macos: fix backspace for latest syllable to continue composition

macOS/Patal/HangulLayout.swift

@@ -85,6 +85,9 @@ protocol HangulAutomata {
     func pickJungsung(by char: String) -> unichar?
     func pickJongsung(by char: String) -> unichar?
     func pickNonSyllable(by char: String) -> String?
+    func getChosungRawString(by chosung: 초성) -> String
+    func getJungsungRawString(by jungsung: 중성) -> String
+    func getJongsungRawString(by jongsung: 종성) -> String
 }
 
 /// 각 레이아웃이 가져야할 프로토콜의 공용 구현

macOS/Patal/HangulProcessor.swift

@@ -435,7 +435,6 @@ class HangulProcessor {
 
     /// 백스페이스가 들어오면 첫/가/끝의 역순으로 지움
     func applyBackspace() -> Int {
-        logger.debug("백스페이스 처리 전: \(String(describing: preedit)) \(previous)")
         if previous.last != nil {
             previous.removeLast()
         }
@@ -444,12 +443,17 @@ class HangulProcessor {
             print("아무것도 없음")
         case (.some(_), nil, nil):
             print("초성을 지워도 됨: \(String(describing: preedit))")
+            previous = []
             preedit.chosung = nil
-        case (_, .some(_), nil):
-            print("중성을 지워야 함: \(String(describing: preedit))")
+        case (let chosung, .some(_), nil):
+            print("중성을 지워야 함: \(String(describing: preedit)); 초성을 복구한다.")
+            let rawString = hangulLayout.getChosungRawString(by: chosung!)
+            previous = [rawString]
             preedit.jungsung = nil
-        case (_, _, .some(_)):
-            print("종성을 지움: \(String(describing: preedit))")
+        case (_, let jungsung, .some(_)):
+            print("종성을 지움: \(String(describing: preedit)); 중성을 복구한다.")
+            let rawString = hangulLayout.getJungsungRawString(by: jungsung!)
+            previous = [rawString]
             preedit.jongsung = nil
         }
         logger.debug("백스페이스 처리 후: \(String(describing: preedit)) \(previous)")

macOS/Patal/Layouts/Han3P3.swift

@@ -151,4 +151,32 @@ struct Han3P3Layout: HangulAutomata {
 
         return nonSyllable
     }
+
+    let chosungReverseIndex: [String] = [
+        "k", "kk", "h", "u", "y", "i", ";", ";;", "n", "nn",
+        "j", "l", "ll", "o", "'", "0", "p", "m",
+    ]
+
+    func getChosungRawString(by chosung: 초성) -> String {
+        return chosungReverseIndex[chosungMapOffset[chosung]!]
+    }
+
+    let jungsungReverseIndex: [String] = [
+        "f", "t", "6", "T", "r", "c", "e", "7", "v",
+        "/f", "/e", "/d", "4", "b", "9", "9r", "9c", "9d",
+        "5", "g", "8d", "d",
+    ]
+
+    func getJungsungRawString(by jungsung: 중성) -> String {
+        return jungsungReverseIndex[jungsungMapOffset[jungsung]!]
+    }
+
+    let jongsungReverseIndex: [String] = [
+        "x", "xx", "xq", "s", "sv", "sd", "S", "c", "w", "wx", "wz", "w3", "wq",
+        "we", "wf", "wd", "z", "3", "3q", "q", "2", "a", "v", "r", "1", "e", "f", "d",
+    ]
+
+    func getJongsungRawString(by jongsung: 종성) -> String {
+        return jongsungReverseIndex[jongsungMapOffset[jongsung]!]
+    }
 }

