qrcli.swift

// % swift qrcli.swift TEST > qrcode.png
// or, % swift build -Xswiftc -framework -Xswiftc CoreImage

import CoreImage
import class AppKit.NSBitmapImageRep

func qrcode(_ text: String) -> CIImage {
    let filter = CIFilter(name: "CIQRCodeGenerator")!
    filter.setValue(text.data(using: .shiftJIS), forKey: "inputMessage")
    filter.setValue("M", forKey: "inputCorrectionLevel")
    return filter.outputImage!
}

extension CIImage {
    var png: Data {
        return NSBitmapImageRep(ciImage: self).representation(using: .png, properties: [:])!
    }
}

let text = CommandLine.arguments[1]
let png = qrcode(text).png
FileHandle.standardOutput.write(png)