[Vertex AI] Refactor Schema declarations (#13616)

Author: andrewheard

FirebaseVertexAI/CHANGELOG.md

@@ -11,6 +11,13 @@
   renamed to `inlineData`; no functionality changes. (#13700)
 - [changed] **Breaking Change**: The property `citationSources` of
   `CitationMetadata` has been renamed to `citations`. (#13702)
+- [changed] **Breaking Change**: The constructor for `Schema` is now deprecated;
+  use the new static methods `Schema.string(...)`, `Schema.object(...)`, etc.,
+  instead. (#13616)
+- [changed] **Breaking Change**: The constructor for `FunctionDeclaration` now
+  accepts an array of *optional* parameters instead of a list of *required*
+  parameters; if a parameter is not listed as optional it is assumed to be
+  required. (#13616)
 
 # 11.3.0
 - [added] Added `Decodable` conformance for `FunctionResponse`. (#13606)

FirebaseVertexAI/Sample/FunctionCallingSample/ViewModels/FunctionCallingViewModel.swift

@@ -45,20 +45,15 @@ class FunctionCallingViewModel: ObservableObject {
           name: "get_exchange_rate",
           description: "Get the exchange rate for currencies between countries",
           parameters: [
-            "currency_from": Schema(
-              type: .string,
-              format: "enum",
-              description: "The currency to convert from in ISO 4217 format",
-              enumValues: ["USD", "EUR", "JPY", "GBP", "AUD", "CAD"]
+            "currency_from": .enumeration(
+              values: ["USD", "EUR", "JPY", "GBP", "AUD", "CAD"],
+              description: "The currency to convert from in ISO 4217 format"
             ),
-            "currency_to": Schema(
-              type: .string,
-              format: "enum",
-              description: "The currency to convert to in ISO 4217 format",
-              enumValues: ["USD", "EUR", "JPY", "GBP", "AUD", "CAD"]
+            "currency_to": .enumeration(
+              values: ["USD", "EUR", "JPY", "GBP", "AUD", "CAD"],
+              description: "The currency to convert to in ISO 4217 format"
             ),
-          ],
-          requiredParameters: ["currency_from", "currency_to"]
+          ]
         ),
       ])]
     )

FirebaseVertexAI/Sources/FunctionCalling.swift

@@ -43,17 +43,15 @@ public struct FunctionDeclaration {
   ///   - name: The name of the function; must be a-z, A-Z, 0-9, or contain underscores and dashes,
   ///   with a maximum length of 63.
   ///   - description: A brief description of the function.
-  ///   - parameters: Describes the parameters to this function; the keys are parameter names and
-  ///   the values are ``Schema`` objects describing them.
-  ///   - requiredParameters: A list of required parameters by name.
-  public init(name: String, description: String, parameters: [String: Schema]?,
-              requiredParameters: [String]? = nil) {
+  ///   - parameters: Describes the parameters to this function.
+  public init(name: String, description: String, parameters: [String: Schema],
+              optionalParameters: [String] = []) {
     self.name = name
     self.description = description
-    self.parameters = Schema(
-      type: .object,
+    self.parameters = Schema.object(
       properties: parameters,
-      requiredProperties: requiredParameters
+      optionalProperties: optionalParameters,
+      nullable: false
     )
   }
 }