Form ASCII bitsets for quoted sequences in character classes

Author: hamishknight

Sources/_StringProcessing/ConsumerInterface.swift

@@ -327,24 +327,25 @@ extension DSLTree.CustomCharacterClass.Member {
     _ opts: MatchingOptions,
     _ isInverted: Bool
   ) -> DSLTree.CustomCharacterClass.AsciiBitset? {
+    typealias Bitset = DSLTree.CustomCharacterClass.AsciiBitset
     switch self {
     case let .atom(a):
       if let val = a.singleScalarASCIIValue {
-        return DSLTree.CustomCharacterClass.AsciiBitset(
-          val,
-          isInverted,
-          opts.isCaseInsensitive
-        )
+        return Bitset(val, isInverted, opts.isCaseInsensitive)
       }
     case let .range(low, high):
-      if let lowVal = low.singleScalarASCIIValue, let highVal = high.singleScalarASCIIValue {
-        return DSLTree.CustomCharacterClass.AsciiBitset(
-          low: lowVal,
-          high: highVal,
-          isInverted: isInverted,
-          isCaseInsensitive: opts.isCaseInsensitive
-        )
+      if let lowVal = low.singleScalarASCIIValue,
+         let highVal = high.singleScalarASCIIValue {
+        return Bitset(low: lowVal, high: highVal, isInverted: isInverted,
+                      isCaseInsensitive: opts.isCaseInsensitive)
+      }
+    case .quotedLiteral(let str):
+      var bitset = Bitset(isInverted: isInverted)
+      for c in str {
+        guard let ascii = c._singleScalarAsciiValue else { return nil }
+        bitset = bitset.union(Bitset(ascii, isInverted, opts.isCaseInsensitive))
       }
+      return bitset
     default:
       return nil
     }

Tests/RegexTests/CompileTests.swift

@@ -317,6 +317,15 @@ extension RegexTests {
       semanticLevel: .unicodeScalar,
       contains: [.matchBitsetScalar],
       doesNotContain: [.matchBitset, .consumeBy])
+    expectProgram(
+      for: #"[\Qab\Ec]"#,
+      contains: [.matchBitset],
+      doesNotContain: [.consumeBy, .matchBitsetScalar])
+    expectProgram(
+      for: #"[\Qab\Ec]"#,
+      semanticLevel: .unicodeScalar,
+      contains: [.matchBitsetScalar],
+      doesNotContain: [.matchBitset, .consumeBy])
   }
 
   func testScalarOptimizeCompilation() {