Expose and fix re-triggering in ClosePairFilter

Author: mattmassicotte

Sources/TextFormation/ClosePairFilter.swift

@@ -28,6 +28,11 @@ public struct ClosePairFilter<Interface: TextSystemInterface> {
 		// behavior better.
 		self.processAfterTrigger = open != close
 	}
+
+	private mutating func resetState() {
+		recognizer.resetState()
+		self.triggerPosition = nil
+	}
 }
 
 extension ClosePairFilter: Filter {
@@ -63,7 +68,7 @@ extension ClosePairFilter: Filter {
 			interface.offset(from: mutation.range.lowerBound, to: pos) == 0,
 			interface.offset(from: mutation.range.upperBound, to: pos) == 0
 		else {
-			recognizer.resetState()
+			resetState()
 			return nil
 		}
 

Tests/TextFormationTests/ClosePairFilterTests.swift

@@ -208,6 +208,27 @@ struct ClosePairFilterTests {
 		#expect(system.string == "' ")
 	}
 
+	@Test func matchingThenDeleteAndInsert() throws {
+		let system = MockSystem(string: "")
+		var filter = ClosePairFilter<MockSystem>(open: "'", close: "'")
+
+		let openOutput = try #require(try system.runFilter(&filter, 0..<0, "'"))
+		#expect(openOutput == MutationOutput(selection: NSRange(1..<1), delta: 1))
+		#expect(system.string == "'")
+
+		let insert1 = try #require(try system.runFilter(&filter, 1..<1, "a"))
+		#expect(insert1 == MutationOutput(selection: NSRange(2..<2), delta: 2))
+		#expect(system.string == "'a'")
+
+		let delete = try #require(try system.runFilter(&filter, 1..<2, ""))
+		#expect(delete == MutationOutput(selection: NSRange(1..<1), delta: -1))
+		#expect(system.string == "''")
+
+		let insert2 = try #require(try system.runFilter(&filter, 1..<1, "a"))
+		#expect(insert2 == MutationOutput(selection: NSRange(2..<2), delta: 1))
+		#expect(system.string == "'a'")
+	}
+
 	@Test func matchingWithNewlineNoWhitespaceReturned() throws {
 		let system = MockSystem(string: "")
 		var filter = ClosePairFilter<MockSystem>(open: "abc", close: "def")