErrorView.swift
+++ b/Examples/GenerativeAISample/ChatSample/Views/ErrorView.swift
@@ -37,7 +37,7 @@ struct ErrorView: View {
   NavigationView {
     let errorPromptBlocked = GenerateContentError.promptBlocked(
       response: GenerateContentResponse(candidates: [
-        CandidateResponse(content: try! ModelContent(role: "model", [
+        CandidateResponse(content: ModelContent(role: "model", [
           """
             A _hypothetical_ model response.
             Cillum ex aliqua amet aliquip labore amet eiusmod consectetur reprehenderit sit commodo.
diff --git a/Examples/GenerativeAISample/GenerativeAIMultimodalSample/ViewModels/PhotoReasoningViewModel.swift b/Examples/GenerativeAISample/GenerativeAIMultimodalSample/ViewModels/PhotoReasoningViewModel.swift
index 0822175..d434557 100644
--- a/Examples/GenerativeAISample/GenerativeAIMultimodalSample/ViewModels/PhotoReasoningViewModel.swift
+++ b/Examples/GenerativeAISample/GenerativeAIMultimodalSample/ViewModels/PhotoReasoningViewModel.swift
@@ -58,7 +58,7 @@ class PhotoReasoningViewModel: ObservableObject {
 
       let prompt = "Look at the image(s), and then answer the following question: \(userInput)"
 
-      var images = [any PartsRepresentable]()
+      var images = [any ThrowingPartsRepresentable]()
       for item in selectedItems {
         if let data = try? await item.loadTransferable(type: Data.self) {
           images.append(ModelContent.Part.png(data))
diff --git a/Sources/GoogleAI/Chat.swift b/Sources/GoogleAI/Chat.swift
index daf5ea0..1fc3a67 100644
--- a/Sources/GoogleAI/Chat.swift
+++ b/Sources/GoogleAI/Chat.swift
@@ -30,7 +30,7 @@ public class Chat {
   public var history: [ModelContent]
 
   /// See ``sendMessage(_:)-3ify5``.
-  public func sendMessage(_ parts: any PartsRepresentable...) async throws
+  public func sendMessage(_ parts: any ThrowingPartsRepresentable...) async throws
     -> GenerateContentResponse {
     return try await sendMessage([ModelContent(parts: parts)])
   }
@@ -73,7 +73,7 @@ public class Chat {
 
   /// See ``sendMessageStream(_:)-4abs3``.
   @available(macOS 12.0, *)
-  public func sendMessageStream(_ parts: any PartsRepresentable...)
+  public func sendMessageStream(_ parts: any ThrowingPartsRepresentable...)
     -> AsyncThrowingStream<GenerateContentResponse, Error> {
     return try sendMessageStream([ModelContent(parts: parts)])
   }
diff --git a/Sources/GoogleAI/GenerativeModel.swift b/Sources/GoogleAI/GenerativeModel.swift
index 6676a7f..d2c25bf 100644
--- a/Sources/GoogleAI/GenerativeModel.swift
+++ b/Sources/GoogleAI/GenerativeModel.swift
@@ -84,11 +84,12 @@ public final class GenerativeModel {
   /// [few-shot](https://developers.google.com/machine-learning/glossary/generative#few-shot-prompting)
   /// prompts, see ``generateContent(_:)-58rm0``.
   ///
-  /// - Parameter content: The input(s) given to the model as a prompt (see ``PartsRepresentable``
+  /// - Parameter content: The input(s) given to the model as a prompt (see
+  /// ``ThrowingPartsRepresentable``
   /// for conforming types).
   /// - Returns: The content generated by the model.
   /// - Throws: A ``GenerateContentError`` if the request failed.
-  public func generateContent(_ parts: any PartsRepresentable...)
+  public func generateContent(_ parts: any ThrowingPartsRepresentable...)
     async throws -> GenerateContentResponse {
     return try await generateContent([ModelContent(parts: parts)])
   }
@@ -134,12 +135,13 @@ public final class GenerativeModel {
   /// [few-shot](https://developers.google.com/machine-learning/glossary/generative#few-shot-prompting)
   /// prompts, see ``generateContent(_:)-58rm0``.
   ///
-  /// - Parameter content: The input(s) given to the model as a prompt (see ``PartsRepresentable``
+  /// - Parameter content: The input(s) given to the model as a prompt (see
+  /// ``ThrowingPartsRepresentable``
   /// for conforming types).
   /// - Returns: A stream wrapping content generated by the model or a ``GenerateContentError``
   ///     error if an error occurred.
   @available(macOS 12.0, *)
-  public func generateContentStream(_ parts: any PartsRepresentable...)
+  public func generateContentStream(_ parts: any ThrowingPartsRepresentable...)
     -> AsyncThrowingStream<GenerateContentResponse, Error> {
     return try generateContentStream([ModelContent(parts: parts)])
   }
@@ -212,12 +214,14 @@ public final class GenerativeModel {
   /// [few-shot](https://developers.google.com/machine-learning/glossary/generative#few-shot-prompting)
   /// input, see ``countTokens(_:)-9spwl``.
   ///
-  /// - Parameter content: The input(s) given to the model as a prompt (see ``PartsRepresentable``
+  /// - Parameter content: The input(s) given to the model as a prompt (see
+  /// ``ThrowingPartsRepresentable``
   /// for conforming types).
   /// - Returns: The results of running the model's tokenizer on the input; contains
   /// ``CountTokensResponse/totalTokens``.
   /// - Throws: A ``CountTokensError`` if the tokenization request failed.
-  public func countTokens(_ parts: any PartsRepresentable...) async throws -> CountTokensResponse {
+  public func countTokens(_ parts: any ThrowingPartsRepresentable...) async throws
+    -> CountTokensResponse {
     return try await countTokens([ModelContent(parts: parts)])
   }
 
