Swift - 小さなツールの作成: 1つのことだけをうまくやる(入力と出力をパイプでつなぐ(CSV形式をJSON形式に変換))

The Swift Programming Language
Apple Inc.

開発環境

• OS X Mavericks - Apple(OS)
• Xcode 6.0 Beta
• Swift (プログラミング言語)

Head First C ―頭とからだで覚えるCの基本(David Griffiths (著)、Dawn Griffiths (著) 中田 秀基(監訳)(翻訳)、木下 哲也 (翻訳)、オライリージャパン)の3章(小さなツールの作成: 1つのことだけどうまくやる)、プールパズル(p.133)をSwiftで考えてみる。

プールパズル(p.133)

コード(Xcode)

stdin.swift

//
//  stdin.swift
//  stdin
//
//  Created by kamimura on 8/19/14.
//  Copyright (c) 2014 kamimura. All rights reserved.
//

import Foundation

// 標準入力(STDIN)から読み込む
func input(msg:String = "") -> String {
    print(msg)
    var in_fh = NSFileHandle.fileHandleWithStandardInput()
    var data = in_fh.availableData
    var s = NSString(data: data, encoding: NSUTF8StringEncoding)
    s = s.substringToIndex(s.length - 1)
    return s
}

string.swift

//
//  string.swift
//  string
//
//  Created by kamimura on 8/10/14.
//  Copyright (c) 2014 kamimura. All rights reserved.
//

import Foundation

extension String {
    var swapcaseString:String {
    var result: String = ""
        for ch in self {
            let s = String(ch)
            result += s.uppercaseString == s ? s.lowercaseString : s.uppercaseString
        }
        return result
    }
    var isUpper:Bool { return self.uppercaseString == self }
    var isLower:Bool { return self.lowercaseString == self }
    var length:Int { return (self as NSString).length }
    var strip:String { return self.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())}
    var floatValue:Float { return (self as NSString).floatValue }
    var doubleValue:Double { return (self as NSString).doubleValue }
    func count(sub:String) -> Int {
        var result:Int = 0
        var s = self
        let index:String.Index = "a".endIndex
        while s != "" {
            if s.hasPrefix(sub) {
                result += 1
                s = s.substringFromIndex(sub.endIndex)
            } else {
                s = s.substringFromIndex(index)
            }
            
        }
        return result
    }
    func find(sub:String, start:Int = 0, end:Int? = nil) -> Int {
        var s = self as NSString
        var s_temp = s.substringFromIndex(start)
        let end_temp:Int = end ? end! : s.length
        for i in start..<end_temp {
            if (s_temp.hasPrefix(sub)) {
                return i
            }
            s_temp = s.substringFromIndex(i + 1) as NSString
        }
        return -1
    }
    func replace(old_str:String, new_str:String) -> String {
        return self.stringByReplacingOccurrencesOfString(old_str, withString: new_str)
    }
    func slice(start:Int=0, end:Int?=nil) -> String {
        let s = self as NSString
        var new_end:Int
        if (end) {
            new_end = end!
        } else {
            new_end = s.length
        }
        return  s.substringWithRange(NSRange(location: start, length:new_end - start))
    }
    func split(sep:String = "") -> [String] {
        var result:[String] = []
        if (sep == "") {
            for ch in self {
                result.append(String(ch))
            }
            return result
        }
        var s:String = self
        var len = sep.length
        var temp:String = ""
        while s != "" {
            if s.hasPrefix(sep) {
                if temp != "" {
                    result.append(temp)
                    temp = ""
                }
                s = s.slice(start: len)
            } else {
                temp += s.slice(start: 0, end: 1)
                s = s.slice(start: 1)
            }
        }
        if temp != "" {
            result.append(temp)
        }
        return result
    }
    var reversed:String { return "".join(self.split().reverse()) }
}

bermuda(main.swift, string.swift, stdin.swift)

main.swift

//
//  main.swift
//  bermuda
//
//  Created by kamimura on 8/19/14.
//  Copyright (c) 2014 kamimura. All rights reserved.
//

import Foundation

let s:String = input()

for line:String in s.split(sep: "\n") {
    let a:[String] = line.split(sep: ",")
    let latitude:Float = a[0].floatValue
    let longitude:Float = a[1].floatValue
    let info:String = a[2]
    if latitude > 26 && latitude < 34 && longitude > -76 && longitude < -64 {
        print("\(latitude),\(longitude),\(info)")
    }
}

geo2json(main.swift, string.Swift, stdin.swift)

main.swift

//
//  main.swift
//  geo2json
//
//  Created by kamimura on 8/19/14.
//  Copyright (c) 2014 kamimura. All rights reserved.
//

import Foundation

let csv:String = input()

var started:Bool = false

println("data=[")

for line:String in csv.split(sep: "\n") {
    let values = line.split(sep: ",")
    let latitude:Float = values[0].floatValue
    let longitude:Float = values[1].floatValue
    let info:String = values[2]
    if started {
        println(",")
    } else {
        started = true
    }
    if latitude < -90 || latitude > 90 {
        println("緯度に問題があります。\(latitude)")
        break
    }
    if longitude < -180 || longitude > 180 {
        println("経度に問題があります。\(longitude)")
        break
    }
    print("{latitude: \(values[0]), longitude: \(values[1]), info: '\(values[2])'}")
}

println("\n]")

入出力結果(Console Output, Terminal)

$ ( ./bermuda | ./geo2json ) < gpsdata.csv > output.json
$ cat output.json 
data=[
{latitude: 30.0, longitude: -70.0, info: 'Speed = 20'}
]
$ cat gpsdata.csv 
42.363400,-710.098465,Speed = 21
42.363327,-71.097588,Speed = 23
30.0,-70.0,Speed = 20
42.363255,-71.096710,Speed = 17
$