macOS String Processing Swift Samples

// macOS Swift String Split/Join Examples
// Using Swift standard library

import Foundation

// 1. Basic String Splitting
class StringSplitting {

    static func demonstrateBasicSplit() {
        print("\n--- Basic String Splitting ---")

        let sentence = "Hello world from Swift"
        let words = sentence.split(separator: " ")
        print("Original: \(sentence)")
        print("Split by space: \(words)")

        // Split by character
        let text = "apple,banana,cherry,date"
        let fruits = text.split(separator: ",")
        print("\nSplit by comma: \(fruits)")

        // Split into lines
        let multiline = """
        Line 1
        Line 2
        Line 3
        """
        let lines = multiline.split(separator: "\n")
        print("\nSplit into lines: \(lines)")

        // Using components
        let components = sentence.components(separatedBy: " ")
        print("\nComponents separated by space: \(components)")
    }
}

// 2. Advanced Splitting
class AdvancedSplitting {

    static func demonstrateAdvancedSplit() {
        print("\n--- Advanced Splitting ---")

        // Split by multiple separators
        let text = "apple, banana; cherry| date"
        let separators = CharacterSet(charactersIn: ",;|")
        let parts = text.components(separatedBy: separators)
        print("Split by multiple separators: \(parts)")

        // Split with max splits
        let data = "key1=value1,key2=value2,key3=value3"
        let limited = data.components(separatedBy: ",")
        print("\nSplit limited: \(limited)")

        // Split by whitespace
        let whitespace = "  Hello   world  \tfrom  \nSwift  "
        let trimmedWords = whitespace.split(separator: " ").filter { !$0.isEmpty }
        print("\nSplit by whitespace: \(Array(trimmedWords))")

        // Split by character set
        let messyText = "Hello123World456Swift789"
        let numbers = CharacterSet.decimalDigits
        let nonNumbers = messyText.components(separatedBy: numbers).filter { !$0.isEmpty }
        print("\nSplit removing numbers: \(nonNumbers)")

        // Split keeping delimiters
        func splitKeepingDelimiters(_ text: String, delimiter: String) -> [String] {
            var result: [String] = []
            var remaining = text

            while let range = remaining.range(of: delimiter) {
                let before = String(remaining[..<range.lowerBound])
                result.append(before)
                result.append(delimiter)
                remaining = String(remaining[range.upperBound...])
            }
            result.append(remaining)

            return result.filter { !$0.isEmpty }
        }

        let withDelimiters = splitKeepingDelimiters("a,b,c", delimiter: ",")
        print("\nSplit keeping delimiters: \(withDelimiters)")
    }
}

// 3. String Joining
class StringJoining {

    static func demonstrateJoining() {
        print("\n--- String Joining ---")

        // Join array with separator
        let words = ["Hello", "world", "from", "Swift"]
        let joined = words.joined(separator: " ")
        print("Words: \(words)")
        print("Joined with space: \(joined)")

        // Join with different separators
        let fruits = ["Apple", "Banana", "Cherry"]
        print("Comma-separated: \(fruits.joined(separator: ", "))")
        print("Pipe-separated: \(fruits.joined(separator: " | "))")
        print("Newline-separated:\n\(fruits.joined(separator: "\n"))")

        // Join without separator
        let letters = ["S", "w", "i", "f", "t"]
        print("\nJoined without separator: \(letters.joined())")

        // Join numbers
        let numbers = [1, 2, 3, 4, 5]
        let numberString = numbers.map { String($0) }.joined(separator: "-")
        print("\nNumbers joined: \(numberString)")

        // Join with prefix/suffix
        let lines = ["Line 1", "Line 2", "Line 3"]
        let quoted = lines.map { "\"\($0)\"" }.joined(separator: ", ")
        print("\nQuoted lines: \(quoted)")
    }
}

// 4. Split and Join Combinations
class SplitJoinCombinations {

    static func demonstrateCombinations() {
        print("\n--- Split and Join Combinations ---")

        // Replace separator
        let text = "apple,banana,cherry,date"
        let pipeSeparated = text.split(separator: ",").joined(separator: " | ")
        print("Original: \(text)")
        print("With pipes: \(pipeSeparated)")

        // Remove duplicates and join
        let duplicates = "apple,banana,apple,cherry,banana,date"
        let unique = Array(Set(duplicates.components(separatedBy: ","))).sorted().joined(separator: ",")
        print("\nRemove duplicates: \(unique)")

        // Filter and join
        let numbers = "1,2,3,4,5,6,7,8,9,10"
        let evens = numbers.split(separator: ",")
            .compactMap { Int($0) }
            .filter { $0 % 2 == 0 }
            .map { String($0) }
            .joined(separator: ",")
        print("\nEven numbers: \(evens)")

        // Transform and join
        let names = "alice,bob,charlie"
        let capitalized = names.split(separator: ",")
            .map { $0.capitalized }
            .joined(separator: ", ")
        print("\nCapitalized: \(capitalized)")

        // Word count
        let paragraph = "This is a sample paragraph with several words"
        let wordCount = paragraph.split(separator: " ").count
        print("\nWord count: \(wordCount)")

        // Parse CSV-like data
        let csv = "name,age,city\nJohn,30,NYC\nJane,25,LA"
        let rows = csv.split(separator: "\n")
        print("\nCSV rows:")
        for row in rows {
            let columns = row.split(separator: ",")
            print("  \(columns)")
        }
    }
}

// 5. String Trimming and Padding
class StringTrimmingPadding {

    static func demonstrateTrimmingPadding() {
        print("\n--- String Trimming and Padding ---")

        // Trim whitespace
        let messy = "  Hello World  "
        print("Original: '\(messy)'")
        print("Trimmed: '\(messy.trimmingCharacters(in: .whitespaces))'")

        // Trim specific characters
        let stars = "***Hello***"
        print("\nOriginal: '\(stars)'")
        print("Trimmed stars: '\(stars.trimmingCharacters(in: CharacterSet(charactersIn: "*")))'")

        // Trim newlines
        let withNewlines = "\nHello\n\n"
        print("\nWith newlines: '\(withNewlines)'")
        print("Trimmed: '\(withNewlines.trimmingCharacters(in: .newlines))'")

        // Left pad
        func leftPad(_ string: String, toLength length: Int, with pad: String = " ") -> String {
            let padding = String(repeating: pad, count: max(0, length - string.count))
            return padding + string
        }

        print("\nLeft pad:")
        print("  '5' -> '\(leftPad("5", toLength: 3, with: "0"))'")
        print("  '123' -> '\(leftPad("123", toLength: 5, with: "0"))'")