diff --git a/Sources/GoogleAI/ModelContent.swift b/Sources/GoogleAI/ModelContent.swift
index 05148bf..ba4960e 100644
--- a/Sources/GoogleAI/ModelContent.swift
+++ b/Sources/GoogleAI/ModelContent.swift
@@ -103,21 +103,38 @@ public struct ModelContent: Codable, Equatable {
   public let parts: [Part]
 
   /// Creates a new value from any data or `Array` of data interpretable as a
-  /// ``Part``. See ``PartsRepresentable`` for types that can be interpreted as `Part`s.
-  public init(role: String? = "user", parts: some PartsRepresentable) throws {
+  /// ``Part``. See ``ThrowingPartsRepresentable`` for types that can be interpreted as `Part`s.
+  public init(role: String? = "user", parts: some ThrowingPartsRepresentable) throws {
     self.role = role
     try self.parts = parts.tryPartsValue()
   }
 
+  /// Creates a new value from any data or `Array` of data interpretable as a
+  /// ``Part``. See ``ThrowingPartsRepresentable`` for types that can be interpreted as `Part`s.
+  public init(role: String? = "user", parts: some PartsRepresentable) {
+    self.role = role
+    self.parts = parts.toPartsValue()
+  }
+
   /// Creates a new value from a list of ``Part``s.
   public init(role: String? = "user", parts: [Part]) {
     self.role = role
     self.parts = parts
   }
 
-  /// Creates a new value from any data interpretable as a ``Part``. See ``PartsRepresentable``
+  /// Creates a new value from any data interpretable as a ``Part``. See
+  /// ``ThrowingPartsRepresentable``
+  /// for types that can be interpreted as `Part`s.
+  public init(role: String? = "user", _ parts: any ThrowingPartsRepresentable...) throws {
+    let content = try parts.flatMap { try $0.tryPartsValue() }
+    self.init(role: role, parts: content)
+  }
+
+  /// Creates a new value from any data interpretable as a ``Part``. See
+  /// ``ThrowingPartsRepresentable``
   /// for types that can be interpreted as `Part`s.
-  public init(role: String? = "user", _ parts: any PartsRepresentable...) throws {
-    try self.init(role: role, parts: parts)
+  public init(role: String? = "user", _ parts: [PartsRepresentable]) {
+    let content = parts.flatMap { $0.toPartsValue() }
+    self.init(role: role, parts: content)
   }
 }
diff --git a/Sources/GoogleAI/PartsRepresentable+Image.swift b/Sources/GoogleAI/PartsRepresentable+Image.swift
index 3fe33a2..f9c699c 100644
--- a/Sources/GoogleAI/PartsRepresentable+Image.swift
+++ b/Sources/GoogleAI/PartsRepresentable+Image.swift
@@ -39,8 +39,8 @@ public enum ImageConversionError: Error {
 }
 
 #if canImport(UIKit)
-  /// Enables images to be representable as ``PartsRepresentable``.
-  extension UIImage: PartsRepresentable {
+  /// Enables images to be representable as ``ThrowingPartsRepresentable``.
+  extension UIImage: ThrowingPartsRepresentable {
     public func tryPartsValue() throws -> [ModelContent.Part] {
       guard let data = jpegData(compressionQuality: imageCompressionQuality) else {
         throw ImageConversionError.couldNotConvertToJPEG(self)
@@ -50,8 +50,8 @@ public enum ImageConversionError: Error {
   }
 
 #elseif canImport(AppKit)
-  /// Enables images to be representable as ``PartsRepresentable``.
-  extension NSImage: PartsRepresentable {
+  /// Enables images to be representable as ``ThrowingPartsRepresentable``.
+  extension NSImage: ThrowingPartsRepresentable {
     public func tryPartsValue() throws -> [ModelContent.Part] {
       guard let cgImage = cgImage(forProposedRect: nil, context: nil, hints: nil) else {
         throw ImageConversionError.invalidUnderlyingImage
@@ -66,7 +66,7 @@ public enum ImageConversionError: Error {
   }
 #endif
 
-extension CGImage: PartsRepresentable {
+extension CGImage: ThrowingPartsRepresentable {
   public func tryPartsValue() throws -> [ModelContent.Part] {
     let output = NSMutableData()
     guard let imageDestination = CGImageDestinationCreateWithData(
@@ -85,7 +85,7 @@ extension CGImage: PartsRepresentable {
   }
 }
 
