A command line tool to output words from input text, reading from stdin or from a passed file.

words.swift

// Usage: echo "these are some words" | words

// Output:
// these
// are
// some
// words

import Foundation
import Swift

public struct StderrOutputStream: OutputStreamType {
    public static let stream = StderrOutputStream()
    public func write(string: String) {fputs(string, stderr)}
}
public var errStream = StderrOutputStream.stream

let tagger = NSLinguisticTagger(tagSchemes: [NSLinguisticTagSchemeTokenType], options: Int(NSLinguisticTaggerOptions.JoinNames.rawValue))

let args = Process.arguments
let input: NSString

var fileHandle = NSFileHandle.fileHandleWithStandardInput()

if args.count > 1 {
    guard let handle = NSFileHandle(forReadingAtPath: args[1]) else {
        print("Invalid input file", toStream: &errStream)
        exit(1)
    }
    fileHandle = handle
}

let inputData = fileHandle.readDataToEndOfFile()
guard let handleInput = NSString(data:inputData, encoding: NSUTF8StringEncoding) else {
    print("Unable to read input as text", toStream: &errStream)
    exit(1)
}
input = handleInput

tagger.string = input as String
let range = NSMakeRange(0, input.length)
tagger.enumerateTagsInRange(range, scheme: NSLinguisticTagSchemeTokenType,
                            options: [NSLinguisticTaggerOptions.OmitOther,
                                NSLinguisticTaggerOptions.OmitPunctuation,
                                NSLinguisticTaggerOptions.OmitWhitespace]
) { (tag, tokenRange, sentenceRange, stopPtr) in
    let word = input.substringWithRange(tokenRange)
    print(word.lowercaseString)
}