macOS/Patal/Layouts/Han3ShinP2.swift

@@ -161,4 +161,33 @@ struct Han3ShinP2Layout: HangulAutomata {
 
         return nonSyllable
     }
+
+    let chosungReverseIndex: [String] = [
+        "k", "kk", "h", "u", "uu", "y", "i", ";", ";;",
+        "n", "nn", "j", "l", "ll", "o", "'", "/", "p", "m",
+    ]
+
+    func getChosungRawString(by chosung: 초성) -> String {
+        return chosungReverseIndex[chosungMapOffset[chosung]!]
+    }
+
+    let jungsungReverseIndex: [String] = [
+        "f", "e", "w", "q", "r", "c", "t", "s", "v", "pf",
+        "pe", "pd", "x", "b", "o", "or", "oc", "od", "a",
+        "g", "g", "i", "id", "z", "d",
+    ]
+
+    func getJungsungRawString(by jungsung: 중성) -> String {
+        return jungsungReverseIndex[jungsungMapOffset[jungsung]!]
+    }
+
+    let jongsungReverseIndex: [String] = [
+        "c", "cc", "cq", "s", "sv", "sd", "g", "w", "wc", "wz",
+        "we", "wq", "wr", "wf", "wd", "z", "e", "eq", "q",
+        "x", "a", "v", "b", "t", "r", "f", "d",
+    ]
+
+    func getJongsungRawString(by jongsung: 종성) -> String {
+        return jongsungReverseIndex[jongsungMapOffset[jongsung]!]
+    }
 }

macOS/Patal/Layouts/Han3ShinPCS.swift

@@ -130,4 +130,33 @@ struct Han3ShinPcsLayout: HangulAutomata {
 
         return nonSyllable
     }
+
+    let chosungReverseIndex: [String] = [
+        "k", "kk", "h", "u", "uu", "y", "i", ";", ";;",
+        "n", "nn", "j", "l", "ll", "o", "'", "/", "p", "m",
+    ]
+
+    func getChosungRawString(by chosung: 초성) -> String {
+        return chosungReverseIndex[chosungMapOffset[chosung]!]
+    }
+
+    let jungsungReverseIndex: [String] = [
+        "f", "e", "w", "q", "r", "c", "t", "s", "v", "pf",
+        "pe", "pd", "x", "b", "o", "or", "oc", "od", "a",
+        "g", "g", "i", "id", "z", "d",
+    ]
+
+    func getJungsungRawString(by jungsung: 중성) -> String {
+        return jungsungReverseIndex[jungsungMapOffset[jungsung]!]
+    }
+
+    let jongsungReverseIndex: [String] = [
+        "c", "cc", "cq", "s", "sv", "sd", "g", "w", "wc", "wz",
+        "we", "wq", "wr", "wf", "wd", "z", "e", "eq", "q",
+        "x", "a", "v", "b", "t", "r", "f", "d",
+    ]
+
+    func getJongsungRawString(by jongsung: 종성) -> String {
+        return jongsungReverseIndex[jongsungMapOffset[jongsung]!]
+    }
 }

macOS/PatalTests/Processors/Hangul3ShinP2Tests.swift

@@ -880,6 +880,39 @@ struct Hangul3ShinP2Tests {
         #expect(c6 == "아")
     }
 
+    @Test("가←네")
+    func getComposedChar_가백스페이스네() {
+        var r1 = processor.verifyCombosable("k")
+        #expect(r1 == true)
+        processor.rawChar = "k"
+        let s1 = processor.한글조합()
+        #expect(s1 == CommitState.composing)
+        let c1 = processor.getComposed()
+        #expect(c1 == "ㄱ")
+
+        r1 = processor.verifyCombosable("f")
+        #expect(r1 == true)
+        processor.rawChar = "f"
+        let s2 = processor.한글조합()
+        #expect(s2 == CommitState.composing)
+        let c2 = processor.getComposed()
+        #expect(c2 == "가")
+
+        let countComposable = processor.applyBackspace()
+        #expect(countComposable == 1)
+
+        processor.rawChar = "h"
+        let s3 = processor.한글조합()
+        #expect(s3 == CommitState.committed)
+        let c3 = processor.getComposed()
+        #expect(c3 == "ㄴ")
+
+        processor.rawChar = "c"
+        let s4 = processor.한글조합()
+        #expect(s4 == CommitState.composing)
+        let c4 = processor.getComposed()
+        #expect(c4 == "네")
+    }
     //    @Test("강^H")
     //    func getComposedChar_강백스페이스() {
     //        let processor = HangulProcessor(layout: Layout.HAN3_SHIN_PCS)