-extension CIImage: PartsRepresentable {
+extension CIImage: ThrowingPartsRepresentable {
   public func tryPartsValue() throws -> [ModelContent.Part] {
     let context = CIContext()
     let jpegData = (colorSpace ?? CGColorSpace(name: CGColorSpace.sRGB))
diff --git a/Sources/GoogleAI/PartsRepresentable.swift b/Sources/GoogleAI/PartsRepresentable.swift
index cbdda35..a5afd80 100644
--- a/Sources/GoogleAI/PartsRepresentable.swift
+++ b/Sources/GoogleAI/PartsRepresentable.swift
@@ -16,21 +16,34 @@ import Foundation
 
 /// A protocol describing any data that could be serialized to model-interpretable input data,
 /// where the serialization process might fail with an error.
-public protocol PartsRepresentable {
+public protocol ThrowingPartsRepresentable {
   func tryPartsValue() throws -> [ModelContent.Part]
 }
 
-/// Enables a ``ModelContent.Part`` to be passed in as ``PartsRepresentable``.
-extension ModelContent.Part: PartsRepresentable {
+/// A protocol describing any data that could be serialized to model-interpretable input data,
+/// where the serialization process cannot fail with an error. For a failable conversion, see
+/// ``ThrowingPartsRepresentable``
+public protocol PartsRepresentable: ThrowingPartsRepresentable {
+  func toPartsValue() -> [ModelContent.Part]
+}
+
+public extension PartsRepresentable {
+  func tryPartsValue() throws -> [ModelContent.Part] {
+    return toPartsValue()
+  }
+}
+
+/// Enables a ``ModelContent.Part`` to be passed in as ``ThrowingPartsRepresentable``.
+extension ModelContent.Part: ThrowingPartsRepresentable {
   public typealias ErrorType = Never
   public func tryPartsValue() throws -> [ModelContent.Part] {
     return [self]
   }
 }
 
-/// Enable an `Array` of ``PartsRepresentable`` values to be passed in as a single
-/// ``PartsRepresentable``.
-extension [PartsRepresentable]: PartsRepresentable {
+/// Enable an `Array` of ``ThrowingPartsRepresentable`` values to be passed in as a single
+/// ``ThrowingPartsRepresentable``.
+extension [ThrowingPartsRepresentable]: ThrowingPartsRepresentable {
   public func tryPartsValue() throws -> [ModelContent.Part] {
     return try compactMap { element in
       try element.tryPartsValue()
@@ -39,9 +52,9 @@ extension [PartsRepresentable]: PartsRepresentable {
   }
 }
 
-/// Enables a `String` to be passed in as ``PartsRepresentable``.
+/// Enables a `String` to be passed in as ``ThrowingPartsRepresentable``.
 extension String: PartsRepresentable {
-  public func tryPartsValue() throws -> [ModelContent.Part] {
+  public func toPartsValue() -> [ModelContent.Part] {
     return [.text(self)]
   }
 }
diff --git a/Tests/GoogleAITests/ChatTests.swift b/Tests/GoogleAITests/ChatTests.swift
index 0757327..4020d4b 100644
--- a/Tests/GoogleAITests/ChatTests.swift
+++ b/Tests/GoogleAITests/ChatTests.swift
@@ -60,7 +60,7 @@ final class ChatTests: XCTestCase {
     XCTAssertEqual(chat.history[0].parts[0].text, input)
 
     let finalText = "1 2 3 4 5 6 7 8 9 10"
-    let assembledExpectation = try ModelContent(role: "model", parts: finalText)
+    let assembledExpectation = ModelContent(role: "model", parts: finalText)
     XCTAssertEqual(chat.history[0].parts[0].text, input)
     XCTAssertEqual(chat.history[1], assembledExpectation)
   }
diff --git a/Tests/GoogleAITests/GoogleAITests.swift b/Tests/GoogleAITests/GoogleAITests.swift
index ea8250e..f063be3 100644
--- a/Tests/GoogleAITests/GoogleAITests.swift
+++ b/Tests/GoogleAITests/GoogleAITests.swift
@@ -78,44 +78,51 @@ final class GoogleGenerativeAITests: XCTestCase {
       _ = try await genAI.generateContent([str, NSImage(), "def", NSImage()])
     #endif
 
