Ability to have other enum rawValue parser

[ytyubox]

Hi, I would like to have my enum be a Parse. I have learned that we can use RawValue and CaseIterable on the enum type to gain the Parse for free.

enum Person: Int, CaseIterable {
      case blob = 4
      case blobJr = 42
}

For some reason, I would like to have my Parser adopt UInt8 enum, But I found that it is not achievable.

enum Format: UInt8, CaseIterable {
      case ascii = 0x1
      case unicode = 0x2
}

For any enumeration with a string, integer, or floating-point raw type, the Swift compiler automatically adds RawRepresentable conformance.

• RawRepresentable | Apple Developer Documentation,

IMO, I have simple way for me is to extend CaseIterable && RawRepresentable && UInt8, like CaseIterableRawRepresentable.swift in a3d52c6

swift-parsing/Sources/Parsing/ParserPrinters/CaseIterableRawRepresentable.swift

Lines 1 to 16 in a3d52c6

	extension CaseIterable where Self: RawRepresentable, RawValue == Int {
	/// A parser that consumes a case-iterable, raw representable value from the beginning of a
	/// collection of a substring.
	///
	/// See <doc:CaseIterable> for more info.
	///
	/// - Parameter inputType: The `Substring` type. This parameter is included to mirror the
	/// interface that parses any collection of UTF-8 code units.
	/// - Returns: A parser that consumes a case-iterable, raw representable value from the beginning
	/// of a substring.
	@inlinable
	public static func parser(
	of inputType: Substring.Type = Substring.self
	) -> Parsers.CaseIterableRawRepresentableParser<Substring, Self, String> {
	.init(toPrefix: { String($0) }, areEquivalent: ==)
	}

Then, I found that Parsers.CaseIterableRawRepresentableParser is public, but its init is internal 😞

Therefore, I would like to propose making Parsers.CaseIterableRawRepresentableParser.init public!

The patch is quite simple as follows.

diff --git a/Sources/Parsing/ParserPrinters/CaseIterableRawRepresentable.swift b/Sources/Parsing/ParserPrinters/CaseIterableRawRepresentable.swift
index f401edd5a..3336cac0e 100644
--- a/Sources/Parsing/ParserPrinters/CaseIterableRawRepresentable.swift
+++ b/Sources/Parsing/ParserPrinters/CaseIterableRawRepresentable.swift
@@ -118,8 +118,7 @@ extension Parsers {
     @usableFromInline
     let cases: [(case: Output, prefix: Prefix, count: Int)]
 
-    @usableFromInline
-    init(
+    public init(
       toPrefix: @escaping (Output.RawValue) -> Prefix,
       areEquivalent: @escaping (Input.Element, Input.Element) -> Bool
     ) {

[mbrandonw]

Hi @ytyubox, good catch!

Rather than making the initializer public, what if we made the parser work with all FixedWidthInteger types? Then we could all the various integer types.

If you have the time you want to open a PR to do that? If not we can take care of it.

[ytyubox]

Sure, here you go.#277

[ytyubox]

Hi, @mbrandonw can you please take a look?

[mbrandonw]

Hi @ytyubox, thanks for following up. Just merged!