add static function

Author: dankinsoid

Sources/VDFlow/StepsCollection.swift

@@ -22,14 +22,19 @@ public protocol StepsCollection {
 	///
 	/// This type is typically an enum generated by the `@Steps` macro.
 	associatedtype AllSteps: Hashable & Codable & Sendable
+
 	/// The currently selected step in the collection.
 	///
 	/// Setting this property navigates to the selected step.
 	var selected: AllSteps { get set }
+
 	/// The ID of the last mutation made to this collection.
 	///
 	/// This property is used internally for tracking changes to the navigation state.
 	var _lastMutateID: MutateID? { get }
+
+	/// Retrieves the step ID for a specific step key path.
+	static func step<T>(for keyPath: WritableKeyPath<Self, StepID<T>>) -> AllSteps?
 }
 
 extension StepsCollection {

Sources/VDFlowMacros/StepsMacro.swift

@@ -403,6 +403,17 @@ public struct StepsMacro: MemberAttributeMacro, ExtensionMacro, MemberMacro, Acc
 			funcString += "}"
 			return DeclSyntax(stringLiteral: funcString)
 		}
+		let stepFunc: DeclSyntax =
+			   """
+			   public static func step<T>(for keyPath: WritableKeyPath<Self, StepID<T>>) -> AllSteps? {
+			     switch keyPath {
+			     \(raw: cases.map { "case \\.$\($0), \\._\($0): return .\($0)" }.joined(separator: "\n"))
+			     default:
+			      return nil
+			     }
+			   }
+			   """
+		result.append(stepFunc)
 		return result
 	}
 }