refactor: start is non-nullable, but defaults to 1

Author: QuietMisdreavus

Sources/Markdown/Base/RawMarkup.swift

@@ -24,7 +24,7 @@ enum RawMarkupData: Equatable {
     case thematicBreak
     case htmlBlock(String)
     case listItem(checkbox: Checkbox?)
-    case orderedList(start: Int?)
+    case orderedList(start: Int = 1)
     case unorderedList
     case paragraph
     case blockDirective(name: String, nameLocation: SourceLocation?, arguments: DirectiveArgumentText)
@@ -217,7 +217,7 @@ final class RawMarkup: ManagedBuffer<RawMarkupHeader, RawMarkup> {
         return .create(data: .listItem(checkbox: checkbox), parsedRange: parsedRange, children: children)
     }
 
-    static func orderedList(parsedRange: SourceRange?, _ children: [RawMarkup], start: Int?) -> RawMarkup {
+    static func orderedList(parsedRange: SourceRange?, _ children: [RawMarkup], start: Int = 1) -> RawMarkup {
         return .create(data: .orderedList(start: start), parsedRange: parsedRange, children: children)
     }
 

Sources/Markdown/Block Nodes/Block Container Blocks/OrderedList.swift

@@ -29,21 +29,21 @@ public extension OrderedList {
     // MARK: ListItemContainer
 
     init<Items: Sequence>(_ items: Items) where Items.Element == ListItem {
-        try! self.init(.orderedList(parsedRange: nil, items.map { $0.raw.markup }, start: nil))
+        try! self.init(.orderedList(parsedRange: nil, items.map { $0.raw.markup }))
     }
 
     /// The starting index for the list.
     ///
-    /// If this is `nil`, the list will start at the default value of 1.
-    var start: Int? {
+    /// The default starting index in CommonMark is 1. In this case, clients may use any desired index for this list.
+    var start: Int {
         get {
             guard case let .orderedList(start) = _data.raw.markup.data else {
                 fatalError("\(self) markup wrapped unexpected \(_data.raw)")
             }
             return start
         }
         set {
-            precondition(newValue ?? 1 > 0, "List start must be 1 or greater")
+            precondition(newValue > 0, "List start must be 1 or greater")
             guard start != newValue else {
                 return
             }

Sources/Markdown/Parser/CommonMarkConverter.swift

@@ -299,9 +299,8 @@ struct MarkupParser {
         case CMARK_BULLET_LIST:
             return MarkupConversion(state: childConversion.state.next(), result: .unorderedList(parsedRange: parsedRange, childConversion.result))
         case CMARK_ORDERED_LIST:
-            let cmarkStart = cmark_node_get_list_start(state.node)
-            let start: Int? = cmarkStart == 1 ? nil : Int(cmarkStart)
-            return MarkupConversion(state: childConversion.state.next(), result: .orderedList(parsedRange: parsedRange, childConversion.result, start: start))
+            let cmarkStart = Int(cmark_node_get_list_start(state.node))
+            return MarkupConversion(state: childConversion.state.next(), result: .orderedList(parsedRange: parsedRange, childConversion.result, start: cmarkStart))
         default:
             fatalError("cmark reported a list node but said its list type is CMARK_NO_LIST?")
         }

Sources/Markdown/Walker/Walkers/MarkupFormatter.swift

@@ -498,14 +498,14 @@ public struct MarkupFormatter: MarkupWalker {
         let numeral: UInt
         switch formattingOptions.orderedListNumerals {
         case let .allSame(n):
-            if let origStart = list.start {
-                numeral = UInt(origStart)
-            } else {
+            if list.start == 1 {
                 numeral = n
+            } else {
+                numeral = UInt(list.start)
             }
         case let .incrementing(start):
-            if let origStart = list.start {
-                numeral = UInt(origStart) + UInt(listItem.indexInParent)
+            if list.start != 1 {
+                numeral = UInt(list.start) + UInt(listItem.indexInParent)
             } else {
                 numeral = start + UInt(listItem.indexInParent)
             }

Sources/Markdown/Walker/Walkers/MarkupTreeDumper.swift

@@ -190,8 +190,8 @@ struct MarkupTreeDumper: MarkupWalker {
     }
 
     mutating func visitOrderedList(_ orderedList: OrderedList) {
-        if let start = orderedList.start {
-            dump(orderedList, customDescription: "start: \(start)")
+        if orderedList.start != 1 {
+            dump(orderedList, customDescription: "start: \(orderedList.start)")
         } else {
             defaultVisit(orderedList)
         }

Tests/MarkdownTests/Base/RawMarkupToMarkupTests.swift

@@ -48,7 +48,7 @@ final class RawMarkupToMarkupTests: XCTestCase {
     }
 
     func testOrderedList() {
-        XCTAssertNoThrow(try OrderedList(.orderedList(parsedRange: nil, [], start: nil)))
+        XCTAssertNoThrow(try OrderedList(.orderedList(parsedRange: nil, [])))
         XCTAssertThrowsError(try OrderedList(.softBreak(parsedRange: nil)))
     }