tools/SwiftSyntax/SyntaxNodes.swift.gyb

%{
  # -*- mode: Swift -*-
  from gyb_syntax_support import *
  NODE_MAP = create_node_map()
  # Ignore the following admonition it applies to the resulting .swift file only
}%
//// Automatically Generated From SyntaxNodes.swift.gyb.
//// Do Not Edit Directly!
//===------------ SyntaxNodes.swift - Syntax Node definitions -------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 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
//
//===----------------------------------------------------------------------===//

%{
"""
Each Syntax node is a subclass of a more generic node. For example,
StructDeclSyntax is a subclass of DeclSyntax and can be used in contexts
where DeclSyntax is expected.

Each node will have:
- An accessor for each child that will lazily instantiate it.
- A `withX(_ x: XSyntax)` method for each child that will return a new Syntax
  node with the existing X child replaced with the passed-in version. This is a
  way to incrementally transform nodes in the tree.
- An `addX(_ x: XSyntax)` method for children that are collections. This will
  append the provided node to the collection and return a new node with that
  collection replaced.
- (in DEBUG mode) a `validate()` method that's called in the initializer. This
  only validates that all the children are the right kind/token, and does not
  raise an error if, say, a non-optional child is missing.
"""
}%

% for node in SYNTAX_NODES:
%   base_type = node.base_type
%   if node.collection_element:
public typealias ${node.name} = SyntaxCollection<${node.collection_element_type}>
%   else:
public class ${node.name}: ${base_type} {
%     if node.children:
  enum Cursor: Int {
%     for child in node.children:
    case ${child.swift_name}
%     end
  }
%     end

%     if node.requires_validation():
#if DEBUG
  override func validate() {
      if isMissing { return }
    precondition(raw.layout.count == ${len(node.children)})
%       for child in node.children:
%         child_var = '_' + child.swift_name
    let ${child_var} = raw[Cursor.${child.swift_syntax_kind}]
%         if child.token_choices:
%           choices = ["." + choice.swift_kind() for choice in child.token_choices]
%           choice_array = "[%s]" % ', '.join(choices)
    guard let ${child_var}TokenKind = ${child_var}.tokenKind else {
      fatalError("expected token child, got \(${child_var}.kind)")
    }
    precondition(${choice_array}.contains(${child_var}TokenKind),
      "expected one of ${choice_array} for '${child.swift_name}' " + 
      "in node of kind ${node.swift_syntax_kind}")
%         elif child.text_choices:
%           choices = ", ".join("\"%s\"" % choice
%                               for choice in child.text_choices)
    guard let ${child_var}TokenKind = ${child_var}.tokenKind else {
      fatalError("expected token child, got \(${child_var}.kind)")
    }
    precondition([${choices}].contains(${child_var}TokenKind.text),
                 "expected one of '[${', '.join(child.text_choices)}]', got " +
                 "'\(${child_var}TokenKind.text)'")
%         else:
    precondition(${child_var}.kind == .${child.swift_syntax_kind},
                 "expected child of kind .${child.swift_syntax_kind}, " +
                 "got \(${child_var}.kind)")
%         end
%       end
  }
#endif
%     end
%     for child in node.children:

%       if child.is_optional:
  public var ${child.swift_name}: ${child.type_name}? {
    guard raw[Cursor.${child.swift_name}].isPresent else { return nil }
    return ${child.type_name}(root: _root,
      data: data.cachedChild(at: Cursor.${child.swift_name}))
  }
%       else:
  public var ${(child.swift_name)}: ${child.type_name} {
    return ${child.type_name}(root: _root,
      data: data.cachedChild(at: Cursor.${child.swift_name}))
  }
%       end
%       child_node = NODE_MAP.get(child.syntax_kind)
%       if child_node and child_node.is_syntax_collection():
%         child_elt = child_node.collection_element_name
%         child_elt_type = child_node.collection_element_type

  public func add${child_elt}(_ elt: ${child_elt_type}) -> ${node.name} {
    let childRaw = raw[Cursor.${child.swift_name}].appending(elt.raw)
    let (root, newData) = data.replacingChild(childRaw,
                                              at: Cursor.${child.swift_name})
    return ${node.name}(root: root, data: newData)
  }
%       end

  public func with${child.name}(
    _ new${child.type_name}: ${child.type_name}?) -> ${node.name} {
    let raw = new${child.type_name}?.raw ?? ${make_missing_swift_child(child)}
    let (root, newData) = data.replacingChild(raw,
                                              at: Cursor.${child.swift_name})
    return ${node.name}(root: root, data: newData)
  }
%     end
}
%   end
% end

/// MARK: Convenience methods

extension StructDeclSyntax {
  func withIdentifier(_ name: String) -> StructDeclSyntax {
    let newToken = SyntaxFactory.makeIdentifier(name,
      leadingTrivia: identifier.leadingTrivia,
      trailingTrivia: identifier.trailingTrivia)
    return withIdentifier(newToken)
  }
}