63 lines
2.6 KiB
Swift
63 lines
2.6 KiB
Swift
import SourceKittenFramework
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public struct LastWhereRule: CallPairRule, OptInRule, ConfigurationProviderRule, AutomaticTestableRule {
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public var configuration = SeverityConfiguration(.warning)
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public init() {}
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public static let description = RuleDescription(
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identifier: "last_where",
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name: "Last Where",
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description: "Prefer using `.last(where:)` over `.filter { }.last` in collections.",
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kind: .performance,
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minSwiftVersion: .fourDotTwo,
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nonTriggeringExamples: [
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Example("kinds.filter(excludingKinds.contains).isEmpty && kinds.last == .identifier\n"),
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Example("myList.last(where: { $0 % 2 == 0 })\n"),
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Example("match(pattern: pattern).filter { $0.last == .identifier }\n"),
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Example("(myList.filter { $0 == 1 }.suffix(2)).last\n"),
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Example("collection.filter(\"stringCol = '3'\").last")
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],
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triggeringExamples: [
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Example("↓myList.filter { $0 % 2 == 0 }.last\n"),
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Example("↓myList.filter({ $0 % 2 == 0 }).last\n"),
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Example("↓myList.map { $0 + 1 }.filter({ $0 % 2 == 0 }).last\n"),
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Example("↓myList.map { $0 + 1 }.filter({ $0 % 2 == 0 }).last?.something()\n"),
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Example("↓myList.filter(someFunction).last\n"),
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Example("↓myList.filter({ $0 % 2 == 0 })\n.last\n"),
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Example("(↓myList.filter { $0 == 1 }).last\n")
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]
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)
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public func validate(file: SwiftLintFile) -> [StyleViolation] {
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return validate(file: file,
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pattern: "[\\}\\)]\\s*\\.last",
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patternSyntaxKinds: [.identifier],
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callNameSuffix: ".filter",
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severity: configuration.severity) { dictionary in
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let substructure: [SourceKittenDictionary] = {
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if SwiftVersion.current >= .fiveDotSix {
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return dictionary.substructure.flatMap { dict -> [SourceKittenDictionary] in
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if dict.expressionKind == .argument {
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return dict.substructure
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}
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return [dict]
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}
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}
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return dictionary.substructure
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}()
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if substructure.isNotEmpty {
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return true // has a substructure, like a closure
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}
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guard let bodyRange = dictionary.bodyByteRange else {
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return true
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}
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let syntaxKinds = file.syntaxMap.kinds(inByteRange: bodyRange)
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return !syntaxKinds.contains(.string)
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}
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}
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}
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