add hash, dropFirst and dropLast.

README.md

@@ -490,6 +490,9 @@ Although not visible when writing templates, each underlying value that is passe
 
 * `String`:
   * `capitalized() -> String`: Capitalizes the first letter.
+  * `dropFirst() -> String`: Equivalent to Swift's `.dropFirst()`.
+  * `dropLast() -> String`: Equivalent to Swift's `.dropLast()`.
+  * `hash() -> String`: The hash of the string using the `CRC32` algorithm.
   * `snakeCased() -> String`: Converts the string from camelCase to snake_case.
   * `camelCased() -> String`: Converts the string from snake_case to camelCase.
   * `withParens() -> String`: If the string is not empty, surrounds it in parenthesis.
@@ -499,27 +502,28 @@ Although not visible when writing templates, each underlying value that is passe
   * `equalsZero() -> Bool`: Returns whether the integer is equal to zero.
   * `isOdd() -> Bool`: Returns whether the integer is odd or not.
   * `isEven() -> Bool`: Returns whether the integer is even or not.
+  * `hash() -> String`: The hash of the string representation of the integer using the `CRC32` algorithm.
 * `Array`:
   * `first() -> Element?`: Returns the first element of the array.
   * `last() -> Element?`: Returns the last element of the array.
   * `count() -> Int`:  Returns the number of the elements in the array.
   * `isEmpty() -> Bool`: Returns whether the array is empty or not.
   * `reversed() -> Self`: Returns a reversed array.
   * `sorted() -> Self`: Sorts the elements, if the elements of the array are comparable.
-  * `joined() -> String`: Equivalent to `.joined(separator: ", ")`
+  * `joined() -> String`: Equivalent to Swift's `.joined(separator: ", ")`.
   * `keyValues() -> [KeyValue]`: Parses the elements of the array as key-value pairs separated by ':'.
 * `Optional`:
   * `exists() -> Bool`: Returns whether this optional value contains anything.
   * `isEmpty() -> Bool`: Returns whether this optional value contains anything.
     * If a value exists, the call will be forwarded to that.
-    * For example `Optional<String>.some("")` will return `true` for `isEmpty` becasue although the optional exists, the string value is empty.
+    * For example `Optional<String>.some("")` will return `true` for `isEmpty` because although the optional exists, the string value is empty.
   * `Optional` is a see-through value like in Swift. You can use any functions that are available for the wrapperd type, when you're sure the value exists.
 * `KeyValue`:
   * `key() -> String`: Returns the key. You could use Mustache-native {{key}} syntax as well.
   * `value() -> String`: Returns the value. You could use Mustache-native {{value}} syntax as well.
 * `[KeyValue]` (`comments`):
   * All `Array` functions are applicable to `[KeyValue]` as well.
-  * Imagine a `[KeyValue]` as a `Dictonary<String, String>`.
+  * Imagine a `[KeyValue]` as a `Dictionary<String, String>`.
   * You can use function names as a way of subscripting.
   * For example `business_error(myKeyValues)` will find an element in `myKeyValues` where `key` == `business_error`, and will return the `value` as an `String?`.
 * `[Parameter]` (`parameters`):