-    // PartsRepresentable combinations.
+    // ThrowingPartsRepresentable combinations.
     let _ = ModelContent(parts: [.text(str)])
     let _ = ModelContent(role: "model", parts: [.text(str)])
-    let _ = try ModelContent(parts: "Constant String")
-    let _ = try ModelContent(parts: str)
+    let _ = ModelContent(parts: "Constant String")
+    let _ = ModelContent(parts: str)
+    // Note: This requires the `try` for some reason. Casting to explicit [PartsRepresentable] also
+    // doesn't work.
     let _ = try ModelContent(parts: [str])
-    // Note: without `as [any PartsRepresentable]` this will fail to compile with "Cannot convert
-    // value of type `[Any]` to expected type `[any PartsRepresentable]`. Not sure if there's a
-    // way we can get it to work.
+    // Note: without `as [any ThrowingPartsRepresentable]` this will fail to compile with "Cannot
+    // convert value of type 'String' to expected element type
+    // 'Array<ModelContent.Part>.ArrayLiteralElement'. Not sure if there's a way we can get it to
+    // work.
     let _ = try ModelContent(parts: [str, ModelContent.Part.data(
       mimetype: "foo",
       Data()
-    )] as [any PartsRepresentable])
+    )] as [any ThrowingPartsRepresentable])
     #if canImport(UIKit)
       _ = try ModelContent(role: "user", parts: UIImage())
       _ = try ModelContent(role: "user", parts: [UIImage()])
-      // Note: without `as [any PartsRepresentable]` this will fail to compile with "Cannot convert
-      // value of type `[Any]` to expected type `[any PartsRepresentable]`. Not sure if there's a
+      // Note: without `as [any ThrowingPartsRepresentable]` this will fail to compile with "Cannot
+      // convert
+      // value of type `[Any]` to expected type `[any ThrowingPartsRepresentable]`. Not sure if
+      // there's a
       // way we can get it to work.
-      _ = try ModelContent(parts: [str, UIImage()] as [any PartsRepresentable])
+      _ = try ModelContent(parts: [str, UIImage()] as [any ThrowingPartsRepresentable])
       // Alternatively, you can explicitly declare the type in a variable and pass it in.
-      let representable2: [any PartsRepresentable] = [str, UIImage()]
+      let representable2: [any ThrowingPartsRepresentable] = [str, UIImage()]
       _ = try ModelContent(parts: representable2)
       _ = try ModelContent(parts: [str, UIImage(),
-                                   ModelContent.Part.text(str)] as [any PartsRepresentable])
+                                   ModelContent.Part.text(str)] as [any ThrowingPartsRepresentable])
     #elseif canImport(AppKit)
       _ = try ModelContent(role: "user", parts: NSImage())
       _ = try ModelContent(role: "user", parts: [NSImage()])
-      // Note: without `as [any PartsRepresentable]` this will fail to compile with "Cannot convert
-      // value of type `[Any]` to expected type `[any PartsRepresentable]`. Not sure if there's a
+      // Note: without `as [any ThrowingPartsRepresentable]` this will fail to compile with "Cannot
+      // convert
+      // value of type `[Any]` to expected type `[any ThrowingPartsRepresentable]`. Not sure if
+      // there's a
       // way we can get it to work.
-      _ = try ModelContent(parts: [str, NSImage()] as [any PartsRepresentable])
+      _ = try ModelContent(parts: [str, NSImage()] as [any ThrowingPartsRepresentable])
       // Alternatively, you can explicitly declare the type in a variable and pass it in.
-      let representable2: [any PartsRepresentable] = [str, NSImage()]
+      let representable2: [any ThrowingPartsRepresentable] = [str, NSImage()]
       _ = try ModelContent(parts: representable2)
       _ =
         try ModelContent(parts: [str, NSImage(),
-                                 ModelContent.Part.text(str)] as [any PartsRepresentable])
+                                 ModelContent.Part.text(str)] as [any ThrowingPartsRepresentable])
     #endif
 
     // countTokens API
@@ -131,7 +138,7 @@ final class GoogleGenerativeAITests: XCTestCase {
 
     // Chat
     _ = genAI.startChat()
-    _ = try genAI.startChat(history: [ModelContent(parts: "abc")])
+    _ = genAI.startChat(history: [ModelContent(parts: "abc")])
   }
 
   // Result builder alternative
diff --git a/Tests/GoogleAITests/PartsRepresentableTests.swift b/Tests/GoogleAITests/PartsRepresentableTests.swift
index 5feb3f5..c0424d8 100644
--- a/Tests/GoogleAITests/PartsRepresentableTests.swift
+++ b/Tests/GoogleAITests/PartsRepresentableTests.swift
@@ -21,7 +21,7 @@ import XCTest
   import AppKit
 #endif
 
-final class PartsRepresentableTests: XCTestCase {
+final class ThrowingPartsRepresentableTests: XCTestCase {
   func testModelContentFromCGImageIsNotEmpty() throws {
     // adapted from https://forums.swift.org/t/creating-a-cgimage-from-color-array/18634/2
     var srgbArray = [UInt32](repeating: 0xFFFF_FFFF, count: 8 * 8)

From 5412c57a7329ba5c3068b48865ed21e8d6a78b9f Mon Sep 17 00:00:00 2001
From: Morgan Chen <morganchen12@gmail.com>
Date: Wed, 31 Jan 2024 15:31:09 -0800
Subject: [PATCH 10/15] api review feedback: use more specific error case and
 add failure tests