        // Right pad
        func rightPad(_ string: String, toLength length: Int, with pad: String = " ") -> String {
            let padding = String(repeating: pad, count: max(0, length - string.count))
            return string + padding
        }

        print("\nRight pad:")
        print("  'hi' -> '\(rightPad("hi", toLength: 5, with: "*"))'")
        print("  'hello' -> '\(rightPad("hello", toLength: 10, with: "-"))'")

        // Center pad
        func centerPad(_ string: String, toLength length: Int, with pad: String = " ") -> String {
            let totalPad = max(0, length - string.count)
            let leftPad = totalPad / 2
            let rightPad = totalPad - leftPad
            return String(repeating: pad, count: leftPad) + string + String(repeating: pad, count: rightPad)
        }

        print("\nCenter pad:")
        print("  'test' -> '\(centerPad("test", toLength: 10, with: "-"))'")
        print("  'abc' -> '\(centerPad("abc", toLength: 9, with: "*"))'")
    }
}

// 6. String Parsing
class StringParsing {

    static func demonstrateParsing() {
        print("\n--- String Parsing ---")

        // Parse key-value pairs
        let query = "name=John&age=30&city=NYC"
        var params: [String: String] = [:]

        for pair in query.split(separator: "&") {
            let keyValue = pair.split(separator: "=")
            if keyValue.count == 2 {
                params[String(keyValue[0])] = String(keyValue[1])
            }
        }

        print("Query parameters: \(params)")

        // Parse CSV
        let csv = "John,30,New York\nJane,25,Los Angeles\nBob,35,Chicago"
        print("\nCSV Parsing:")
        for line in csv.split(separator: "\n") {
            let fields = line.split(separator: ",")
            print("  Name: \(fields[0]), Age: \(fields[1]), City: \(fields[2])")
        }

        // Parse file path
        let path = "/Users/john/Documents/file.txt"
        let components = path.split(separator: "/")
        print("\nPath components: \(Array(components))")
        print("Filename: \(components.last ?? "")")
        print("Directory: \(components.dropLast().joined(separator: "/"))")

        // Parse URL
        let url = "https://example.com/path/to/page?param=value"
        if let urlComponents = URLComponents(string: url) {
            print("\nURL Parsing:")
            print("  Scheme: \(urlComponents.scheme ?? "")")
            print("  Host: \(urlComponents.host ?? "")")
            print("  Path: \(urlComponents.path)")
        }

        // Parse words by sentence
        let text = "Hello world. How are you? I'm fine!"
        let sentences = text.split(separator: ".").map { $0.trimmingCharacters(in: .whitespaces) }
        print("\nSentences: \(sentences)")
    }
}

// 7. String Building
class StringBuilder {

    static func demonstrateBuilding() {
        print("\n--- String Building ---")

        // Using += operator
        var result1 = ""
        for i in 1...5 {
            result1 += "\(i) "
        }
        print("Using +=: '\(result1)'")

        // Using append
        var result2 = ""
        result2.append("Hello")
        result2.append(" ")
        result2.append("World")
        print("Using append: '\(result2)'")

        // Using join
        let parts = ["Hello", " ", "World", "!", " ", "From", " ", "Swift"]
        let result3 = parts.joined()
        print("Using join: '\(result3)'")

        // Using StringInterpolation
        let name = "John"
        let age = 30
        let result4 = "Name: \(name), Age: \(age)"
        print("\nUsing interpolation: '\(result4)'")

        // Large string building efficient
        let largeParts = (1...1000).map { "Item\($0)" }
        let startTime = Date()
        let largeString = largeParts.joined(separator: ", ")
        let elapsed = Date().timeIntervalSince(startTime)
        print("\nBuilt string of \(largeString.count) chars in \(elapsed * 1000)ms")
    }
}

// 8. String Statistics
class StringStatistics {

    static func demonstrateStatistics() {
        print("\n--- String Statistics ---")

        let text = "Hello World from Swift"

        // Character count
        print("Character count: \(text.count)")

        // Word count
        let wordCount = text.split(separator: " ").count
        print("Word count: \(wordCount)")

        // Line count
        let multiline = "Line 1\nLine 2\nLine 3\nLine 4"
        let lineCount = multiline.split(separator: "\n").count
        print("Line count: \(lineCount)")

        // Unique characters
        let uniqueChars = Set(text)
        print("Unique characters: \(uniqueChars.count)")

        // Character frequency
        let chars = Array(text.lowercased().filter { !$0.isWhitespace })
        var frequency: [Character: Int] = [:]

        for char in chars {
            frequency[char, default: 0] += 1
        }

        print("\nCharacter frequency:")
        for (char, count) in frequency.sorted(by: { $0.value > $1.value }) {
            print("  '\(char)': \(count)")
        }

        // Average word length
        let words = text.split(separator: " ")
        let avgLength = words.reduce(0) { $0 + $1.count } / words.count
        print("\nAverage word length: \(avgLength)")

        // Longest word
        if let longest = words.max(by: { $0.count < $1.count }) {
            print("Longest word: '\(longest)' (\(longest.count) chars)")
        }
    }
}

// 9. Path Operations
class PathOperations {

    static func demonstratePaths() {
        print("\n--- Path Operations ---")

        let path = "/Users/john/Documents/file.txt"

        // Get components
        let components = path.split(separator: "/").map { String($0) }
        print("Path components: \(components)")

        // Get filename
        let filename = (path as NSString).lastPathComponent
        print("Filename: \(filename)")

        // Get extension
        let fileExtension = (path as NSString).pathExtension
        print("Extension: \(fileExtension)")

        // Get directory
        let directory = (path as NSString).deletingLastPathComponent
        print("Directory: \(directory)")

        // Join paths
        let newFilename = "data.json"
        let newPath = (directory as NSString).appendingPathComponent(newFilename)
        print("New path: \(newPath)")

        // Normalize path
        let messyPath = "/Users//john/./Documents/../john/file.txt"
        let normalized = (messyPath as NSString).standardizingPath
        print("\nNormalized path: \(normalized)")
    }
}

// 10. Advanced String Manipulation
class AdvancedManipulation {

    static func demonstrateAdvanced() {
        print("\n--- Advanced String Manipulation ---")

        // Reverse string
        let original = "Hello Swift"
        let reversed = String(original.reversed())
        print("Original: \(original)")
        print("Reversed: \(reversed)")

