From 8eaf6d6878a20495edd6052c0c4d064b56c60cf9 Mon Sep 17 00:00:00 2001
From: Khan Winter <35942988+thecoolwinter@users.noreply.github.com>
Date: Sat, 25 May 2024 10:55:48 -0500
Subject: [PATCH] Add Newline String Option

---
 .../NewlineProcessingFilter.swift             |  4 +-
 .../NewlineProcessingFilterTests.swift        | 37 +++++++++++++++++++
 2 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/Sources/TextFormation/NewlineProcessingFilter.swift b/Sources/TextFormation/NewlineProcessingFilter.swift
index 1626bee..1403e5a 100644
--- a/Sources/TextFormation/NewlineProcessingFilter.swift
+++ b/Sources/TextFormation/NewlineProcessingFilter.swift
@@ -4,8 +4,8 @@ import TextStory
 public class NewlineProcessingFilter {
     private let recognizer: ConsecutiveCharacterRecognizer
 
-    public init() {
-        self.recognizer = ConsecutiveCharacterRecognizer(matching: "\n")
+    public init(newline: String = "\n") {
+        self.recognizer = ConsecutiveCharacterRecognizer(matching: newline)
     }
 
     private func filterHandler(_ mutation: TextMutation, in interface: TextInterface, with providers: WhitespaceProviders) -> FilterAction {
diff --git a/Tests/TextFormationTests/NewlineProcessingFilterTests.swift b/Tests/TextFormationTests/NewlineProcessingFilterTests.swift
index 4b11eaf..8e9189c 100644
--- a/Tests/TextFormationTests/NewlineProcessingFilterTests.swift
+++ b/Tests/TextFormationTests/NewlineProcessingFilterTests.swift
@@ -68,4 +68,41 @@ final class NewlineProcessingFilterTests: XCTestCase {
 		XCTAssertEqual(interface.string, "\t\n\t\n\t")
 		XCTAssertEqual(interface.insertionLocation, 5)
 	}
+
+    func testMatchingWithUnknownNewline() {
+        let interface = TextInterfaceAdapter("")
+        let filter = NewlineProcessingFilter(newline: "crlf")
+
+        let mutation = TextMutation(insert: "crlf", at: 0, limit: 0)
+
+        XCTAssertEqual(filter.processMutation(mutation, in: interface, with: Self.providers), .discard)
+
+        XCTAssertEqual(interface.string, "crlf\t")
+        XCTAssertEqual(interface.insertionLocation, 5)
+    }
+
+    func testMatchingWithUnknownNewlineAndTrailingWhitespace() {
+        let interface = TextInterfaceAdapter(" ")
+        let filter = NewlineProcessingFilter(newline: "crlf")
+
+        let mutation = TextMutation(insert: "crlf", at: 1, limit: 1)
+
+        XCTAssertEqual(interface.insertionLocation, 1)
+        XCTAssertEqual(filter.processMutation(mutation, in: interface, with: Self.providers), .discard)
+
+        XCTAssertEqual(interface.string, " crlf\t")
+        XCTAssertEqual(interface.insertionLocation, 6)
+    }
+
+    func testMatchingWithUnknownNewlineAndTrailingTab() {
+        let interface = TextInterfaceAdapter("abc\t")
+        let filter = NewlineProcessingFilter(newline: "crlf")
+
+        let mutation = TextMutation(insert: "crlf", at: 4, limit: 4)
+
+        XCTAssertEqual(filter.processMutation(mutation, in: interface, with: Self.providers), .discard)
+
+        XCTAssertEqual(interface.string, "abc crlf\t")
+        XCTAssertEqual(interface.insertionLocation, 9)
+    }
 }