---
 Sources/GoogleAI/Chat.swift                   | 14 +++-
 Sources/GoogleAI/GenerateContentError.swift   |  3 +
 Sources/GoogleAI/GenerativeModel.swift        |  8 ++-
 .../GoogleAI/PartsRepresentable+Image.swift   |  6 +-
 .../PartsRepresentableTests.swift             | 66 +++++++++++++++++++
 5 files changed, 90 insertions(+), 7 deletions(-)

diff --git a/Sources/GoogleAI/Chat.swift b/Sources/GoogleAI/Chat.swift
index 1fc3a67..46ffe12 100644
--- a/Sources/GoogleAI/Chat.swift
+++ b/Sources/GoogleAI/Chat.swift
@@ -47,7 +47,11 @@ public class Chat {
     do {
       newContent = try content().map(populateContentRole(_:))
     } catch let underlying {
-      throw GenerateContentError.internalError(underlying: underlying)
+      if let contentError = underlying as? ImageConversionError {
+        throw GenerateContentError.promptContentError(underlying: contentError)
+      } else {
+        throw GenerateContentError.internalError(underlying: underlying)
+      }
     }
 
     // Send the history alongside the new message as context.
@@ -90,7 +94,13 @@ public class Chat {
       content = try contentClosure()
     } catch let underlying {
       return AsyncThrowingStream { continuation in
-        continuation.finish(throwing: GenerateContentError.internalError(underlying: underlying))
+        let error: Error
+        if let contentError = underlying as? ImageConversionError {
+          error = GenerateContentError.promptContentError(underlying: contentError)
+        } else {
+          error = GenerateContentError.internalError(underlying: underlying)
+        }
+        continuation.finish(throwing: error)
       }
     }
 
diff --git a/Sources/GoogleAI/GenerateContentError.swift b/Sources/GoogleAI/GenerateContentError.swift
index 38e6b92..75ddff8 100644
--- a/Sources/GoogleAI/GenerateContentError.swift
+++ b/Sources/GoogleAI/GenerateContentError.swift
@@ -16,6 +16,9 @@ import Foundation
 
 /// Errors that occur when generating content from a model.
 public enum GenerateContentError: Error {
+  /// An error occurred when constructing the prompt. Examine the related error for details.
+  case promptContentError(underlying: ImageConversionError)
+
   /// An internal error occurred. See the underlying error for more context.
   case internalError(underlying: Error)
 
diff --git a/Sources/GoogleAI/GenerativeModel.swift b/Sources/GoogleAI/GenerativeModel.swift
index d2c25bf..3c23586 100644
--- a/Sources/GoogleAI/GenerativeModel.swift
+++ b/Sources/GoogleAI/GenerativeModel.swift
@@ -159,7 +159,13 @@ public final class GenerativeModel {
       content = try contentClosure()
     } catch let underlying {
       return AsyncThrowingStream { continuation in
-        continuation.finish(throwing: GenerateContentError.internalError(underlying: underlying))
+        let error: Error
+        if let contentError = underlying as? ImageConversionError {
+          error = GenerateContentError.promptContentError(underlying: contentError)
+        } else {
+          error = GenerateContentError.internalError(underlying: underlying)
+        }
+        continuation.finish(throwing: error)
       }
     }
 
diff --git a/Sources/GoogleAI/PartsRepresentable+Image.swift b/Sources/GoogleAI/PartsRepresentable+Image.swift
index f9c699c..50f9c1f 100644
--- a/Sources/GoogleAI/PartsRepresentable+Image.swift
+++ b/Sources/GoogleAI/PartsRepresentable+Image.swift
@@ -25,10 +25,8 @@ private let imageCompressionQuality: CGFloat = 0.8
 /// For some image types like `CIImage`, creating valid model content requires creating a JPEG
 /// representation of the image that may not yet exist, which may be computationally expensive.
 public enum ImageConversionError: Error {
-  #if canImport(AppKit)
-    /// The image (the receiver of the call `toModelContentParts()`) was invalid.
-    case invalidUnderlyingImage
-  #endif
+  /// The image (the receiver of the call `toModelContentParts()`) was invalid.
+  case invalidUnderlyingImage
 
   /// A valid image destination could not be allocated.
   case couldNotAllocateDestination
diff --git a/Tests/GoogleAITests/PartsRepresentableTests.swift b/Tests/GoogleAITests/PartsRepresentableTests.swift
index c0424d8..24aef4a 100644
--- a/Tests/GoogleAITests/PartsRepresentableTests.swift
+++ b/Tests/GoogleAITests/PartsRepresentableTests.swift
@@ -14,6 +14,7 @@
 
 import CoreGraphics
 import CoreImage
+import GoogleGenerativeAI
 import XCTest
 #if canImport(UIKit)
   import UIKit
@@ -49,7 +50,51 @@ final class ThrowingPartsRepresentableTests: XCTestCase {
     XCTAssert(modelContent.count > 0, "Expected non-empty model content for CGImage: \(image)")
   }
 
