Swift NSScanner doesn't return start character

Question

I'm scanning an SVG path string, and using NSScanner to try and break it up into it's components. When it runs though I get the components, but I'm not getting back the "type"

For example: "m 186.14021,456.15955 3.19716,8.75681 c 1.78393"

Should return: "m 186.14021,456.15955 3.19716,8.75681"

Actual Result: "186.14021,456.15955 3.19716,8.75681"

Any ideas where my code is going awry?

import UIKit

let whitespaceAndPunctuationSet = NSMutableCharacterSet.whitespaceAndNewlineCharacterSet()
whitespaceAndPunctuationSet.formUnionWithCharacterSet(NSCharacterSet.punctuationCharacterSet())


var str = "m 186.14021,456.15955 3.19716,8.75681 c 1.78393,0.93528 30.33822,25.2032 27.48643,47.35972 -4.11654,31.98273 -39.24645,39.28157 -59.94003,28.99354 -20.69358,-10.28804 -17.12572,-56.58417 -14.98501,-58.45472 2.14072,-1.87055 24.97501,-80.4337 44.24145,-26.65535 z"
let characterSet = NSCharacterSet(charactersInString: "mlhvcsqtaz")
let aScanner = NSScanner(string: str)
aScanner.charactersToBeSkipped = whitespaceAndPunctuationSet

while aScanner.atEnd == false
{
    var testString:NSString?

    aScanner.scanUpToCharactersFromSet(characterSet, intoString: &testString)

    aScanner.scanCharactersFromSet(characterSet, intoString: nil)

    print(testString)
}

You've another problem haven't you? Can NSScanner turn 123-456 into 123 and -456? — Robert Longson, Sep 19 '15 at 09:31
Why don't you use an existing parser? Anyway, why aren't you using `scanCharactersFromSet` first to get the control char and then using `scanUpToCharactersFromSet` to get the points — Wain, Sep 19 '15 at 09:41

score 0 · Accepted Answer · answered Sep 19 '15 at 20:00

Ok, this seems to work:

import UIKit

let whitespaceAndPunctuationSet = NSMutableCharacterSet.whitespaceAndNewlineCharacterSet()
whitespaceAndPunctuationSet.formUnionWithCharacterSet(NSCharacterSet.punctuationCharacterSet())


var str = "m 186.14021,456.15955 3.19716,8.75681 c 1.78393,0.93528 30.33822,25.2032 27.48643,47.35972 -4.11654,31.98273 -39.24645,39.28157 -59.94003,28.99354 -20.69358,-10.28804 -17.12572,-56.58417 -14.98501,-58.45472 2.14072,-1.87055 24.97501,-80.4337 44.24145,-26.65535 z"
let characterSet = NSCharacterSet(charactersInString: "mlhvcsqtaz")
let aScanner = NSScanner(string: str)
aScanner.charactersToBeSkipped = whitespaceAndPunctuationSet

while aScanner.atEnd == false
{
    var testString:NSString?
    var controlChar:NSString?

    aScanner.scanCharactersFromSet(characterSet, intoString: &controlChar)

    aScanner.scanUpToCharactersFromSet(characterSet, intoString: &testString)

    print(controlChar)
    print(testString)
}

Swift NSScanner doesn't return start character

1 Answers1