        // Shuffle string
        let toShuffle = "abcdef"
        let shuffled = toShuffle.shuffled()
        print("\nOriginal: \(toShuffle)")
        print("Shuffled: \(String(shuffled))")

        // Remove characters at positions
        let text = "Hello World"
        let indicesToRemove = [1, 5, 8]
        let filtered = text.enumerated()
            .filter { !indicesToRemove.contains($0.offset) }
            .map { String($0.element) }
            .joined()
        print("\nOriginal: \(text)")
        print("Removed at [1,5,8]: \(filtered)")

        // Insert at position
        func insert(_ string: String, at position: Int, _ toInsert: String) -> String {
            let index = string.index(string.startIndex, offsetBy: position)
            return string.prefix(position) + toInsert + string.suffix(from: index)
        }

        let base = "Hello World"
        let inserted = insert(base, at: 5, " Beautiful")
        print("\nOriginal: \(base)")
        print("Inserted at 5: \(inserted)")

        // Extract substrings
        let longText = "The quick brown fox jumps over the lazy dog"
        let startIndex = longText.index(longText.startIndex, offsetBy: 4)
        let endIndex = longText.index(longText.startIndex, offsetBy: 9)
        let substring = String(longText[startIndex..<endIndex])
        print("\nSubstring [4:9]: '\(substring)'")

        // First n characters
        let first5 = String(longText.prefix(5))
        print("First 5: '\(first5)'")

        // Last n characters
        let last3 = String(longText.suffix(3))
        print("Last 3: '\(last3)'")
    }
}

// Main demonstration
func demonstrateStringSplitJoin() {
    print("=== macOS Swift String Split/Join Examples ===")

    StringSplitting.demonstrateBasicSplit()
    AdvancedSplitting.demonstrateAdvancedSplit()
    StringJoining.demonstrateJoining()
    SplitJoinCombinations.demonstrateCombinations()
    StringTrimmingPadding.demonstrateTrimmingPadding()
    StringParsing.demonstrateParsing()
    StringBuilder.demonstrateBuilding()
    StringStatistics.demonstrateStatistics()
    PathOperations.demonstratePaths()
    AdvancedManipulation.demonstrateAdvanced()

    print("\n=== All String Split/Join Examples Completed ===")
}

// Run demonstration
demonstrateStringSplitJoin()

// macOS Swift Regular Expression Examples
// Using NSRegularExpression and Swift Regex

import Foundation

// 1. Basic Pattern Matching
class BasicRegex {

    static func demonstrateBasicMatching() {
        print("\n--- Basic Pattern Matching ---")

        let text = "Hello World! Swift is awesome. Welcome to Swift programming."

        // Simple match
        if let range = text.range(of: "Swift", options: .regularExpression) {
            print("Found 'Swift' at: \(range)")
        }

        // Match digits
        let numberPattern = "\d+"
        if let _ = text.range(of: numberPattern, options: .regularExpression) {
            print("Found numbers in text")
        }

        // Match word
        let wordPattern = "\b\w{5}\b" // 5-letter words
        if let range = text.range(of: wordPattern, options: .regularExpression) {
            let word = String(text[range])
            print("Found 5-letter word: \(word)")
        }
    }
}

// 2. NSRegularExpression Usage
class NSRegularExpressionExamples {

    static func demonstrateNSRegularExpression() {
        print("\n--- NSRegularExpression ---")

        let text = "Emails: [email protected], [email protected], [email protected]"

        do {
            // Email pattern
            let emailPattern = "[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}"
            let regex = try NSRegularExpression(pattern: emailPattern)

            let range = NSRange(text.startIndex..., in: text)
            let matches = regex.matches(in: text, range: range)

            print("Found \(matches.count) emails:")
            for match in matches {
                if let range = Range(match.range, in: text) {
                    print("  \(String(text[range]))")
                }
            }

        } catch {
            print("Regex error: \(error)")
        }
    }
}

// 3. Text Validation
class RegexValidation {

    static func demonstrateValidation() {
        print("\n--- Regex Validation ---")

        // Email validation
        func isValidEmail(_ email: String) -> Bool {
            let pattern = "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,}"
            let predicate = NSPredicate(format: "SELF MATCHES %@", pattern)
            return predicate.evaluate(with: email)
        }

        print("Email validation:")
        print("  [email protected]: \(isValidEmail("john@example.com"))")
        print("  invalid.email: \(isValidEmail("invalid.email"))")

        // Phone number validation
        func isValidPhone(_ phone: String) -> Bool {
            let pattern = "^\\d{3}-\\d{3}-\\d{4}$"
            let predicate = NSPredicate(format: "SELF MATCHES %@", pattern)
            return predicate.evaluate(with: phone)
        }

        print("\nPhone validation (XXX-XXX-XXXX):")
        print("  123-456-7890: \(isValidPhone("123-456-7890"))")
        print("  12-345-67890: \(isValidPhone("12-345-67890"))")

        // URL validation
        func isValidURL(_ url: String) -> Bool {
            let pattern = "^(https?:\\/\\/)?([\\da-z\\.-]+)\\.([a-z\\.]{2,6})([\/\\w \\.-]*)*\\/?$"
            let predicate = NSPredicate(format: "SELF MATCHES %@", pattern)
            return predicate.evaluate(with: url)
        }

        print("\nURL validation:")
        print("  https://example.com: \(isValidURL("https://example.com"))")
        print("  not-a-url: \(isValidURL("not-a-url"))")

        // Password strength
        func isStrongPassword(_ password: String) -> Bool {
            // At least 8 chars, 1 uppercase, 1 lowercase, 1 number
            let pattern = "^(?=.*[a-z])(?=.*[A-Z])(?=.*\\d).{8,}$"
            let predicate = NSPredicate(format: "SELF MATCHES %@", pattern)
            return predicate.evaluate(with: password)
        }

        print("\nPassword validation:")
        print("  Pass123: \(isStrongPassword("Pass123"))")
        print("  weak: \(isStrongPassword("weak"))")
        print("  StrongPass123: \(isStrongPassword("StrongPass123"))")
    }
}

// 4. Text Extraction
class RegexExtraction {

    static func demonstrateExtraction() {
        print("\n--- Text Extraction ---")

        let text = """
        The prices are: $19.99, $29.99, and $5.50.
        Contact us at [email protected] or [email protected].
        Phone numbers: 123-456-7890, 987-654-3210
        """

        // Extract prices
        extractAndPrint(text, pattern: "\\$\\d+\\.\\d{2}", label: "Prices")

        // Extract emails
        extractAndPrint(text, pattern: "[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\\.[a-zA-Z]{2,}", label: "Emails")