+  func testModelContentFromInvalidCIImageThrows() throws {
+    let image = CIImage.empty()
+    do {
+      let _ = try image.tryPartsValue()
+    } catch {
+      guard let imageError = (error as? ImageConversionError) else {
+        XCTFail("Got unexpected error type: \(error)")
+        return
+      }
+      switch imageError {
+      case let .couldNotConvertToJPEG(source):
+        // String(describing:) works around a type error.
+        XCTAssertEqual(String(describing: source), String(describing: image))
+        return
+      case _:
+        XCTFail("Expected image conversion error, got \(imageError) instead")
+        return
+      }
+    }
+    XCTFail("Expected model content from invlaid image to error")
+  }
+
   #if canImport(UIKit)
+    func testModelContentFromInvalidUIImageThrows() throws {
+      let image = UIImage()
+      do {
+        _ = try image.tryPartsValue()
+      } catch {
+        guard let imageError = (error as? ImageConversionError) else {
+          XCTFail("Got unexpected error type: \(error)")
+          return
+        }
+        switch imageError {
+        case let .couldNotConvertToJPEG(source):
+          // String(describing:) works around a type error.
+          XCTAssertEqual(String(describing: source), String(describing: image))
+          return
+        case _:
+          XCTFail("Expected image conversion error, got \(imageError) instead")
+          return
+        }
+      }
+      XCTFail("Expected model content from invlaid image to error")
+    }
+
     func testModelContentFromUIImageIsNotEmpty() throws {
       let coreImage = CIImage(color: CIColor.red)
         .cropped(to: CGRect(origin: CGPointZero, size: CGSize(width: 16, height: 16)))
@@ -67,5 +112,26 @@ final class ThrowingPartsRepresentableTests: XCTestCase {
       let modelContent = try image.tryPartsValue()
       XCTAssert(modelContent.count > 0, "Expected non-empty model content for NSImage: \(image)")
     }
+
+    func testModelContentFromInvalidNSImageThrows() throws {
+      let image = NSImage()
+      do {
+        _ = try image.tryPartsValue()
+      } catch {
+        guard let imageError = (error as? ImageConversionError) else {
+          XCTFail("Got unexpected error type: \(error)")
+          return
+        }
+        switch imageError {
+        case .invalidUnderlyingImage:
+          // Pass
+          return
+        case _:
+          XCTFail("Expected image conversion error, got \(imageError) instead")
+          return
+        }
+      }
+      XCTFail("Expected model content from invlaid image to error")
+    }
   #endif
 }

From b744775fce82d424b9323939c496ba9a5ac5bed4 Mon Sep 17 00:00:00 2001
From: Morgan Chen <morganchen12@gmail.com>
Date: Thu, 15 Feb 2024 15:43:44 -0800
Subject: [PATCH 11/15] specialize error

---
 Sources/GoogleAI/Chat.swift                 | 4 ++--
 Sources/GoogleAI/GenerateContentError.swift | 2 +-
 Sources/GoogleAI/GenerativeModel.swift      | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/Sources/GoogleAI/Chat.swift b/Sources/GoogleAI/Chat.swift
index 46ffe12..1bce34f 100644
--- a/Sources/GoogleAI/Chat.swift
+++ b/Sources/GoogleAI/Chat.swift
@@ -48,7 +48,7 @@ public class Chat {
       newContent = try content().map(populateContentRole(_:))
     } catch let underlying {
       if let contentError = underlying as? ImageConversionError {
-        throw GenerateContentError.promptContentError(underlying: contentError)
+        throw GenerateContentError.promptImageContentError(underlying: contentError)
       } else {
         throw GenerateContentError.internalError(underlying: underlying)
       }
@@ -96,7 +96,7 @@ public class Chat {
       return AsyncThrowingStream { continuation in
         let error: Error
         if let contentError = underlying as? ImageConversionError {
-          error = GenerateContentError.promptContentError(underlying: contentError)
+          error = GenerateContentError.promptImageContentError(underlying: contentError)
         } else {
           error = GenerateContentError.internalError(underlying: underlying)
         }
diff --git a/Sources/GoogleAI/GenerateContentError.swift b/Sources/GoogleAI/GenerateContentError.swift
index 75ddff8..7f53aa6 100644
--- a/Sources/GoogleAI/GenerateContentError.swift
+++ b/Sources/GoogleAI/GenerateContentError.swift
@@ -17,7 +17,7 @@ import Foundation
 /// Errors that occur when generating content from a model.
 public enum GenerateContentError: Error {
   /// An error occurred when constructing the prompt. Examine the related error for details.
-  case promptContentError(underlying: ImageConversionError)
+  case promptImageContentError(underlying: ImageConversionError)
 
   /// An internal error occurred. See the underlying error for more context.
   case internalError(underlying: Error)
diff --git a/Sources/GoogleAI/GenerativeModel.swift b/Sources/GoogleAI/GenerativeModel.swift
index 3c23586..5d94621 100644
--- a/Sources/GoogleAI/GenerativeModel.swift
+++ b/Sources/GoogleAI/GenerativeModel.swift
@@ -161,7 +161,7 @@ public final class GenerativeModel {
       return AsyncThrowingStream { continuation in
         let error: Error
         if let contentError = underlying as? ImageConversionError {
-          error = GenerateContentError.promptContentError(underlying: contentError)
+          error = GenerateContentError.promptImageContentError(underlying: contentError)
         } else {
           error = GenerateContentError.internalError(underlying: underlying)
         }

From de4292882d6b98299cec067857a22c9c4a51375c Mon Sep 17 00:00:00 2001
From: Morgan Chen <morganchen12@gmail.com>
Date: Thu, 15 Feb 2024 16:37:55 -0800
Subject: [PATCH 12/15] style

