Add comma separated number special candidate

Sources/KanaKanjiConverterModule/Converter/CommaSeparatedNumber.swift

@@ -0,0 +1,46 @@
+import Foundation
+
+extension KanaKanjiConverter {
+    func commaSeparatedNumberCandidates(_ inputData: ComposingText) -> [Candidate] {
+        var text = inputData.convertTarget
+        guard !text.isEmpty else { return [] }
+
+        var negative = false
+        if text.first == "-" {
+            negative = true
+            text.removeFirst()
+        }
+        let parts = text.split(separator: ".", omittingEmptySubsequences: false)
+        guard parts.count <= 2,
+              parts.allSatisfy({ !$0.isEmpty && $0.allSatisfy({ $0.isNumber && $0.isASCII }) }) else {
+            return []
+        }
+        let integerPart = parts[0]
+        guard integerPart.count > 3 else { return [] }
+
+        var reversed = Array(integerPart.reversed())
+        var formatted = ""
+        for (i, ch) in reversed.enumerated() {
+            if i > 0 && i % 3 == 0 {
+                formatted.append(",")
+            }
+            formatted.append(ch)
+        }
+        let integerString = String(formatted.reversed())
+        var result = (negative ? "-" : "") + integerString
+        if parts.count == 2 {
+            let fractional = parts[1]
+            result += "." + fractional
+        }
+
+        let ruby = inputData.convertTarget.toKatakana()
+        let candidate = Candidate(
+            text: result,
+            value: -10,
+            correspondingCount: inputData.input.count,
+            lastMid: MIDData.一般.mid,
+            data: [DicdataElement(word: result, ruby: ruby, cid: CIDData.固有名詞.cid, mid: MIDData.一般.mid, value: -10)]
+        )
+        return [candidate]
+    }
+}

Sources/KanaKanjiConverterModule/Converter/ConvertRequestOptions.swift

@@ -83,6 +83,7 @@ public struct ConvertRequestOptions: Sendable {
         specialCandidateProviders.append(.timeExpression)
         specialCandidateProviders.append(.calendar)
         specialCandidateProviders.append(.version)
+        specialCandidateProviders.append(.commaSeparatedNumber)
 
         self.N_best = N_best
         self.requireJapanesePrediction = requireJapanesePrediction

Sources/KanaKanjiConverterModule/Converter/KanaKanjiConverter.swift

@@ -23,7 +23,8 @@ import EfficientNGram
         EmailAddressSpecialCandidateProvider(),
         UnicodeSpecialCandidateProvider(),
         VersionSpecialCandidateProvider(),
-        TimeExpressionSpecialCandidateProvider()
+        TimeExpressionSpecialCandidateProvider(),
+        CommaSeparatedNumberSpecialCandidateProvider()
     ]
     @MainActor private var checker = SpellChecker()
     private var checkerInitialized: [KeyboardLanguage: Bool] = [.none: true, .ja_JP: true]

Sources/KanaKanjiConverterModule/Converter/SpecialCandidateProvider.swift

@@ -45,6 +45,13 @@ public struct TimeExpressionSpecialCandidateProvider: SpecialCandidateProvider {
     }
 }
 
+public struct CommaSeparatedNumberSpecialCandidateProvider: SpecialCandidateProvider {
+    public init() {}
+    @MainActor public func provideCandidates(converter: KanaKanjiConverter, inputData: ComposingText, options _: ConvertRequestOptions) -> [Candidate] {
+        converter.commaSeparatedNumberCandidates(inputData)
+    }
+}
+
 public extension SpecialCandidateProvider where Self == CalendarSpecialCandidateProvider {
     static var calendar: Self { .init() }
 }
@@ -68,3 +75,7 @@ public extension SpecialCandidateProvider where Self == VersionSpecialCandidateP
 public extension SpecialCandidateProvider where Self == TimeExpressionSpecialCandidateProvider {
     static var timeExpression: Self { .init() }
 }
+
+public extension SpecialCandidateProvider where Self == CommaSeparatedNumberSpecialCandidateProvider {
+    static var commaSeparatedNumber: Self { .init() }
+}

Tests/KanaKanjiConverterModuleTests/ConverterTests/CommaSeparatedNumberTests.swift

@@ -0,0 +1,41 @@
+import XCTest
+@testable import KanaKanjiConverterModule
+
+final class CommaSeparatedNumberTests: XCTestCase {
+    private func makeDirectInput(direct input: String) -> ComposingText {
+        ComposingText(
+            convertTargetCursorPosition: input.count,
+            input: input.map { .init(character: $0, inputStyle: .direct) },
+            convertTarget: input
+        )
+    }
+
+    func testCommaSeparatedNumberCandidates() async throws {
+        let converter = await KanaKanjiConverter()
+
+        func result(_ text: String) async -> [Candidate] {
+            await converter.commaSeparatedNumberCandidates(makeDirectInput(direct: text))
+        }
+
+        let r1 = await result("49000")
+        XCTAssertEqual(r1.first?.text, "49,000")
+
+        let r2 = await result("109428081")
+        XCTAssertEqual(r2.first?.text, "109,428,081")
+
+        let r3 = await result("2129.49")
+        XCTAssertEqual(r3.first?.text, "2,129.49")
+
+        let r4 = await result("-13932")
+        XCTAssertEqual(r4.first?.text, "-13,932")
+
+        let r5 = await result("12")
+        XCTAssertTrue(r5.isEmpty)
+
+        let r6 = await result("1A9B")
+        XCTAssertTrue(r6.isEmpty)
+
+        let r7 = await result("１２３")
+        XCTAssertTrue(r7.isEmpty)
+    }
+}