Sources/EnumeratorMacro/Enumerator.swift

@@ -6,3 +6,141 @@ public macro Enumerator(
     module: "EnumeratorMacroImpl",
     type: "EnumeratorMacroType"
 )
+
+@Enumerator("""
+var caseName: String {
+    switch self {
+    {{#cases}}
+    case .{{name}}: "{{#first(parameters)}} {{name}} {{/first(parameters)}}"
+    {{/cases}}
+    }
+}
+""")
+enum TestEnum {
+    case a(val1: String, val2: Int)
+    case b
+    case testCase(testValue: String)
+}
+
+public protocol LocalizationServiceProtocol {
+    static func localizedString(language: String, term: String, parameters: Any...) -> String
+}
+
+package enum SharedConfiguration {
+    package enum Env: String {
+        case local
+        case testing
+        case prod
+    }
+
+    package static var env: Env { fatalError() }
+}
+
+@Enumerator(allowedComments: ["business_error", "l8n_params"],
+"""
+public enum Subtype: String, Equatable {
+    {{#cases}}
+    case {{name}}
+    {{/cases}}
+}
+""",
+"""
+public var subtype: Subtype {
+    switch self {
+    {{#cases}}
+    case .{{name}}:
+        .{{name}}
+    {{/cases}}
+    }
+}
+""",
+"""
+public var errorCode: String {
+    switch self {
+    {{#cases}}
+    case .{{name}}:
+        "ERROR-{{plusOne(index)}}"
+    {{/cases}}
+    }
+}
+""",
+"""
+public var loggerMetadata: [String: String] {
+    switch self {
+    {{#cases}} {{^isEmpty(parameters)}}
+    case let .{{name}}{{withParens(joined(names(parameters)))}}:
+        [
+            "caseName": self.caseName,
+            {{#names(parameters)}}
+            "case_{{.}}": String(reflecting: {{.}}),
+            {{/names(parameters)}}
+        ]
+    {{/isEmpty(parameters)}} {{/cases}}
+    default:
+        ["caseName": self.caseName]
+    }
+}
+""",
+"""
+private var localizationParameters: [Any] {
+    switch self {
+    {{#cases}} {{^isEmpty(parameters)}}
+
+    {{^isEmpty(l8n_params(comments))}}
+    case let .{{name}}{{withParens(joined(names(parameters)))}}:
+        [{{l8n_params(comments)}}]
+    {{/isEmpty(l8n_params(comments))}}
+
+    {{^exists(l8n_params(comments))}}
+    case let .{{name}}{{withParens(joined(names(parameters)))}}:
+    [
+        {{#parameters}}
+        {{name}}{{#isOptional}} as Any{{/isOptional}},
+        {{/parameters}}
+    ]
+    {{/exists(l8n_params(comments))}}
+
+    {{/isEmpty(parameters)}} {{/cases}}
+    default:
+        []
+    }
+}
+""")
+@Enumerator(
+    allowedComments: ["business_error", "l8n_params"],
+    #"""
+    package var isBusinessLogicError: Bool {
+        switch self {
+        case
+        {{#cases}}{{#bool(business_error(comments))}}
+        .{{name}},
+        {{/bool(business_error(comments))}}{{/cases}}
+        :
+            return true
+        default:
+            return false
+        }
+    }
+    """#
+)
+public enum ErrorMessage {
+    public static let localizationServiceType: LocalizationServiceProtocol.Type? = nil
+
+    case allergenAlreadyAdded // business_error
+    case alreadyOngoingInventory
+    case apiKeyWithoutEnoughPermission(integration: String, other: Bool?, Int)
+    case databaseError(error: Error, isConstraintViolation: Bool) // business_error; l8n_params:
+
+    public var caseName: String {
+        self.subtype.rawValue
+    }
+
+    public func toString(_ language: String) -> String {
+        let translation = Self.localizationServiceType?.localizedString(
+            language: language,
+            term: "api.\(self.caseName)",
+            parameters: self.localizationParameters
+        )
+        return translation ?? (SharedConfiguration.env == .testing ? String(reflecting: self) : "<localization failed to load for \(self.caseName)>")
+    }
+}