        // Extract phone numbers
        extractAndPrint(text, pattern: "\\d{3}-\\d{3}-\\d{4}", label: "Phone numbers")

        // Extract URLs
        let html = "Visit https://example.com and http://test.org for info"
        extractAndPrint(html, pattern: "https?:\\/\\/[^\\s]+", label: "URLs")

        // Extract dates
        let dates = "Events: 2024-01-15, 2024-02-20, 2024-03-25"
        extractAndPrint(dates, pattern: "\\d{4}-\\d{2}-\\d{2}", label: "Dates")

        // Extract hashtags
        let social = "Check out #Swift and #Programming and #iOSDev"
        extractAndPrint(social, pattern: "#\\w+", label: "Hashtags")

        // Extract mentions
        let mentions = "Hello @john and @jane, welcome @all"
        extractAndPrint(mentions, pattern: "@\\w+", label: "Mentions")
    }

    private static func extractAndPrint(_ text: String, pattern: String, label: String) {
        do {
            let regex = try NSRegularExpression(pattern: pattern)
            let range = NSRange(text.startIndex..., in: text)
            let matches = regex.matches(in: text, range: range)

            print("\n\(label):")
            for match in matches {
                if let range = Range(match.range, in: text) {
                    print("  \(String(text[range]))")
                }
            }
        } catch {
            print("Error extracting \(label): \(error)")
        }
    }
}

// 5. Text Replacement
class RegexReplacement {

    static func demonstrateReplacement() {
        print("\n--- Regex Replacement ---")

        // Mask phone numbers
        func maskPhoneNumbers(_ text: String) -> String {
            let pattern = "(\\d{3})-(\\d{3})-(\\d{4})"
            return text.replacingOccurrences(
                of: pattern,
                with: "$1-XXX-$3",
                options: .regularExpression
            )
        }

        let phones = "Call 123-456-7890 or 987-654-3210"
        print("Original: \(phones)")
        print("Masked: \(maskPhoneNumbers(phones))")

        // Remove special characters
        func removeSpecialChars(_ text: String) -> String {
            let pattern = "[^a-zA-Z0-9\\s]"
            return text.replacingOccurrences(
                of: pattern,
                with: "",
                options: .regularExpression
            )
        }

        let messy = "Hello! @World #123 $Test"
        print("\nOriginal: \(messy)")
        print("Cleaned: \(removeSpecialChars(messy))")

        // Normalize whitespace
        func normalizeWhitespace(_ text: String) -> String {
            let pattern = "\\s+"
            return text.replacingOccurrences(
                of: pattern,
                with: " ",
                options: .regularExpression
            ).trimmingCharacters(in: .whitespaces)
        }

        let messyText = "  Hello    world   from   Swift  "
        print("\nOriginal: '\(messyText)'")
        print("Normalized: '\(normalizeWhitespace(messyText))'")

        // Format phone numbers
        func formatPhone(_ text: String) -> String {
            let pattern = "(\\d{3})(\\d{3})(\\d{4})"
            return text.replacingOccurrences(
                of: pattern,
                with: "($1) $2-$3",
                options: .regularExpression
            )
        }

        let plainPhone = "1234567890"
        print("\nPlain: \(plainPhone)")
        print("Formatted: \(formatPhone(plainPhone))")

        // Remove HTML tags
        func stripHTML(_ html: String) -> String {
            let pattern = "<[^>]+>"
            return html.replacingOccurrences(
                of: pattern,
                with: "",
                options: .regularExpression
            )
        }

        let html = "<p>Hello <b>World</b>!</p>"
        print("\nHTML: \(html)")
        print("Stripped: \(stripHTML(html))")
    }
}

// 6. Text Searching
class RegexSearch {

    static func demonstrateSearch() {
        print("\n--- Regex Search ---")

        let text = """
        Swift is a powerful programming language.
        Swift was developed by Apple for iOS development.
        Many developers love Swift because it's modern and safe.
        """

        // Count occurrences
        func countOccurrences(_ text: String, pattern: String) -> Int {
            do {
                let regex = try NSRegularExpression(pattern: pattern)
                let range = NSRange(text.startIndex..., in: text)
                return regex.numberOfMatches(in: text, range: range)
            } catch {
                return 0
            }
        }

        let swiftCount = countOccurrences(text, pattern: "Swift")
        print("Count of 'Swift': \(swiftCount)")

        // Find all words
        func findAllWords(_ text: String) -> [String] {
            do {
                let pattern = "\\b\\w+\\b"
                let regex = try NSRegularExpression(pattern: pattern)
                let range = NSRange(text.startIndex..., in: text)
                let matches = regex.matches(in: text, range: range)

                return matches.compactMap { match -> String? in
                    if let range = Range(match.range, in: text) {
                        return String(text[range])
                    }
                    return nil
                }
            } catch {
                return []
            }
        }

        let words = findAllWords(text)
        print("\nAll words (\(words.count)): \(words)")

        // Find words starting with capital letter
        func findCapitalizedWords(_ text: String) -> [String] {
            do {
                let pattern = "\\b[A-Z]\\w*\\b"
                let regex = try NSRegularExpression(pattern: pattern)
                let range = NSRange(text.startIndex..., in: text)
                let matches = regex.matches(in: text, range: range)

                return matches.compactMap { match -> String? in
                    if let range = Range(match.range, in: text) {
                        return String(text[range])
                    }
                    return nil
                }
            } catch {
                return []
            }
        }

        let capitalized = findCapitalizedWords(text)
        print("\nCapitalized words: \(capitalized)")

        // Search with case insensitive
        func searchCaseInsensitive(_ text: String, searchTerm: String) -> [NSRange] {
            do {
                let pattern = NSRegularExpression.escapedPattern(for: searchTerm)
                let regex = try NSRegularExpression(pattern: pattern, options: .caseInsensitive)
                let range = NSRange(text.startIndex..., in: text)
                return regex.matches(in: text, range: range).map { $0.range }
            } catch {
                return []
            }
        }

        let searchResults = searchCaseInsensitive(text, searchTerm: "swift")
        print("\nFound 'swift' (case insensitive) at \(searchResults.count) locations")
    }
}

// 7. Advanced Patterns
class AdvancedPatterns {

    static func demonstrateAdvanced() {
        print("\n--- Advanced Patterns ---")

