feat: enhance RegexParser with group handling and capture functionality

lib/src/main/kotlin/org/example/Parser.kt

@@ -7,8 +7,11 @@ import com.github.h0tk3y.betterParse.lexer.literalToken
 import com.github.h0tk3y.betterParse.lexer.regexToken
 import com.github.h0tk3y.betterParse.lexer.token
 import com.github.h0tk3y.betterParse.parser.Parser
+import com.github.h0tk3y.betterParse.grammar.parseToEnd
 
 class RegexParser : Grammar<RegexItem>() {
+  private var groupCounter = 0
+
   // val bracketContent by regexToken("[^\\]]*")
   val escapedCharacter by regexToken("\\\\[+*?.()|\\[\\]]")
   val postfixOperator by regexToken("[+*?]")
@@ -49,7 +52,13 @@ class RegexParser : Grammar<RegexItem>() {
                   (dot asJust DotItem()) or
                   (escapedCharacter map { CharItem(it.text.substring(1)) }) or
                   (bracketContent map { BracketItem(it.text.substring(1, it.text.length - 1)) }) or
-                  (skip(openParenSymbol) and (parser(::rootParser)) and skip(closeParenSymbol))
+                  (skip(openParenSymbol) and
+                          (parser(::rootParser)) and
+                          skip(closeParenSymbol) map
+                          {
+                            val groupName = "${groupCounter++}"
+                            GroupItem(it, groupName)
+                          })
 
   val term: Parser<RegexItem> by
           (item and optional(postfixOperator)) map
@@ -76,3 +85,7 @@ class RegexParser : Grammar<RegexItem>() {
 
   override val rootParser: Parser<RegexItem> by termWithAlternation
 }
+
+fun compileRegex(input: String): RegexItem {
+  return RegexParser().parseToEnd(input)
+}

lib/src/main/kotlin/org/example/RegexItem.kt

@@ -3,6 +3,7 @@ package org.example
 data class State(
         val matched: String,
         val remaining: String,
+        val captures: Map<String, String> = emptyMap()
 )
 
 data class AvailableState(val seq: Sequence<State> = emptySequence()) : Sequence<State> by seq {
@@ -38,6 +39,11 @@ fun RegexItem.match(item: String): MatchResult {
   return MatchResult(this.findMatch(item))
 }
 
+fun RegexItem.test(item: String): Boolean {
+  // 매칭 결과가 성공인지 확인하는 헬퍼 함수
+  return this.match(item).isSuccess
+}
+
 class AndThenItem(val left: RegexItem, val right: RegexItem) : RegexItem {
   override fun toString(): String = "${left}${right}"
   override fun findMatch(str: String): AvailableState {
@@ -54,7 +60,11 @@ class AndThenItem(val left: RegexItem, val right: RegexItem) : RegexItem {
               if (!rightMatch.isEmpty) {
                 // If right match is successful, combine the matched parts
                 rightMatch.map { rightState ->
-                  State(state.matched + rightState.matched, rightState.remaining)
+                  State(
+                          state.matched + rightState.matched,
+                          rightState.remaining,
+                          state.captures + rightState.captures
+                  ) // Combine captures
                 }
               } else {
                 // If right match fails, return an empty sequence
@@ -107,6 +117,21 @@ class BracketItem(val content: String) : RegexItem {
   }
 }
 
+class GroupItem(val item: RegexItem, val name: String) : RegexItem {
+  override fun toString(): String = "(${item})"
+
+  override fun findMatch(str: String): AvailableState {
+    // 그룹은 내부 아이템과 동일하게 매칭을 시도
+    val ret = item.findMatch(str)
+    // 매칭된 상태에 그룹 이름을 추가하여 반환
+    return AvailableState(
+            ret.seq.map { state ->
+              State(state.matched, state.remaining, state.captures + (name to state.matched))
+            }
+    )
+  }
+}
+
 fun matchMany(
         str: String,
         item: RegexItem,
@@ -191,7 +216,7 @@ class DotItem : RegexItem {
 }
 
 class AlternationItem(val left: RegexItem, val right: RegexItem) : RegexItem {
-  override fun toString(): String = "(${left}|${right})"
+  override fun toString(): String = "${left}|${right}"
   override fun findMatch(str: String): AvailableState {
     // Alternation은 왼쪽 또는 오른쪽 항목 중 하나와 매칭되므로, 각각 시도해보고 성공하는 경우를 반환
     val leftMatch = left.findMatch(str)

