Add result builder to decl blocks

Author: kimdv

Sources/SwiftSyntaxBuilder/Buildables.swift.gyb

@@ -41,6 +41,8 @@ public protocol ${kind}ListBuildable: SyntaxListBuildable {
 
 %     if kind == 'Syntax':
 public protocol ${kind}Buildable: ${kind}ListBuildable {
+%     elif kind == 'Decl':
+public protocol ${kind}Buildable: SyntaxBuildable, ${kind}ListBuildable, ExpressibleAsMemberDeclListItem, ExpressibleAsCodeBlockItem {
 %     else:
 public protocol ${kind}Buildable: SyntaxBuildable, ${kind}ListBuildable {
 %     end
@@ -82,6 +84,20 @@ extension ${kind}Buildable {
     [build${kind}(format: format, leadingTrivia: leadingTrivia)]
   }
 }
+%     if kind == 'Decl':
+
+extension DeclBuildable {
+  public func createMemberDeclListItem() -> MemberDeclListItem { 
+    MemberDeclListItem(decl: self)
+  }
+}
+
+extension DeclBuildable {
+  public func createCodeBlockItem() -> CodeBlockItem { 
+    CodeBlockItem(item: self)
+  }
+}
+%     end
 
 %   end
 % end

Sources/SwiftSyntaxBuilder/ExpressibleBuildables.swift.gyb

@@ -0,0 +1,64 @@
+%{
+  from gyb_syntax_support import *
+  from gyb_syntax_support.kinds import SYNTAX_BASE_KINDS, lowercase_first_word, syntax_buildable_child_type
+  NODE_MAP = create_node_map()
+  # -*- mode: Swift -*-
+  # Ignore the following admonition it applies to the resulting .swift file only
+}%
+//// Automatically Generated From ResultBuilders.swift.gyb.
+//// Do Not Edit Directly!
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2021 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import SwiftSyntax
+
+public protocol ExpressibleAsSyntaxBuildable {
+  func createSyntaxBuildable() -> SyntaxBuildable
+}
+
+public protocol ExpressibleAsTokenSyntax {
+  func createTokenSyntax() -> TokenSyntax
+}
+
+% for node in SYNTAX_NODES:
+%   if node.is_syntax_collection():
+%     # child_node = NODE_MAP.get(child.syntax_kind)
+%     element_type = syntax_buildable_child_type(node.collection_element_type, node.collection_element, node.is_token())
+%     # `SyntaxBuildable` and `TokenSyntax` are used multiple places
+%     # so we add them manually af the buttom
+%     if element_type not in ['SyntaxBuildable', 'TokenSyntax', 'Expr']:
+public protocol ExpressibleAs${element_type} {
+  func create${element_type}() -> ${element_type}
+}
+%       if element_type not in ['ExprBuildable']:
+
+extension ${element_type}: ExpressibleAs${element_type} {
+  public func create${element_type}() -> ${element_type} { 
+    self
+  }
+}
+%       end
+%     end
+%   end
+% end
+% for node in SYNTAX_NODES:
+%   if node.is_buildable() and not node.is_syntax_collection() and node.base_kind not in ['Stmt', 'Type']:
+%     if node.base_kind not in ['Syntax', 'Pattern', 'Decl', 'Expr']:
+
+extension ${node.syntax_kind}: ExpressibleAs${node.syntax_kind} {
+  public func create${node.syntax_kind}() -> ${node.syntax_kind} {
+    ${node.syntax_kind}(decl: self)
+  }
+}
+%     end
+%   end
+% end

Sources/SwiftSyntaxBuilder/ResultBuilders.swift.gyb

@@ -29,11 +29,11 @@ public struct ${node.syntax_kind}Builder {
 
   /// The type of individual statement expressions in the transformed function,
   /// which defaults to Component if buildExpression() is not provided.
-  public typealias Expression = ${element_type}
+  public typealias Expression = ExpressibleAs${element_type}
 
   /// The type of a partial result, which will be carried through all of the
   /// build methods.
-  public typealias Component = [${element_type}]
+  public typealias Component = [ExpressibleAs${element_type}]
 
   /// The type of the final returned result, which defaults to Component if
   /// buildFinalResult() is not provided.
@@ -84,7 +84,7 @@ public struct ${node.syntax_kind}Builder {
   /// If declared, this will be called on the partial result from the outermost
   /// block statement to produce the final returned result.
   public static func buildFinalResult(_ component: Component) -> FinalResult {
-    .init(component)
+    .init(component.map { $0.create${element_type}() })
   }
 }
 

Sources/SwiftSyntaxBuilder/gyb_generated/Buildables.swift

@@ -24,7 +24,7 @@ public protocol DeclListBuildable: SyntaxListBuildable {
   func buildDeclList(format: Format, leadingTrivia: Trivia?) -> [DeclSyntax]
 }
 
-public protocol DeclBuildable: SyntaxBuildable, DeclListBuildable {
+public protocol DeclBuildable: SyntaxBuildable, DeclListBuildable, ExpressibleAsMemberDeclListItem, ExpressibleAsCodeBlockItem {
   /// Builds a `DeclSyntax`.
   /// - Parameter format: The `Format` to use.
   /// - Parameter leadingTrivia: Replaces the the last leading trivia if not nil.
@@ -62,6 +62,18 @@ extension DeclBuildable {
   }
 }
 
+extension DeclBuildable {
+  public func createMemberDeclListItem() -> MemberDeclListItem { 
+    MemberDeclListItem(decl: self)
+  }
+}
+
+extension DeclBuildable {
+  public func createCodeBlockItem() -> CodeBlockItem { 
+    CodeBlockItem(item: self)
+  }
+}
+
 public protocol ExprListBuildable: SyntaxListBuildable {
   /// Builds list of `ExprSyntax`s.
   /// - Parameter format: The `Format` to use.