        // IPv4 address validation
        func isValidIP(_ ip: String) -> Bool {
            let pattern = "^((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$"
            let predicate = NSPredicate(format: "SELF MATCHES %@", pattern)
            return predicate.evaluate(with: ip)
        }

        print("IP validation:")
        print("  192.168.1.1: \(isValidIP("192.168.1.1"))")
        print("  256.1.1.1: \(isValidIP("256.1.1.1"))")

        // Credit card pattern (simplified)
        func formatCreditCard(_ number: String) -> String {
            let pattern = "(\\d{4})(\\d{4})(\\d{4})(\\d{4})"
            return number.replacingOccurrences(
                of: pattern,
                with: "$1 $2 $3 $4",
                options: .regularExpression
            )
        }

        let card = "1234567890123456"
        print("\nCredit card: \(formatCreditCard(card))")

        // Hex color code validation
        func isValidHexColor(_ color: String) -> Bool {
            let pattern = "^#([A-Fa-f0-9]{6}|[A-Fa-f0-9]{3})$"
            let predicate = NSPredicate(format: "SELF MATCHES %@", pattern)
            return predicate.evaluate(with: color)
        }

        print("\nHex color validation:")
        print("  #FF0000: \(isValidHexColor("#FF0000"))")
        print("  #FFF: \(isValidHexColor("#FFF"))")
        print("  #GGG: \(isValidHexColor("#GGG"))")

        // Social Security Number (US)
        func isValidSSN(_ ssn: String) -> Bool {
            let pattern = "^(?!000|666)[0-8][0-9]{2}-(?!00)[0-9]{2}-(?!0000)[0-9]{4}$"
            let predicate = NSPredicate(format: "SELF MATCHES %@", pattern)
            return predicate.evaluate(with: ssn)
        }

        print("\nSSN validation:")
        print("  123-45-6789: \(isValidSSN("123-45-6789"))")
        print("  000-00-0000: \(isValidSSN("000-00-0000"))")

        // Date format validation (YYYY-MM-DD)
        func isValidDate(_ date: String) -> Bool {
            let pattern = "^\\d{4}-(0[1-9]|1[0-2])-(0[1-9]|[12][0-9]|3[01])$"
            let predicate = NSPredicate(format: "SELF MATCHES %@", pattern)
            return predicate.evaluate(with: date)
        }

        print("\nDate validation:")
        print("  2024-01-15: \(isValidDate("2024-01-15"))")
        print("  2024-13-01: \(isValidDate("2024-13-01"))")
    }
}

// 8. Regex Options and Flags
class RegexOptions {

    static func demonstrateOptions() {
        print("\n--- Regex Options ---")

        let text = "Hello WORLD. This is a TEST. hello world."

        // Case insensitive
        func findCaseInsensitive(_ text: String, pattern: String) -> Int {
            do {
                let regex = try NSRegularExpression(pattern: pattern, options: .caseInsensitive)
                let range = NSRange(text.startIndex..., in: text)
                return regex.numberOfMatches(in: text, range: range)
            } catch {
                return 0
            }
        }

        print("Case insensitive 'hello': \(findCaseInsensitive(text, pattern: "hello"))")

        // Anchors match line
        let multiline = """
        Line 1 start
        Line 2 start
        Line 3 start
        """

        func countLineStarts(_ text: String) -> Int {
            do {
                let regex = try NSRegularExpression(pattern: "^Line", options: .anchorsMatchLines)
                let range = NSRange(text.startIndex..., in: text)
                return regex.numberOfMatches(in: text, range: range)
            } catch {
                return 0
            }
        }

        print("\nLine starts with 'Line': \(countLineStarts(multiline))")
    }
}

// 9. Performance Tips
class RegexPerformance {

    static func demonstratePerformance() {
        print("\n--- Regex Performance Tips ---")

        // Cache compiled regex
        class RegexCache {
            static var cache: [String: NSRegularExpression] = [:]

            static func get(_ pattern: String) -> NSRegularExpression? {
                if let cached = cache[pattern] {
                    return cached
                }

                do {
                    let regex = try NSRegularExpression(pattern: pattern)
                    cache[pattern] = regex
                    return regex
                } catch {
                    return nil
                }
            }
        }

        // Use cached regex
        func findEmails(_ text: String) -> [String] {
            let pattern = "[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\\.[a-zA-Z]{2,}"

            guard let regex = RegexCache.get(pattern) else {
                return []
            }

            let range = NSRange(text.startIndex..., in: text)
            let matches = regex.matches(in: text, range: range)

            return matches.compactMap { match -> String? in
                if let range = Range(match.range, in: text) {
                    return String(text[range])
                }
                return nil
            }
        }

        let text = "Contact: [email protected] or [email protected]"
        let emails = findEmails(text)
        print("Found emails: \(emails)")

        // Pre-compile for repeated use
        let emailPattern = "[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\\.[a-zA-Z]{2,}"

        do {
            let compiledRegex = try NSRegularExpression(pattern: emailPattern)

            // Use compiled regex multiple times
            for _ in 0..<10 {
                let range = NSRange(text.startIndex..., in: text)
                _ = compiledRegex.matches(in: text, range: range)
            }

            print("Compiled regex used 10 times")

        } catch {
            print("Regex error: \(error)")
        }
    }
}

// 10. Real-World Examples
class RealWorldRegex {

    static func demonstrateRealWorld() {
        print("\n--- Real-World Regex Examples ---")

        // Parse log file format
        let log = "[2024-01-15 10:30:45] ERROR: File not found at /path/to/file.txt"

        func parseLog(_ log: String) -> [String: String] {
            var result: [String: String] = [:]

            // Extract timestamp
            if let timestampRange = log.range(of: "\\\[^\\]+\\]", options: .regularExpression) {
                result["timestamp"] = String(log[timestampRange]).trimmingCharacters(in: CharacterSet(charactersIn: "[]"))
            }

            // Extract log level
            if let levelRange = log.range(of: "(ERROR|WARN|INFO|DEBUG)", options: .regularExpression) {
                result["level"] = String(log[levelRange])
            }

            // Extract message
            if let messageRange = log.range(of: ": .*", options: .regularExpression) {
                result["message"] = String(log[messageRange]).dropFirst(2).description
            }

            return result
        }

        let parsed = parseLog(log)
        print("Parsed log:")
        parsed.forEach { key, value in
            print("  \(key): \(value)")
        }