Sources/EnumeratorMacroImpl/Types/CRC32.swift

@@ -0,0 +1,74 @@
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2023 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for Swift project authors
+//
+
+/// The precomputed CRC-32 lookup table.
+///
+/// This table is used by the ``crc32(_:)`` function below. It is borrowed from
+/// the [Swift standard library](https://github.com/swiftlang/swift/blob/main/stdlib/public/Backtracing/Elf.swift).
+private let _crc32Table: [UInt32] = [
+    0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
+    0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
+    0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
+    0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
+    0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
+    0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
+    0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c,
+    0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
+    0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
+    0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
+    0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, 0x01db7106,
+    0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
+    0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d,
+    0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
+    0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
+    0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
+    0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7,
+    0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
+    0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa,
+    0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
+    0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
+    0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
+    0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84,
+    0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
+    0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
+    0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
+    0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
+    0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
+    0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55,
+    0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
+    0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28,
+    0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
+    0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
+    0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
+    0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
+    0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
+    0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69,
+    0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
+    0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
+    0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
+    0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693,
+    0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
+    0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
+]
+
+/// Compute the CRC-32 code for a sequence of bytes.
+///
+/// - Parameters:
+///   - bytes: The bytes for which a CRC-32 code should be computed.
+///
+/// - Returns: The CRC-32 code computed for `bytes`.
+///
+/// A starting value of `0` is assumed. This function is adapted from the
+/// [Swift standard library](https://github.com/swiftlang/swift/blob/main/stdlib/public/Backtracing/Elf.swift).
+func crc32(_ bytes: some Sequence<UInt8>) -> UInt32 {
+    ~bytes.reduce(~0) { crcValue, byte in
+        _crc32Table[Int(UInt8(truncatingIfNeeded: crcValue) ^ byte)] ^ (crcValue >> 8)
+    }
+}

Sources/EnumeratorMacroImpl/Types/EInt.swift

@@ -43,6 +43,8 @@ extension EInt: EMustacheTransformable {
             return (self.underlying & 1) == 0
         case "isOdd":
             return (self.underlying & 1) == 1
+        case "hash":
+            return EString(crc32(self.description.utf8).description)
         default:
             RenderingContext.current.addOrReplaceFunctionDiagnostic(
                 .invalidTransform(

Sources/EnumeratorMacroImpl/Types/EString.swift

@@ -51,6 +51,12 @@ extension EString: EMustacheTransformable {
             return self.isEmpty ? self : "(\(self))"
         case "bool":
             return Bool(self)
+        case "hash":
+            return EString(crc32(self.utf8).description)
+        case "dropFirst":
+            return EString(String(self.dropFirst()))
+        case "dropLast":
+            return EString(String(self.dropLast()))
         case "keyValue":
             return EKeyValue(from: self.underlying)
         default:

Sources/EnumeratorMacroImpl/Visitors/ExcessiveTriviaRemover.swift

@@ -49,8 +49,8 @@ final class ExcessiveTriviaRemover: SyntaxRewriter {
             /// Combine consecutive `newlines` into a single one.
             pieces = pieces.reduce(into: [TriviaPiece]()) { result, next in
                 if case let .newlines(countNext) = next,
-                   let last = result.last,
-                   case let .newlines(countLast) = last {
+                   let previous = result.last,
+                   case let .newlines(countLast) = previous {
                     result[result.count - 1] = .newlines(countNext + countLast)
                 } else {
                     result.append(next)

Tests/EnumeratorMacroTests/EnumeratorMacroTests.swift

@@ -45,6 +45,45 @@ final class EnumeratorMacroTests: XCTestCase {
         )
     }
 
+    func testCreatesCaseCods() {
+        assertMacroExpansion(
+            #"""
+            @Enumerator(
+            """
+            var caseCode: Int {
+                switch self {
+                {{#cases}}
+                case .{{name}}:
+                    {{dropLast(dropLast(dropLast(dropLast(dropLast(hash(name))))))}}
+                {{/cases}}
+                }
+            }
+            """
+            )
+            enum TestEnum {
+                case aBcD
+                case eFgH
+            }
+            """#,
+            expandedSource: #"""
+            enum TestEnum {
+                case aBcD
+                case eFgH
+            
+                var caseCode: Int {
+                    switch self {
+                    case .aBcD:
+                        40035
+                    case .eFgH:
+                        1856
+                    }
+                }
+            }
+            """#,
+            macros: EnumeratorMacroEntryPoint.macros
+        )
+    }
+
     func testCreatesACopyOfSelf() {
         assertMacroExpansion(
             #"""