NSRegularExpression (.*) any single character zero or more times doesn't work-CodePudding

My regex which will be used for code liniting purpose should find a function definitions which have first line empty.

Here is my string:

let text = """
    override func withFirstLineEmpty(_ animated: Bool) {

        print()
    }
    
    override func withNoFirstLineEmpty(_ animated: Bool) {
        print()
    }
"""

This is my regex which was tested with regex101 website: func.*{\n\n

This is my code:

let regexString = "func.*{\n\n"
let regexEscaped = NSRegularExpression.escapedPattern(for: regexString)
let regex = try! NSRegularExpression(pattern: regexEscaped, options: [.useUnixLineSeparators, .dotMatchesLineSeparators])
let matches = regex.matches(in: text, options: [], range: NSRange(text)!)

matches array of results is empty.

Is this a problem of my regex or NSRegularExpression configuration?

CodePudding user response：

It's highly recommended to search for \s which includes both \n and \r

And basically the NSRange is wrong. You have to use the dedicated initializer NSRange(_:in:). And the escapedPattern line is actually not needed. There is a native Swift syntax. On the other hand the { must be escaped.

let text = """
    override func withFirstLineEmpty(_ animated: Bool) {

        print()
    }
    
    override func withFirstLineEmpty(_ animated: Bool) {
        print()
    }
"""

let regexString = #"func.*\{\s{2}"#
let regex = try! NSRegularExpression(pattern: regexString)
let matches = regex.matches(in: text, range: NSRange(text.startIndex..., in: text))