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//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2023 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
//
//===----------------------------------------------------------------------===//
extension Syntax {
/// Implementation of 'SyntaxProtocol.previousToken(viewMode:)'
func previousToken(viewMode: SyntaxTreeViewMode) -> TokenSyntax? {
guard let parentDataRef = data.parent else {
return nil
}
for case let childDataRef? in arena.layout(for: parentDataRef)[..<layoutIndexInParent].reversed() {
if let token = Syntax(arena: arena, dataRef: childDataRef).lastToken(viewMode: viewMode) {
return token
}
}
return Syntax(arena: arena, dataRef: parentDataRef).previousToken(viewMode: viewMode)
}
/// Implementation of 'SyntaxProtocol.nextToken(viewMode:)'
func nextToken(viewMode: SyntaxTreeViewMode) -> TokenSyntax? {
guard let parentDataRef = data.parent else {
return nil
}
for case let childDataRef? in arena.layout(for: parentDataRef)[(layoutIndexInParent &+ 1)...] {
if let token = Syntax(arena: arena, dataRef: childDataRef).firstToken(viewMode: viewMode) {
return token
}
}
return Syntax(arena: arena, dataRef: parentDataRef).nextToken(viewMode: viewMode)
}
/// Implementation of 'SyntaxProtocol.firstToken(viewMode:)'
///
/// - Note: Can't use 'RawSyntax.firstToken(viewMode:)' because it loses absolute info.
func firstToken(viewMode: SyntaxTreeViewMode) -> TokenSyntax? {
guard viewMode.shouldTraverse(node: raw) else {
return nil
}
if raw.isToken {
return TokenSyntax(self)!
}
for case let childDataRef? in layoutBuffer {
if let token = Syntax(arena: arena, dataRef: childDataRef).firstToken(viewMode: viewMode) {
return token
}
}
return nil
}
/// Implementation of 'SyntaxProtocol.lastToken(viewMode:)'
///
/// - Note: Can't use 'RawSyntax.lastToken(viewMode:)' because it loses absolute info.
func lastToken(viewMode: SyntaxTreeViewMode) -> TokenSyntax? {
guard viewMode.shouldTraverse(node: raw) else {
return nil
}
if raw.isToken {
return TokenSyntax(self)!
}
for case let childDataRef? in layoutBuffer.reversed() {
if let token = Syntax(arena: arena, dataRef: childDataRef).lastToken(viewMode: viewMode) {
return token
}
}
return nil
}
}
/// Sequence of tokens that are part of the provided Syntax node.
public struct TokenSequence: Sequence, Sendable {
/// Iterates over a ``TokenSequence``.
public struct Iterator: IteratorProtocol {
var nextToken: TokenSyntax?
/// The last token to iterate (inclusive).
let endToken: TokenSyntax?
let viewMode: SyntaxTreeViewMode
init(_ token: TokenSyntax?, endToken: TokenSyntax?, viewMode: SyntaxTreeViewMode) {
self.nextToken = token
self.endToken = endToken
self.viewMode = viewMode
}
/// Return the next element in a ``TokenSequence``.
public mutating func next() -> TokenSyntax? {
guard let token = self.nextToken else { return nil }
if nextToken == endToken {
self.nextToken = nil
} else {
self.nextToken = token.nextToken(viewMode: viewMode)
}
return token
}
}
let node: Syntax
let viewMode: SyntaxTreeViewMode
/// Construct a ``TokenSequence`` that walks all tokens in `node` in source order,
/// recursively walking into child nodes.
///
/// All nodes that are not visible in the given `viewMode` are skipped.
public init(_ node: Syntax, viewMode: SyntaxTreeViewMode) {
self.node = node
self.viewMode = viewMode
}
/// Create an iterator that iterates over all the tokens in the sequence.
public func makeIterator() -> Iterator {
return Iterator(
node.firstToken(viewMode: viewMode),
endToken: node.lastToken(viewMode: viewMode),
viewMode: viewMode
)
}
/// Iterate the tokens in reverse order.
public func reversed() -> ReversedTokenSequence {
return ReversedTokenSequence(node, viewMode: viewMode)
}
}
extension TokenSequence: CustomReflectable {
/// A custom mirror for ``TokenSequence`` that shows all elements in the sequence.
public var customMirror: Mirror {
return Mirror(self, unlabeledChildren: self.map { $0 })
}
}
/// Reverse sequence of tokens that are part of the provided Syntax node.
public struct ReversedTokenSequence: Sequence, Sendable {
/// Iterates over a ``ReversedTokenSequence``.
public struct Iterator: IteratorProtocol {
var nextToken: TokenSyntax?
let startPosition: AbsolutePosition
let viewMode: SyntaxTreeViewMode
init(_ token: TokenSyntax?, startPosition: AbsolutePosition, viewMode: SyntaxTreeViewMode) {
self.nextToken = token
self.startPosition = startPosition
self.viewMode = viewMode
}
/// Returns the next element in a ``ReversedTokenSequence``, i.e. the one
/// that occurred before the current token in source order.
public mutating func next() -> TokenSyntax? {
guard let token = self.nextToken else { return nil }
self.nextToken = token.previousToken(viewMode: viewMode)
// Make sure we stop once we went beyond the start of the containing node.
if let nextTok = self.nextToken, nextTok.position < self.startPosition {
self.nextToken = nil
}
return token
}
}
let node: Syntax
let viewMode: SyntaxTreeViewMode
/// Construct a ``TokenSequence`` that walks all tokens in `node` in reverse
/// source order, recursively walking into child nodes.
///
/// All nodes that are not visible in the given `viewMode` are skipped.
public init(_ node: Syntax, viewMode: SyntaxTreeViewMode) {
self.node = node
self.viewMode = viewMode
}
/// Create an iterator that iterates over all the tokens in the sequence.
public func makeIterator() -> Iterator {
return Iterator(node.lastToken(viewMode: viewMode), startPosition: node.position, viewMode: viewMode)
}
/// Iterate over the tokens in source order.
public func reversed() -> TokenSequence {
return TokenSequence(node, viewMode: viewMode)
}
}
extension ReversedTokenSequence: CustomReflectable {
/// A custom mirror for ``ReversedTokenSequence`` that shows all elements in the sequence.
public var customMirror: Mirror {
return Mirror(self, unlabeledChildren: self.map { $0 })
}
}
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