feat: add postal code validation rule

README.md

@@ -316,6 +316,7 @@ struct RegistrationView: View {
 | `ComparisonValidationRule` | Validates that input against a comparison constraint | `ComparisonValidationRule(greaterThan: 0, error: "Must be greater than 0")`
 | `IBANValidationRule` | Validates that a string is a valid IBAN (International Bank Account Number) | `IBANValidationRule(error: "Invalid IBAN")`
 | `IPAddressValidationRule` | Validates that a string is a valid IPv4 or IPv6 address | `IPAddressValidationRule(version: .v4, error: ValidationError("Invalid IPv4"))`
+| `PostalCodeValidationRule` | Validates postal/ZIP codes for different countries | `PostalCodeValidationRule(country: .uk, error: "Invalid post code")`
 
 ## Custom Validators
 

Sources/ValidatorCore/Classes/Rules/PostalCodeValidationRule.swift

@@ -0,0 +1,218 @@
+//
+// Validator
+// Copyright © 2025 Space Code. All rights reserved.
+//
+
+import Foundation
+
+// MARK: - PostalCodeValidationRule
+
+/// A validation rule used to verify postal/ZIP codes for different countries.
+///
+/// `PostalCodeValidationRule` validates user input based on predefined
+/// country-specific postal code formats using regular expressions.
+///
+/// # Example:
+/// ```swift
+/// let rule = PostalCodeValidationRule(country: .uk, error: "Invalid postal code")
+/// rule.validate(input: "SW1A 1AA") // true
+/// rule.validate(input: "123456") // false
+/// ```
+///
+public struct PostalCodeValidationRule: IValidationRule {
+    // MARK: Types
+
+    // swiftlint:disable identifier_name
+    /// Supported countries with unique postal code formats.
+    public enum Country {
+        case us
+        case uk
+        case ca
+        case de
+        case fr
+        case it
+        case es
+        case nl
+        case be
+        case ch
+        case at
+        case au
+        case nz
+        case jp
+        case cn
+        case `in`
+        case br
+        case mx
+        case ar
+        case za
+        case ru
+        case pl
+        case se
+        case no
+        case dk
+        case fi
+        case pt
+        case gr
+        case cz
+        case ie
+        case sg
+        case kr
+        case il
+        case tr
+    }
+
+    // swiftlint:enable identifier_name
+
+    // MARK: Properties
+
+    /// The country format to validate against.
+    public let country: Country
+
+    /// Validation error returned when validation fails.
+    public let error: IValidationError
+
+    // MARK: Initialization
+
+    /// Creates a new postal code validation rule.
+    ///
+    /// - Parameters:
+    ///   - country: The country whose postal code format should be used.
+    ///   - error: Error object returned when validation fails.
+    public init(country: Country, error: IValidationError) {
+        self.country = country
+        self.error = error
+    }
+
+    // MARK: ValidationRule
+
+    public func validate(input: String) -> Bool {
+        let trimmedInput = input.trimmingCharacters(in: .whitespacesAndNewlines)
+
+        if trimmedInput.isEmpty {
+            return false
+        }
+
+        if input != trimmedInput {
+            return false
+        }
+
+        let pattern = getPattern(for: country)
+
+        guard let regex = try? NSRegularExpression(pattern: pattern, options: []) else {
+            return false
+        }
+
+        let range = NSRange(location: 0, length: input.utf16.count)
+        return regex.firstMatch(in: input, options: [], range: range) != nil
+    }
+
+    // MARK: Private Methods
+
+    // swiftlint:disable function_body_length cyclomatic_complexity
+    private func getPattern(for country: Country) -> String {
+        switch country {
+        case .us:
+            #"^\d{5}(-\d{4})?$"#
+
+        case .ca:
+            #"^[ABCEGHJ-NPRSTVXY]\d[ABCEGHJ-NPRSTV-Z] \d[ABCEGHJ-NPRSTV-Z]\d$"#
+
+        case .mx:
+            #"^\d{5}$"#
+
+        case .br:
+            #"^\d{5}-\d{3}$"#
+
+        case .ar:
+            #"^([A-Z]\d{4}([A-Z]{3})?|\d{4})$"#
+
+        case .uk:
+            #"^[A-Z]{1,2}\d[A-Z\d]? ?\d[A-Z]{2}$"#
+
+        case .de:
+            #"^\d{5}$"#
+
+        case .fr:
+            #"^\d{5}$"#
+
+        case .it:
+            #"^\d{5}$"#
+
+        case .es:
+            #"^\d{5}$"#
+
+        case .nl:
+            #"^\d{4} [A-Z]{2}$"#
+
+        case .be:
+            #"^\d{4}$"#
+
+        case .ch:
+            #"^\d{4}$"#
+
+        case .at:
+            #"^\d{4}$"#
+
+        case .pt:
+            #"^\d{4}-\d{3}$"#
+
+        case .gr:
+            #"^\d{3} \d{2}$"#
+
+        case .ie:
+            #"^[A-Z]\d{2} [A-Z0-9]{4}$"#
+
+        case .se:
+            #"^\d{3} \d{2}$"#
+
+        case .no:
+            #"^\d{4}$"#
+
+        case .dk:
+            #"^\d{4}$"#
+
+        case .fi:
+            #"^\d{5}$"#
+
+        case .ru:
+            #"^\d{6}$"#
+
+        case .pl:
+            #"^\d{2}-\d{3}$"#
+
+        case .cz:
+            #"^\d{3} \d{2}$"#
+
+        case .jp:
+            #"^\d{3}-\d{4}$"#
+
+        case .cn:
+            #"^\d{6}$"#
+
+        case .in:
+            #"^\d{6}$"#
+
+        case .sg:
+            #"^\d{6}$"#
+
+        case .kr:
+            #"^\d{5}$"#
+
+        case .il:
+            #"^\d{7}$"#
+
+        case .tr:
+            #"^\d{5}$"#
+
+        case .au:
+            #"^\d{4}$"#
+
+        case .nz:
+            #"^\d{4}$"#
+
+        case .za:
+            #"^\d{4}$"#
+        }
+    }
+    // swiftlint:enable function_body_length cyclomatic_complexity
+}

Sources/ValidatorCore/Validator.docc/Overview.md

@@ -39,6 +39,7 @@ ValidatorCore contains all core validation rules, utilities, and mechanisms for
 - ``ComparisonValidationRule``
 - ``IBANValidationRule``
 - ``IPAddressValidationRule``
+- ``PostalCodeValidationRule``
 
 ### Articles