Added dynamic member lookup for embeded structs

Author: wickwirew

Sources/Compiler/Gen/SwiftLanguage.swift

@@ -202,7 +202,7 @@ public struct SwiftLanguage: Language {
 
         return DeclSyntax(variable)
     }
-
+    
     /// Generates the expression to initialize the query.
     ///
     /// ```swift
@@ -416,7 +416,7 @@ public struct SwiftLanguage: Language {
             """
         }
     }
-
+    
     private static func declaration(
         for model: GeneratedModel,
         isOutput: Bool,
@@ -435,7 +435,20 @@ public struct SwiftLanguage: Language {
             }
         }
 
+        let dynamicLookupTables = model.fields.values.compactMap { value -> (String, GeneratedModel)? in
+            guard case let .model(model) = value.type else { return nil }
+            return (value.name, model)
+        }
+        
+        let addDynamicLookup = isOutput && !dynamicLookupTables.isEmpty && model.fields.count > 1
+        
         let strct = StructDeclSyntax(
+            attributes: AttributeListSyntax {
+                if addDynamicLookup {
+                    let attr: AttributeSyntax = "@dynamicMemberLookup"
+                    attr.with(\.trailingTrivia, .newline)
+                }
+            },
             name: TokenSyntax.identifier(model.name),
             inheritanceClause: inheretance
         ) {
@@ -447,11 +460,54 @@ public struct SwiftLanguage: Language {
                 rowDecodableInit(for: model)
                 memberwiseInit(for: model)
             }
+            
+            if addDynamicLookup {
+                for (fieldName, table) in dynamicLookupTables {
+                    dynamicMemberLookup(fieldName: fieldName, typeName: table.name)
+                }
+            }
         }
 
         return DeclSyntax(strct)
     }
 
+    private static func dynamicMemberLookup(
+        fieldName: String,
+        typeName: String
+    ) -> SubscriptDeclSyntax {
+        return SubscriptDeclSyntax(
+            subscriptKeyword: TokenSyntax.keyword(.subscript)
+                .with(\.trailingTrivia, .spaces(0)),
+            genericParameterClause: GenericParameterClauseSyntax {
+                GenericParameterSyntax(name: "Value")
+            },
+            parameterClause: FunctionParameterClauseSyntax(
+                parameters: [
+                    FunctionParameterSyntax(
+                        firstName: "dynamicMember",
+                        secondName: "dynamicMember",
+                        type: IdentifierTypeSyntax(name: "KeyPath<\(raw: typeName), Value>"),
+                        trailingComma: nil
+                    )
+                ]
+            ),
+            returnClause: ReturnClauseSyntax(type: IdentifierTypeSyntax(name: "Value")),
+            accessorBlock: AccessorBlockSyntax(accessors: .getter(CodeBlockItemListSyntax {
+                SubscriptCallExprSyntax(
+                    calledExpression: DeclReferenceExprSyntax(baseName: TokenSyntax.identifier(fieldName)),
+                    arguments: LabeledExprListSyntax {
+                        LabeledExprSyntax(
+                            label: "keyPath",
+                            colon: TokenSyntax.colonToken(),
+                            expression: DeclReferenceExprSyntax(baseName: "dynamicMember"),
+                            trailingComma: nil
+                        )
+                    }
+                )
+            }))
+        )
+    }
+    
     private static func rowDecodableInit(
         for model: GeneratedModel
     ) -> InitializerDeclSyntax {

Sources/Compiler/Project.swift

@@ -7,6 +7,7 @@
 
 import Foundation
 
+/// Small object to make interacting with the overall project structure easier.
 public struct Project {
     public let url: URL
     public let migrationsDirectory: URL
@@ -24,6 +25,10 @@ public struct Project {
         self.queriesDirectory = url.appendingPathComponent("Queries")
     }
 
+    public static func inWorkingDir() -> Project {
+        Project(url: URL(fileURLWithPath: FileManager.default.currentDirectoryPath))
+    }
+    
     public var doesMigrationsExist: Bool {
         fileSystem.exists(at: migrationsDirectory)
     }

Sources/FeatherCLI/InitCommand.swift

@@ -13,7 +13,7 @@ struct InitCommand: ParsableCommand {
     static let configuration = CommandConfiguration(commandName: "init")
 
     func run() throws {
-        let project = Project(url: URL(fileURLWithPath: FileManager.default.currentDirectoryPath))
+        let project = Project.inWorkingDir()
         try project.setup()
         try project.addMigration()
     }

Sources/FeatherCLI/MigrateCommand.swift

@@ -19,7 +19,7 @@ struct MigrateCommand: ParsableCommand {
         static let configuration = CommandConfiguration(commandName: "add")
 
         func run() throws {
-            let project = Project(url: URL(fileURLWithPath: FileManager.default.currentDirectoryPath))
+            let project = Project.inWorkingDir()
 
             guard project.doesMigrationsExist else {
                 throw FeatherError.sourcesNotFound

Sources/FeatherCLI/QueriesCommand.swift

@@ -21,7 +21,7 @@ struct QueriesCommand: ParsableCommand {
         @Argument var name: String
 
         func run() throws {
-            let project = Project(url: URL(fileURLWithPath: FileManager.default.currentDirectoryPath))
+            let project = Project.inWorkingDir()
 
             guard project.doesQueriesExist else {
                 throw FeatherError.sourcesNotFound