Implement structured Markdown table parsing

Sources/SwiftParser/Languages/MarkdownLanguage.swift

@@ -22,6 +22,9 @@ public struct MarkdownLanguage: CodeLanguage {
         case entity
         case strikethrough
         case table
+        case tableHeader
+        case tableRow
+        case tableCell
         case autoLink
         case linkReferenceDefinition
     }
@@ -1045,10 +1048,10 @@ public struct MarkdownLanguage: CodeLanguage {
             }
             return false
         }
-        public func build(context: inout CodeContext) {
+        func parseRow(_ context: inout CodeContext) -> [String] {
             var cells: [String] = []
             var cell = ""
-            context.index += 1 // skip first pipe
+            context.index += 1 // skip leading pipe
             while context.index < context.tokens.count {
                 if let tok = context.tokens[context.index] as? Token {
                     switch tok {
@@ -1060,8 +1063,7 @@ public struct MarkdownLanguage: CodeLanguage {
                         cells.append(cell.trimmingCharacters(in: .whitespaces))
                         if let last = cells.last, last.isEmpty { cells.removeLast() }
                         context.index += 1
-                        context.currentNode.addChild(MarkdownTableNode(value: cells.joined(separator: "|")))
-                        return
+                        return cells
                     default:
                         cell += tok.text
                         context.index += 1
@@ -1072,7 +1074,64 @@ public struct MarkdownLanguage: CodeLanguage {
             }
             if !cell.isEmpty || !cells.isEmpty {
                 cells.append(cell.trimmingCharacters(in: .whitespaces))
-                context.currentNode.addChild(MarkdownTableNode(value: cells.joined(separator: "|")))
+            }
+            return cells
+        }
+
+        func parseDelimiter(_ context: inout CodeContext) -> [String]? {
+            guard context.index < context.tokens.count,
+                  let first = context.tokens[context.index] as? Token,
+                  case .pipe = first else { return nil }
+            var snapshot = context.snapshot()
+            let cells = parseRow(&context)
+            for cell in cells {
+                var trimmed = cell.trimmingCharacters(in: .whitespaces)
+                if trimmed.hasPrefix(":") { trimmed.removeFirst() }
+                if trimmed.hasSuffix(":") { trimmed.removeLast() }
+                if trimmed.count < 3 { context.restore(snapshot); return nil }
+                if !trimmed.allSatisfy({ $0 == "-" }) {
+                    context.restore(snapshot); return nil
+                }
+            }
+            return cells
+        }
+
+        public func build(context: inout CodeContext) {
+            var ctx = context
+            let header = parseRow(&ctx)
+            let startIndex = ctx.index
+            if let _ = parseDelimiter(&ctx) {
+                var rows: [[String]] = []
+                while ctx.index < ctx.tokens.count,
+                      let tok = ctx.tokens[ctx.index] as? Token,
+                      case .pipe = tok {
+                    rows.append(parseRow(&ctx))
+                }
+
+                let table = MarkdownTableNode()
+                let headerNode = MarkdownTableHeaderNode()
+                for cell in header {
+                    let cellNode = MarkdownTableCellNode()
+                    cellNode.addChild(MarkdownTextNode(value: cell))
+                    headerNode.addChild(cellNode)
+                }
+                table.addChild(headerNode)
+
+                for row in rows {
+                    let rowNode = MarkdownTableRowNode()
+                    for cell in row {
+                        let cellNode = MarkdownTableCellNode()
+                        cellNode.addChild(MarkdownTextNode(value: cell))
+                        rowNode.addChild(cellNode)
+                    }
+                    table.addChild(rowNode)
+                }
+
+                context = ctx
+                context.currentNode.addChild(table)
+            } else {
+                context.index = startIndex
+                context.currentNode.addChild(MarkdownTableNode(value: header.joined(separator: "|")))
             }
         }
     }

Sources/SwiftParser/Languages/MarkdownNodes.swift

@@ -175,6 +175,24 @@ public final class MarkdownTableNode: CodeNode {
     }
 }
 
+public final class MarkdownTableHeaderNode: CodeNode {
+    public init(value: String = "", range: Range<String.Index>? = nil) {
+        super.init(type: MarkdownLanguage.Element.tableHeader, value: value, range: range)
+    }
+}
+
+public final class MarkdownTableRowNode: CodeNode {
+    public init(value: String = "", range: Range<String.Index>? = nil) {
+        super.init(type: MarkdownLanguage.Element.tableRow, value: value, range: range)
+    }
+}
+
+public final class MarkdownTableCellNode: CodeNode {
+    public init(value: String = "", range: Range<String.Index>? = nil) {
+        super.init(type: MarkdownLanguage.Element.tableCell, value: value, range: range)
+    }
+}
+
 public final class MarkdownAutoLinkNode: CodeNode {
     public let url: String
 

Tests/SwiftParserTests/SwiftParserTests.swift

@@ -356,11 +356,37 @@ final class SwiftParserTests: XCTestCase {
 
     func testMarkdownTable() {
         let parser = SwiftParser()
-        let source = "|a|b|\n"
+        let source = "|a|b|\n|---|---|\n|c|d|"
         let result = parser.parse(source, language: MarkdownLanguage())
         XCTAssertEqual(result.errors.count, 0)
-        XCTAssertEqual(result.root.children.first?.type as? MarkdownLanguage.Element, .table)
-        XCTAssertEqual(result.root.children.first?.value, "a|b")
+        let table = result.root.children.first as? MarkdownTableNode
+        XCTAssertNotNil(table)
+        XCTAssertEqual(table?.children.count, 2)
+        let header = table?.children.first as? MarkdownTableHeaderNode
+        XCTAssertEqual(header?.children.first?.children.first?.value, "a")
+        XCTAssertEqual(header?.children.last?.children.first?.value, "b")
+        let row = table?.children.last as? MarkdownTableRowNode
+        XCTAssertEqual(row?.children.first?.children.first?.value, "c")
+        XCTAssertEqual(row?.children.last?.children.first?.value, "d")
+    }
+
+    func testMarkdownTableVariants() {
+        let sources = [
+            "| Name  | Age |\n|-------|-----|\n| Alice |  25 |\n| Bob   |  30 |",
+            "| Name  | Age |\n|-------|:-----:|\n| Alice |  25 |\n| Bob   |  30 |",
+            "| Name  | Age |\n|-------|-----|\n| Alice |  25 |\n| Bob   |  30 "
+        ]
+        for src in sources {
+            let parser = SwiftParser()
+            let result = parser.parse(src, language: MarkdownLanguage())
+            XCTAssertEqual(result.errors.count, 0)
+            let table = result.root.children.first as? MarkdownTableNode
+            XCTAssertNotNil(table)
+            XCTAssertEqual(table?.children.count, 3)
+            let header = table?.children.first as? MarkdownTableHeaderNode
+            XCTAssertEqual(header?.children[0].children.first?.value, "Name")
+            XCTAssertEqual(header?.children[1].children.first?.value, "Age")
+        }
     }
 
     func testMarkdownLinkReferenceDefinition() {