dduan

Remove type inference for stored properties

• Proposal: SE-NNNN
• Authors: Daniel Duan
• Review Manager: TBD
• Status: Awaiting review

Introduction

When a type's stored property is declared with a default value, user may choose to let Swift's compiler to automatically deduct type for this property instead of writing it explicitly. We propose this feature be removed from Swift.

dduan

#!/usr/bin/env python
# -*- coding: utf-8 -*-
'''Print cached git diff stats in less than 50 characters.

This script takes output from `git diff --cached --stat` and generates a single
line summary with less than 50 characters. This output may be used as a
(hopefully) temporary commit message like so

git commit -m "`blah.py`"

dduan

import UIKit

class TestView: UIView {
    @IBInspectable private var string: String = ""
    @IBInspectable private var stringiuo: String!
    @IBInspectable private var stringoptional: String?
    @IBInspectable private var iuostring: ImplicitlyUnwrappedOptional<String>
    @IBInspectable private var optionalstring: Optional<String>
    @IBInspectable private var nsstring: NSString = ""
    @IBInspectable private var nsstringiuo: NSString!

dduan

# usage:
#    IFS=$'\n' find ROOT_SOURCE_FOLDER -name "*.swift" -exec python PATH/TO/migrate.py {} \;
import sys
import re

func = re.compile('func\s+\w+\(')
param = re.compile('(?P<indent>\s*)/// -[ ]*[pP]arameter[ ]+(?P<name>\w+)[ ]*:(?P<description>[^\n]+)\n')
ret = re.compile('(?P<indent>\s*)/// -[ ]*[rR]eturns[ ]*:(?P<description>[^\n]+)\n')
continuation = re.compile('\s*///(?P<description>[^\n]+)')

dduan

enum OneArray<T> {
  case one(T)
  case many([T])

  // Want empty value? Fuck you.
  init?<S: Sequence where S.Iterator.Element == T>(_ s: S) {
    switch s.underestimatedCount {
    case 0:
      return nil
    case 1:

dduan

protocol X {
    var value: Int { get }
    init(value: Int)
}

func foo<T, U: X>(a: T) -> U {
    return U(value: a.value)
}

dduan

public struct DefaultDictionary<Key : Hashable, Value>: CollectionType {

    private var _storage: [Key: Value]
    private var _defaultValue: () -> Value

    public typealias Element = (Key, Value)
    public typealias Index = DictionaryIndex<Key, Value>

    public var startIndex: Index {
        return _storage.startIndex

dduan

func f<T, U>(x: T.Type, _ y: U) -> Bool {
    return y is T
}

func g<T, U>(x: T, _ y: U) -> Bool {
    return y is T
}

protocol P {}
class B: P {}

dduan

# run this in the swift source code folder to get a list of radars
for i in $(grep -hor -E 'rdar://problem/[0-9]+' stdlib lib | sed 's/rdar:\/\/problem\///'); do if [[ ! -z $(curl -s "http://www.openradar.me/$i" | grep 'Tell us more!') ]]; then echo rdar://problem/$i; fi; done

dduan

// this is almost good, if only Swift allows specifying precedence for pre/postfix operators.
struct Dollar {}
let $ = Dollar()

struct BInt: IntegerLiteralConvertible {
    let bool: Bool
    let int: UInt
    func relativeTo(total: Int) -> Int {
        return bool ? total - Int(int) : Int(int)
    }