Add NorgLexerHEAD1.1.0main

1 files changed, 21 insertions, 0 deletions

diff --git a/Sources/NorgKit/Parsers/BlockScanner.swift b/Sources/NorgKit/Parsers/BlockScanner.swift
new file mode 100644
index 0000000..7552255
--- /dev/null
+++ b/Sources/NorgKit/Parsers/BlockScanner.swift
@@ -0,0 +1,21 @@
+/// Shared block-level lexical primitives.
+enum BlockScanner {
+
+  static let blockMarkers = ASCIIByteSet("*-~>")
+  static let rangeableMarkers = ASCIIByteSet("$^:")
+
+  enum Delimiter {
+    case weak, strong, rule
+  }
+
+  static func delimiter(_ s: Substring) -> Delimiter? {
+    guard s.count >= 2, let first = s.first, "-=_".contains(first),
+      s.allSatisfy({ $0 == first })
+    else { return nil }
+    switch first {
+    case "-": return .weak
+    case "=": return .strong
+    default: return .rule
+    }
+  }
+}