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This checks: - The examples from the documentation of `reduce(_:_:)` and `reduce(into:_:)`. - Different levels of inference in the closure arguments being passed. - That the value passed as the `initialResult` remains unmodified.
91 lines
2.2 KiB
Swift
91 lines
2.2 KiB
Swift
//===--- Reduce.swift - tests for the two reduce variants -----------------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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// RUN: %target-run-simple-swift | %FileCheck %s
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// REQUIRES: executable_test
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// CHECK: testing...
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print("testing...")
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// Test the examples from the documentation of reduce(_:_:) and reduce(into:_:)
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let numbers = [1, 2, 3, 4]
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let numberSum = numbers.reduce(0, { x, y in
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x + y
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})
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// CHECK-NEXT: 10
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print(numberSum)
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let letters = "abracadabra"
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let letterCount = letters.reduce(into: [:]) { counts, letter in
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counts[letter, default: 0] += 1
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}
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// CHECK-NEXT: ["a", "b", "c", "d", "r"]
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print(letterCount.keys.sorted())
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print(letterCount["a"]!) // CHECK: 5
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print(letterCount["b"]!) // CHECK: 2
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print(letterCount["c"]!) // CHECK: 1
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print(letterCount["d"]!) // CHECK: 1
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print(letterCount["r"]!) // CHECK: 2
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// Test the two reduce methods with different levels of inference
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let numbers2 = Array(2..<7)
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// Test reduce(_:_:)
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// CHECK-NEXT: 20
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let sum1 = numbers2.reduce(0) { (x: Int, y: Int) -> Int in x + y }
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print(sum1)
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// CHECK-NEXT: 20
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let sum2 = numbers2.reduce(0) { (x, y) in x + y }
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print(sum2)
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// CHECK-NEXT: 20
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let sum3 = numbers2.reduce(0) { $0 + $1 }
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print(sum3)
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// CHECK-NEXT: 20
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let sum4 = numbers2.reduce(0, +)
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print(sum4)
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// Test reduce(into:_:)
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// CHECK-NEXT: 20
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let sum5 = numbers2.reduce(into: 0) { (x: inout Int, y: Int) in x += y }
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print(sum5)
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// CHECK-NEXT: 20
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let sum6 = numbers2.reduce(into: 0) { x, y in x += y }
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print(sum6)
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// CHECK-NEXT: 20
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let sum7 = numbers2.reduce(into: 0) { $0 += $1 }
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print(sum7)
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// CHECK-NEXT: 20
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let sum8 = numbers2.reduce(into: 0, +=)
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print(sum8)
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// Test that the initial value remains unmodified
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var original = [0, 1]
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let result = numbers2.reduce(into: original) { acc, x in
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acc.append(x)
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}
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// CHECK-NEXT: [0, 1]
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print(original)
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// CHECK-NEXT: [0, 1, 2, 3, 4, 5, 6]
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print(result)
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// CHECK: all done.
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print("all done.")
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