---
 Tests/GoogleAITests/PartsRepresentableTests.swift | 1 -
 1 file changed, 1 deletion(-)

diff --git a/Tests/GoogleAITests/PartsRepresentableTests.swift b/Tests/GoogleAITests/PartsRepresentableTests.swift
index 0b3760f..da2f35f 100644
--- a/Tests/GoogleAITests/PartsRepresentableTests.swift
+++ b/Tests/GoogleAITests/PartsRepresentableTests.swift
@@ -24,7 +24,6 @@ import XCTest
 
 @available(iOS 15.0, macOS 11.0, macCatalyst 15.0, *)
 final class PartsRepresentableTests: XCTestCase {
-
   func testModelContentFromCGImageIsNotEmpty() throws {
     // adapted from https://forums.swift.org/t/creating-a-cgimage-from-color-array/18634/2
     var srgbArray = [UInt32](repeating: 0xFFFF_FFFF, count: 8 * 8)

From 0adb052a7a32dea8fd8db2b1338f3c39cb517c60 Mon Sep 17 00:00:00 2001
From: Morgan Chen <morganchen12@gmail.com>
Date: Tue, 20 Feb 2024 15:38:37 -0800
Subject: [PATCH 13/15] code feedback changes

---
 Sources/GoogleAI/Chat.swift            |  8 +++----
 Sources/GoogleAI/GenerativeModel.swift | 33 ++++++++++++++------------
 2 files changed, 22 insertions(+), 19 deletions(-)

diff --git a/Sources/GoogleAI/Chat.swift b/Sources/GoogleAI/Chat.swift
index d0c6fff..c7cfb85 100644
--- a/Sources/GoogleAI/Chat.swift
+++ b/Sources/GoogleAI/Chat.swift
@@ -88,11 +88,11 @@ public class Chat {
   /// - Parameter content: The new content to send as a single chat message.
   /// - Returns: A stream containing the model's response or an error if an error occurred.
   @available(macOS 12.0, *)
-  public func sendMessageStream(_ contentClosure: @autoclosure () throws -> [ModelContent])
+  public func sendMessageStream(_ content: @autoclosure () throws -> [ModelContent])
     -> AsyncThrowingStream<GenerateContentResponse, Error> {
-    let content: [ModelContent]
+    let resolvedContent: [ModelContent]
     do {
-      content = try contentClosure()
+      resolvedContent = try content()
     } catch let underlying {
       return AsyncThrowingStream { continuation in
         let error: Error
@@ -110,7 +110,7 @@ public class Chat {
         var aggregatedContent: [ModelContent] = []
 
         // Ensure that the new content has the role set.
-        let newContent: [ModelContent] = content.map(populateContentRole(_:))
+        let newContent: [ModelContent] = resolvedContent.map(populateContentRole(_:))
 
         // Send the history alongside the new message as context.
         let request = history + newContent
diff --git a/Sources/GoogleAI/GenerativeModel.swift b/Sources/GoogleAI/GenerativeModel.swift
index 2a95112..2a963f7 100644
--- a/Sources/GoogleAI/GenerativeModel.swift
+++ b/Sources/GoogleAI/GenerativeModel.swift
@@ -111,18 +111,21 @@ public final class GenerativeModel {
   /// - Parameter content: The input(s) given to the model as a prompt.
   /// - Returns: The generated content response from the model.
   /// - Throws: A ``GenerateContentError`` if the request failed.
-  public func generateContent(_ content: [ModelContent]) async throws
+  public func generateContent(_ content: @autoclosure () throws -> [ModelContent]) async throws
     -> GenerateContentResponse {
-    let generateContentRequest = GenerateContentRequest(model: modelResourceName,
-                                                        contents: content,
-                                                        generationConfig: generationConfig,
-                                                        safetySettings: safetySettings,
-                                                        isStreaming: false,
-                                                        options: requestOptions)
     let response: GenerateContentResponse
     do {
+      let generateContentRequest = try GenerateContentRequest(model: modelResourceName,
+                                                              contents: content(),
+                                                              generationConfig: generationConfig,
+                                                              safetySettings: safetySettings,
+                                                              isStreaming: false,
+                                                              options: requestOptions)
       response = try await generativeAIService.loadRequest(request: generateContentRequest)
     } catch {
+      if let imageError = error as? ImageConversionError {
+        throw GenerateContentError.promptImageContentError(underlying: imageError)
+      }
       throw GenerativeModel.generateContentError(from: error)
     }
 
@@ -251,16 +254,16 @@ public final class GenerativeModel {
   /// - Parameter content: The input given to the model as a prompt.
   /// - Returns: The results of running the model's tokenizer on the input; contains
   /// ``CountTokensResponse/totalTokens``.
-  /// - Throws: A ``CountTokensError`` if the tokenization request failed.
-  public func countTokens(_ content: [ModelContent]) async throws
+  /// - Throws: A ``CountTokensError`` if the tokenization request failed or the input content was
+  /// invalid.
+  public func countTokens(_ content: @autoclosure () throws -> [ModelContent]) async throws
     -> CountTokensResponse {
-    let countTokensRequest = CountTokensRequest(
-      model: modelResourceName,
-      contents: content,
-      options: requestOptions
-    )
-
     do {
+      let countTokensRequest = try CountTokensRequest(
+        model: modelResourceName,
+        contents: content(),
+        options: requestOptions
+      )
       return try await generativeAIService.loadRequest(request: countTokensRequest)
     } catch {
       throw CountTokensError.internalError(underlying: error)