        // Extract markdown links
        let markdown = "Check [Swift](https://swift.org) and [Apple](https://apple.com)"

        func extractMarkdownLinks(_ text: String) -> [(text: String, url: String)] {
            let pattern = "\\\[([^\\]]+)\\]\\(([^\\)]+)\\)"

            do {
                let regex = try NSRegularExpression(pattern: pattern)
                let range = NSRange(text.startIndex..., in: text)
                let matches = regex.matches(in: text, range: range)

                return matches.compactMap { match -> (String, String)? in
                    guard match.numberOfRanges == 3,
                          let textRange = Range(match.range(at: 1), in: text),
                          let urlRange = Range(match.range(at: 2), in: text) else {
                        return nil
                    }

                    return (String(text[textRange]), String(text[urlRange]))
                }
            } catch {
                return []
            }
        }

        let links = extractMarkdownLinks(markdown)
        print("\nMarkdown links:")
        for link in links {
            print("  [\(link.text)](\(link.url))")
        }
    }
}

// Main demonstration
func demonstrateRegex() {
    print("=== macOS Swift Regular Expression Examples ===")

    BasicRegex.demonstrateBasicMatching()
    NSRegularExpressionExamples.demonstrateNSRegularExpression()
    RegexValidation.demonstrateValidation()
    RegexExtraction.demonstrateExtraction()
    RegexReplacement.demonstrateReplacement()
    RegexSearch.demonstrateSearch()
    AdvancedPatterns.demonstrateAdvanced()
    RegexOptions.demonstrateOptions()
    RegexPerformance.demonstratePerformance()
    RealWorldRegex.demonstrateRealWorld()

    print("\n=== All Regular Expression Examples Completed ===")
}

// Run demonstration
demonstrateRegex()

// macOS Swift String Replacement Examples
// Using Swift standard library

import Foundation

// 1. Basic String Replacement
class BasicReplacement {

    static func demonstrateBasicReplacement() {
        print("\n--- Basic String Replacement ---")

        let text = "Hello World! Welcome to World of programming."

        // Simple replacement
        let replaced = text.replacingOccurrences(of: "World", with: "Swift")
        print("Original: \(text)")
        print("Replaced: \(replaced)")

        // Case sensitive replacement
        let caseSensitive = text.replacingOccurrences(of: "world", with: "Universe")
        print("\nCase sensitive: \(caseSensitive)")

        // Case insensitive replacement
        let caseInsensitive = text.replacingOccurrences(
            of: "world",
            with: "Universe",
            options: .caseInsensitive
        )
        print("Case insensitive: \(caseInsensitive)")

        // Replace first occurrence only
        func replaceFirst(_ text: String, of: String, with: String) -> String {
            guard let range = text.range(of: of) else { return text }
            return text.replacingCharacters(in: range, with: with)
        }

        let firstOnly = replaceFirst(text, of: "World", with: "Swift")
        print("\nReplace first only: \(firstOnly)")
    }
}

// 2. Multiple Replacements
class MultipleReplacements {

    static func demonstrateMultipleReplacements() {
        print("\n--- Multiple Replacements ---")

        let text = "The quick brown fox jumps over the lazy dog."

        // Replace multiple words
        var result = text
        let replacements = [
            ("quick", "slow"),
            ("brown", "white"),
            ("fox", "rabbit")
        ]

        for (old, new) in replacements {
            result = result.replacingOccurrences(of: old, with: new)
        }

        print("Original: \(text)")
        print("After multiple replacements: \(result)")

        // Replace all vowels
        let vowels = "aeiouAEIOU"
        let noVowels = text.unicodeScalars
            .map { vowels.contains(String($0)) ? "*" : String($0) }
            .joined()

        print("\nRemove vowels: \(noVowels)")

        // Chain replacements
        func chainReplace(_ text: String, _ replacements: [(String, String)]) -> String {
            return replacements.reduce(text) { result, replacement in
                result.replacingOccurrences(of: replacement.0, with: replacement.1)
            }
        }

        let chained = chainReplace(text, [
            ("The", "A"),
            ("quick", "fast"),
            ("lazy", "sleeping")
        ])

        print("\nChained replacements: \(chained)")
    }
}

// 3. Regex Replacement
class RegexReplacement {

    static func demonstrateRegexReplacement() {
        print("\n--- Regex Replacement ---")

        // Mask email addresses
        func maskEmails(_ text: String) -> String {
            return text.replacingOccurrences(
                of: "[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\\.[a-zA-Z]{2,}",
                with: "***@***.***",
                options: .regularExpression
            )
        }

        let emails = "Contact [email protected] or [email protected] for help"
        print("Original: \(emails)")
        print("Masked: \(maskEmails(emails))")

        // Remove all numbers
        func removeNumbers(_ text: String) -> String {
            return text.replacingOccurrences(
                of: "\\d+",
                with: "",
                options: .regularExpression
            )
        }

        let withNumbers = "Order #12345 for $67.89 with 10 items"
        print("\nOriginal: \(withNumbers)")
        print("No numbers: \(removeNumbers(withNumbers))")

        // Format currency
        func formatCurrency(_ text: String) -> String {
            return text.replacingOccurrences(
                of: "\\$?(\\d+\\.\\d{2})",
                with: "$$$1",
                options: .regularExpression
            )
        }

        let prices = "Items cost 19.99, 29.99, and 5.50 dollars"
        print("\nOriginal: \(prices)")
        print("Formatted: \(formatCurrency(prices))")

        // Normalize phone numbers
        func normalizePhone(_ text: String) -> String {
            // Remove all non-digits
            let digits = text.replacingOccurrences(
                of: "\\D",
                with: "",
                options: .regularExpression
            )

            // Format as (XXX) XXX-XXXX
            if digits.count == 10 {
                let index1 = digits.index(digits.startIndex, offsetBy: 3)
                let index2 = digits.index(digits.startIndex, offsetBy: 6)

                return "(\(digits[..<index1])) \(digits[index1..<index2])-\(digits[index2...])"
            }

            return digits
        }

        let phones = "Call 123-456-7890 or (987) 654 3210"
        print("\nOriginal: \(phones)")
        print("Normalized: \(normalizePhone(phones))")
    }
}

// 4. Conditional Replacement
class ConditionalReplacement {

    static func demonstrateConditional() {
        print("\n--- Conditional Replacement ---")

        // Replace based on condition
        func replaceIfCondition(_ text: String, predicate: (Character) -> Bool, with: String) -> String {
            return text.map { char in
                predicate(char) ? with : String(char)
            }.joined()
        }

        let text = "Hello123World456"

        let lettersOnly = replaceIfCondition(text) { $0.isNumber }
            .with: ""
        print("Original: \(text)")
        print("Letters only: \(lettersOnly)")

        let numbersAsHash = replaceIfCondition(text) { $0.isNumber }
            .with: "#"
        print("Numbers as #: \(numbersAsHash)")

