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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
//
//===----------------------------------------------------------------------===//
import SwiftSyntax
import SwiftSyntaxBuilder
import SyntaxSupport
/// Something that can either be a node of the given kind or a token of the
/// given token kind.
public enum SyntaxOrTokenNodeKind: Hashable {
case node(kind: SyntaxNodeKind)
case token(Token)
}
/// Extension to the ``Child`` type to provide functionality specific to
/// SwiftSyntaxBuilder.
extension Child {
/// The type of this child, represented by a ``SyntaxBuildableType``, which can
/// be used to create the corresponding `Buildable` and `ExpressibleAs` types.
public var buildableType: SyntaxBuildableType {
let buildableKind: SyntaxOrTokenNodeKind
switch kind {
case .node(kind: let kind):
buildableKind = .node(kind: kind)
case .nodeChoices:
buildableKind = .node(kind: .syntax)
case .collection(kind: let kind, _, _, _):
buildableKind = .node(kind: kind)
case .token:
buildableKind = .token(self.tokenKind!)
}
return SyntaxBuildableType(
kind: buildableKind,
isOptional: isOptional
)
}
public var parameterBaseType: TypeSyntax {
switch kind {
case .nodeChoices:
return self.syntaxChoicesType
default:
return buildableType.parameterBaseType
}
}
public var parameterType: TypeSyntax {
return self.buildableType.optionalWrapped(type: parameterBaseType)
}
public var defaultValue: ExprSyntax? {
if isOptional || isUnexpectedNodes {
if buildableType.isBaseType && kind.isNodeChoicesEmpty {
return ExprSyntax("\(buildableType.buildable).none")
} else {
return ExprSyntax("nil")
}
}
if case .collection(_, _, defaultsToEmpty: true, _) = kind {
return ExprSyntax("[]")
}
guard let token = token, isToken else {
return buildableType.defaultValue
}
if token.text != nil {
return ExprSyntax(".\(token.varOrCaseName)Token()")
}
if case .token(let choices, _, _) = kind,
case .keyword(let keyword) = choices.only
{
return ExprSyntax(".\(token.varOrCaseName)(.\(keyword.spec.varOrCaseName))")
}
return nil
}
/// If the child node has a default value, return an expression of the form
/// ` = default_value` that can be used as the default value to for a
/// function parameter. Otherwise, return `nil`.
public var defaultInitialization: InitializerClauseSyntax? {
if let defaultValue {
return InitializerClauseSyntax(
equal: .equalToken(leadingTrivia: .space, trailingTrivia: .space),
value: defaultValue
)
} else {
return nil
}
}
/// If this node is a token that can't contain arbitrary text, generate a Swift
/// `precondition` statement that verifies the variable with name var_name and of type
/// ``TokenSyntax`` contains one of the supported text options. Otherwise return `nil`.
public func generateAssertStmtTextChoices(varName: String) -> FunctionCallExprSyntax? {
guard case .token(choices: let choices, requiresLeadingSpace: _, requiresTrailingSpace: _) = kind else {
return nil
}
let tokenCanContainArbitraryText = choices.contains {
switch $0 {
case .token(let token):
return token.spec.text == nil
case .keyword:
return false
}
}
let choicesTexts: [String]
if tokenCanContainArbitraryText {
// Don't generate a precondition statement if token can contain arbitrary text.
return nil
} else if !choices.isEmpty {
choicesTexts = choices.compactMap {
switch $0 {
case .token(let token):
return token.spec.text
case .keyword(let keyword):
return keyword.spec.name
}
}
} else {
return nil
}
var preconditionChoices: [ExprSyntax] = []
if buildableType.isOptional {
preconditionChoices.append(
ExprSyntax(
SequenceExprSyntax {
DeclReferenceExprSyntax(baseName: .identifier(varName))
BinaryOperatorExprSyntax(text: "==")
NilLiteralExprSyntax()
}
)
)
}
for textChoice in choicesTexts {
preconditionChoices.append(
ExprSyntax(
SequenceExprSyntax {
MemberAccessExprSyntax(
base: buildableType.forceUnwrappedIfNeeded(expr: DeclReferenceExprSyntax(baseName: .identifier(varName))),
name: "text"
)
BinaryOperatorExprSyntax(text: "==")
StringLiteralExprSyntax(content: textChoice)
}
)
)
}
let disjunction = ExprListSyntax(
preconditionChoices.flatMap { [$0, ExprSyntax(BinaryOperatorExprSyntax(text: "||"))] }.dropLast()
)
return FunctionCallExprSyntax(callee: ExprSyntax("precondition")) {
LabeledExprSyntax(expression: SequenceExprSyntax(elements: disjunction))
}
}
}
|