From d962763ca1095879b54f2c12a9c0d3e708358aac Mon Sep 17 00:00:00 2001
From: Morgan Chen <morganchen12@gmail.com>
Date: Tue, 20 Feb 2024 15:45:15 -0800
Subject: [PATCH 14/15] use partsValue

---
 Sources/GoogleAI/ModelContent.swift       | 4 ++--
 Sources/GoogleAI/PartsRepresentable.swift | 6 +++---
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/Sources/GoogleAI/ModelContent.swift b/Sources/GoogleAI/ModelContent.swift
index edfead4..172fc80 100644
--- a/Sources/GoogleAI/ModelContent.swift
+++ b/Sources/GoogleAI/ModelContent.swift
@@ -114,7 +114,7 @@ public struct ModelContent: Codable, Equatable {
   /// ``Part``. See ``ThrowingPartsRepresentable`` for types that can be interpreted as `Part`s.
   public init(role: String? = "user", parts: some PartsRepresentable) {
     self.role = role
-    self.parts = parts.toPartsValue()
+    self.parts = parts.partsValue
   }
 
   /// Creates a new value from a list of ``Part``s.
@@ -135,7 +135,7 @@ public struct ModelContent: Codable, Equatable {
   /// ``ThrowingPartsRepresentable``
   /// for types that can be interpreted as `Part`s.
   public init(role: String? = "user", _ parts: [PartsRepresentable]) {
-    let content = parts.flatMap { $0.toPartsValue() }
+    let content = parts.flatMap { $0.partsValue }
     self.init(role: role, parts: content)
   }
 }
diff --git a/Sources/GoogleAI/PartsRepresentable.swift b/Sources/GoogleAI/PartsRepresentable.swift
index 5d281ef..05ba0d9 100644
--- a/Sources/GoogleAI/PartsRepresentable.swift
+++ b/Sources/GoogleAI/PartsRepresentable.swift
@@ -26,13 +26,13 @@ public protocol ThrowingPartsRepresentable {
 /// ``ThrowingPartsRepresentable``
 @available(iOS 15.0, macOS 11.0, macCatalyst 15.0, *)
 public protocol PartsRepresentable: ThrowingPartsRepresentable {
-  func toPartsValue() -> [ModelContent.Part]
+  var partsValue: [ModelContent.Part] { get }
 }
 
 @available(iOS 15.0, macOS 11.0, macCatalyst 15.0, *)
 public extension PartsRepresentable {
   func tryPartsValue() throws -> [ModelContent.Part] {
-    return toPartsValue()
+    return partsValue
   }
 }
 
@@ -60,7 +60,7 @@ extension [ThrowingPartsRepresentable]: ThrowingPartsRepresentable {
 /// Enables a `String` to be passed in as ``ThrowingPartsRepresentable``.
 @available(iOS 15.0, macOS 11.0, macCatalyst 15.0, *)
 extension String: PartsRepresentable {
-  public func toPartsValue() -> [ModelContent.Part] {
+  public var partsValue: [ModelContent.Part] {
     return [.text(self)]
   }
 }

From 183f14ede5c13441be36885c212b03dbfcdd74a1 Mon Sep 17 00:00:00 2001
From: Morgan Chen <morganchen12@gmail.com>
Date: Wed, 21 Feb 2024 13:43:08 -0800
Subject: [PATCH 15/15] use consistent closure name

---
 Sources/GoogleAI/GenerativeModel.swift | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/Sources/GoogleAI/GenerativeModel.swift b/Sources/GoogleAI/GenerativeModel.swift
index 2a963f7..03e0191 100644
--- a/Sources/GoogleAI/GenerativeModel.swift
+++ b/Sources/GoogleAI/GenerativeModel.swift
@@ -169,11 +169,11 @@ public final class GenerativeModel {
   /// - Returns: A stream wrapping content generated by the model or a ``GenerateContentError``
   ///     error if an error occurred.
   @available(macOS 12.0, *)
-  public func generateContentStream(_ contentClosure: @autoclosure () throws -> [ModelContent])
+  public func generateContentStream(_ content: @autoclosure () throws -> [ModelContent])
     -> AsyncThrowingStream<GenerateContentResponse, Error> {
-    let content: [ModelContent]
+    let evaluatedContent: [ModelContent]
     do {
-      content = try contentClosure()
+      evaluatedContent = try content()
     } catch let underlying {
       return AsyncThrowingStream { continuation in
         let error: Error
@@ -187,7 +187,7 @@ public final class GenerativeModel {
     }
 
     let generateContentRequest = GenerateContentRequest(model: modelResourceName,
-                                                        contents: content,
+                                                        contents: evaluatedContent,
                                                         generationConfig: generationConfig,
                                                         safetySettings: safetySettings,
                                                         isStreaming: true,