        // Replace words longer than threshold
        func replaceLongWords(_ text: String, threshold: Int) -> String {
            return text.components(separatedBy: " ").map { word in
                word.count > threshold ? String(repeating: "*", count: word.count) : word
            }.joined(separator: " ")
        }

        let sentence = "The quick brown fox jumps over the lazy dog"
        print("\nOriginal: \(sentence)")
        print("Words > 4 chars masked: \(replaceLongWords(sentence, threshold: 4))")

        // Replace based on context
        func replaceInContext(_ text: String, target: String, replacement: String, context: String) -> String {
            var result = text
            let contextWithTarget = context + " " + target

            result = result.replacingOccurrences(
                of: contextWithTarget,
                with: context + " " + replacement
            )

            return result
        }

        let story = "The red apple. The red ball. The blue car."
        let contextual = replaceInContext(story, target: "red", replacement: "green", context: "The")
        print("\nContextual replacement: \(contextual)")
    }
}

// 5. Batch Replacement with Dictionary
class DictionaryReplacement {

    static func demonstrateDictionaryReplacement() {
        print("\n--- Dictionary Replacement ---")

        let abbreviations = [
            "API": "Application Programming Interface",
            "UI": "User Interface",
            "UX": "User Experience",
            "HTTP": "HyperText Transfer Protocol"
        ]

        let text = "The API uses HTTP to send data to the UI and affects the UX."

        // Replace using dictionary
        func expandAbbreviations(_ text: String, _ abbreviations: [String: String]) -> String {
            var result = text

            for (abbr, expansion) in abbreviations {
                result = result.replacingOccurrences(
                    of: "\\\(abbr)\\b",
                    with: expansion,
                    options: .regularExpression
                )
            }

            return result
        }

        print("Original: \(text)")
        print("Expanded: \(expandAbbreviations(text, abbreviations))")

        // Smart replacement (only whole words)
        func smartReplace(_ text: String, _ replacements: [String: String]) -> String {
            var result = text

            for (from, to) in replacements {
                let pattern = "\\\(from)\\b"
                result = result.replacingOccurrences(
                    of: pattern,
                    with: to,
                    options: .regularExpression
                )
            }

            return result
        }

        let smartText = "cat catalog concatenate"
        let smartReplacements = ["cat": "dog"]
        print("\nOriginal: \(smartText)")
        print("Smart replacement: \(smartReplace(smartText, smartReplacements))")
    }
}

// 6. Template Replacement
class TemplateReplacement {

    static func demonstrateTemplateReplacement() {
        print("\n--- Template Replacement ---")

        // Simple template engine
        func renderTemplate(_ template: String, _ variables: [String: Any]) -> String {
            var result = template

            for (key, value) in variables {
                let placeholder = "{{\(key)}}"
                result = result.replacingOccurrences(of: placeholder, with: "\(value)")
            }

            return result
        }

        let template = """
        Dear {{name}},

        Your order {{orderId}} has been shipped.
        Expected delivery: {{deliveryDate}}

        Thank you for shopping with {{company}}!
        """

        let data: [String: Any] = [
            "name": "John Doe",
            "orderId": "12345",
            "deliveryDate": "2024-01-20",
            "company": "Swift Store"
        ]

        print("Template:")
        print(template)
        print("\nRendered:")
        print(renderTemplate(template, data))

        // Nested template
        func renderNestedTemplate(_ template: String, _ data: [String: Any]) -> String {
            var result = template

            // Handle {{key.nestedKey}}
            func replaceNested(_ match: String) -> String {
                let keyPath = match.dropFirst(2).dropLast(2) // Remove {{ }}
                let parts = keyPath.split(separator: ".")

                var current: Any? = data
                for part in parts {
                    if let dict = current as? [String: Any] {
                        current = dict[String(part)]
                    }
                }

                return "\(current ?? "")"
            }

            let pattern = "\\\{\{[^}]+\\\\}\\}"
            let regex = try? NSRegularExpression(pattern: pattern)
            let range = NSRange(template.startIndex..., in: template)

            if let regex = regex {
                let matches = regex.matches(in: template, range: range).reversed()

                for match in matches {
                    if let matchRange = Range(match.range, in: result) {
                        let matchString = String(result[matchRange])
                        result = result.replacingCharacters(in: matchRange, with: replaceNested(matchString))
                    }
                }
            }

            return result
        }

        let nestedTemplate = "User: {{user.name}}, Email: {{user.email}}"
        let nestedData: [String: Any] = [
            "user": [
                "name": "Alice",
                "email": "[email protected]"
            ]
        ]

        print("\nNested template: \(nestedTemplate)")
        print("Rendered: \(renderNestedTemplate(nestedTemplate, nestedData))")
    }
}

// 7. Range-based Replacement
class RangeReplacement {

    static func demonstrateRangeReplacement() {
        print("\n--- Range-based Replacement ---")

        let text = "Hello World! This is a test string."

        // Replace by index range
        let startIndex = text.index(text.startIndex, offsetBy: 6)
        let endIndex = text.index(text.startIndex, offsetBy: 11)
        let range = startIndex..<endIndex

        let rangeReplaced = text.replacingCharacters(in: range, with: "Swift")
        print("Original: \(text)")
        print("Replaced chars 6-11: \(rangeReplaced)")

        // Replace first N characters
        func replaceFirstN(_ text: String, n: Int, with: String) -> String {
            let endIndex = text.index(text.startIndex, offsetBy: min(n, text.count))
            return text.replacingCharacters(in: text.startIndex..<endIndex, with: with)
        }

        let first5Replaced = replaceFirstN(text, n: 5, with: "Hi")
        print("\nReplace first 5: \(first5Replaced)")

        // Replace last N characters
        func replaceLastN(_ text: String, n: Int, with: String) -> String {
            let startIndex = text.index(text.endIndex, offsetBy: -min(n, text.count))
            return text.replacingCharacters(in: startIndex..<text.endIndex, with: with)
        }

        let last7Replaced = replaceLastN(text, n: 7, with: "done.")
        print("\nReplace last 7: \(last7Replaced)")

        // Replace between two strings
        func replaceBetween(_ text: String, from: String, to: String, with: String) -> String {
            guard let fromRange = text.range(of: from),
                  let toRange = text.range(of: to, range: fromRange.upperBound..<text.endIndex) else {
                return text
            }

            let replaceRange = fromRange.upperBound..<toRange.lowerBound
            return text.replacingCharacters(in: replaceRange, with: with)
        }

        let markers = "START [content to replace] END"
        let betweenReplaced = replaceBetween(markers, from: "START", to: "END", with: "NEW CONTENT")
        print("\nReplace between markers: \(betweenReplaced)")
    }
}

// 8. Transliteration
class Transliteration {

    static func demonstrateTransliteration() {
        print("\n--- Transliteration ---")

        // Character mapping
        func transliterate(_ text: String, _ mapping: [Character: String]) -> String {
            return text.map { char in
                mapping[char, default: String(char)]
            }.joined()
        }

        let leetSpeak: [Character: String] = [
            "a": "4",
            "e": "3",
            "i": "1",
            "o": "0",
            "s": "5",
            "t": "7"
        ]

        let normal = "Hello elite hackers"
        let leet = transliterate(normal.lowercased(), leetSpeak)
        print("Normal: \(normal)")
        print("Leet speak: \(leet)")

        // ROT13
        func rot13(_ text: String) -> String {
            return text.map { char in
                if char.isLetter {
                    let base = char.isUppercase ? Character("A") : Character("a")
                    let offset = (char.asciiValue! - base.asciiValue! + 13) % 26
                    return Character(UnicodeScalar(base.asciiValue! + offset))
                }
                return char
            }.joined()
        }

        let secret = "Hello World"
        let encoded = rot13(secret)
        print("\nOriginal: \(secret)")
        print("ROT13: \(encoded)")
        print("Decoded: \(rot13(encoded))")

        // To lowercase/uppercase
        func toggleCase(_ text: String) -> String {
            return text.map { char in
                char.isUppercase ? char.lowercased() : char.uppercased()
            }.joined()
        }

        let mixed = "HeLLo WoRLd"
        print("\nOriginal: \(mixed)")
        print("Toggled case: \(toggleCase(mixed))")
    }
}

// 9. Text Cleanup
class TextCleanup {

    static func demonstrateCleanup() {
        print("\n--- Text Cleanup ---")

        // Remove extra whitespace
        func cleanWhitespace(_ text: String) -> String {
            let collapsed = text.replacingOccurrences(
                of: "\\s+",
                with: " ",
                options: .regularExpression
            )
            return collapsed.trimmingCharacters(in: .whitespacesAndNewlines)
        }

        let messy = "  Hello    world   from   Swift  \n\n  "
        print("Original: '\(messy)'")
        print("Cleaned: '\(cleanWhitespace(messy))'")

        // Remove special characters
        func cleanSpecialChars(_ text: String, keep: String = "") -> String {
            var allowed = CharacterSet.alphanumerics
            allowed.insert(charactersIn: " \n\t" + keep)

            return text.components(separatedBy: allowed.inverted)
                .joined()
        }

        let special = "Hello! @World #123 $Test"
        print("\nOriginal: \(special)")
        print("Keep alphanumeric: \(cleanSpecialChars(special))")
        print("Keep alphanumeric + #: \(cleanSpecialChars(special, keep: "#"))")

        // Normalize line endings
        func normalizeLineEndings(_ text: String) -> String {
            return text.replacingOccurrences(
                of: "\\r\\n|\\r",
                with: "\n",
                options: .regularExpression
            )
        }

        let mixedEndings = "Line1\r\nLine2\rLine3\nLine4"
        print("\nMixed line endings normalized:")
        print(normalizeLineEndings(mixedEndings))

        // Remove duplicate lines
        func removeDuplicateLines(_ text: String) -> String {
            let lines = text.components(separatedBy: "\n")
            let unique = Array(Set(lines))
            return unique.joined(separator: "\n")
        }

        let dupLines = """
        Line 1
        Line 2
        Line 1
        Line 3
        Line 2
        """

        print("\nOriginal with duplicates:")
        print(removeDuplicateLines(dupLines))
    }
}

// 10. Smart Replacement
class SmartReplacement {

    static func demonstrateSmartReplacement() {
        print("\n--- Smart Replacement ---")

        // Avoid replacing already replaced
        func replaceWithoutDuplicates(_ text: String, target: String, replacement: String) -> String {
            var result = text
            var replacedRanges: [Range<String.Index>] = []

            while let range = result.range(of: target) {
                // Check if this range overlaps with already replaced
                let overlaps = replacedRanges.contains { replacedRange in
                    !(range.upperBound < replacedRange.lowerBound || range.lowerBound > replacedRange.upperBound)
                }

                if !overlaps {
                    result = result.replacingCharacters(in: range, with: replacement)
                    let newRange = result.range(of: replacement, range: range)
                    if let newRange = newRange {
                        replacedRanges.append(newRange)
                    }
                }

                // Continue search after this range
                let searchStart = result.index(after: range.upperBound)
                guard searchStart < result.endIndex else { break }
            }

            return result
        }

        let overlapText = "test testest"
        print("Original: \(overlapText)")
        print("Smart replace 'test' with 'X': \(replaceWithoutDuplicates(overlapText, target: "test", replacement: "X"))")

        // Preserve case
        func replacePreservingCase(_ text: String, target: String, replacement: String) -> String {
            let pattern = NSRegularExpression.escapedPattern(for: target)

            do {
                let regex = try NSRegularExpression(pattern: pattern, options: .caseInsensitive)
                let range = NSRange(text.startIndex..., in: text)

                let result = regex.stringByReplacingMatches(
                    in: text,
                    options: [],
                    range: range,
                    withTemplate: replacement
                )

                // Fix case (simplified - real implementation would need more sophisticated logic)
                return result

            } catch {
                return text
            }
        }

        let caseText = "The TEST and Test are in test"
        print("\nOriginal: \(caseText)")
        print("Replace 'test' with 'example': \(replacePreservingCase(caseText, target: "test", replacement: "example"))")
    }
}

// Main demonstration
func demonstrateStringReplacement() {
    print("=== macOS Swift String Replacement Examples ===")

    BasicReplacement.demonstrateBasicReplacement()
    MultipleReplacements.demonstrateMultipleReplacements()
    RegexReplacement.demonstrateRegexReplacement()
    ConditionalReplacement.demonstrateConditional()
    DictionaryReplacement.demonstrateDictionaryReplacement()
    TemplateReplacement.demonstrateTemplateReplacement()
    RangeReplacement.demonstrateRangeReplacement()
    Transliteration.demonstrateTransliteration()
    TextCleanup.demonstrateCleanup()
    SmartReplacement.demonstrateSmartReplacement()

    print("\n=== All String Replacement Examples Completed ===")
}

// Run demonstration
demonstrateStringReplacement()