lib/src/test/kotlin/org/example/ParserTest.kt

@@ -2,21 +2,19 @@ package org.example
 
 import kotlin.test.Test
 import kotlin.test.assertEquals
-import com.github.h0tk3y.betterParse.grammar.parseToEnd
 
 class ParserTest {
 
     @Test
     fun testSimpleCharacter() {
         val input = "a"
-        val result = RegexParser().parseToEnd(input)
+        val result = compileRegex(input)
-        assertEquals("a",result.toString())
+        assertEquals("a", result.toString())
     }
     @Test
     fun testCharacterWithPlus() {
         val input = "a+"
-        val parser = RegexParser()
+        val result = compileRegex(input)
-        val result = parser.parseToEnd(input)
         assertEquals("a+", result.toString())
         assert(result.match("a").isSuccess)
         assert(result.match("aa").isSuccess)
@@ -25,8 +23,7 @@ class ParserTest {
     @Test
     fun testCharacterWithStar() {
         val input = "b*"
-        val parser = RegexParser()
+        val result = compileRegex(input)
-        val result = parser.parseToEnd(input)
         assertEquals("b*", result.toString())
         assert(result.match("").isSuccess)
         assert(result.match("b").isSuccess)
@@ -36,8 +33,7 @@ class ParserTest {
     @Test
     fun testCharacterWithQuestion() {
         val input = "c?"
-        val parser = RegexParser()
+        val result = compileRegex(input)
-        val result = parser.parseToEnd(input)
         assertEquals("c?", result.toString())
         assert(result.match("").isSuccess)
         assert(result.match("c").isSuccess)
@@ -46,8 +42,7 @@ class ParserTest {
     @Test
     fun testDot() {
         val input = "."
-        val parser = RegexParser()
+        val result = compileRegex(input)
-        val result = parser.parseToEnd(input)
         assertEquals(".", result.toString())
         assert(result.match("a").isSuccess)
         assert(result.match("1").isSuccess)
@@ -57,9 +52,8 @@ class ParserTest {
     @Test
     fun testAlternation() {
         val input = "a|b"
-        val parser = RegexParser()
+        val result = compileRegex(input)
-        val result = parser.parseToEnd(input)
+        assertEquals("a|b", result.toString())
-        assertEquals("(a|b)", result.toString())
         assert(result.match("a").isSuccess)
         assert(result.match("b").isSuccess)
         assert(!result.match("c").isSuccess)
@@ -67,9 +61,8 @@ class ParserTest {
     @Test
     fun testParentheses() {
         val input = "(d)"
-        val parser = RegexParser()
+        val result = compileRegex(input)
-        val result = parser.parseToEnd(input)
+        assertEquals("(d)", result.toString())
-        assertEquals("d", result.toString())
         assert(result.match("d").isSuccess)
         assert(!result.match("e").isSuccess)
     }
@@ -77,8 +70,7 @@ class ParserTest {
     @Test
     fun testComplexExpression() {
         val input = "a(b|c)*d+"
-        val parser = RegexParser()
+        val result = compileRegex(input)
-        val result = parser.parseToEnd(input)
         assertEquals("a(b|c)*d+", result.toString())
         assert(result.match("ad").isSuccess)
         assert(!result.match("ab").isSuccess)
@@ -90,8 +82,7 @@ class ParserTest {
     @Test
     fun testAndThen() {
         val input = "ab"
-        val parser = RegexParser()
+        val result = compileRegex(input)
-        val result = parser.parseToEnd(input)
         assertEquals("ab", result.toString())
         assert(result.match("ab").isSuccess)
         assert(!result.match("a").isSuccess)
@@ -99,9 +90,8 @@ class ParserTest {
     }
     @Test
     fun testDotAndPlus() {
-        val input = ".+a";
+        val input = ".+a"
-        val parser = RegexParser()
+        val result = compileRegex(input)
-        val result = parser.parseToEnd(input)
         assertEquals(".+a", result.toString())
         assert(!result.match("a").isSuccess)
         assert(result.match("ba").isSuccess)
@@ -110,8 +100,7 @@ class ParserTest {
     @Test
     fun testEscapedCharacter() {
         val input = "\\+"
-        val parser = RegexParser()
+        val result = compileRegex(input)
-        val result = parser.parseToEnd(input)
         assertEquals("\\+", result.toString())
         assert(result.match("+").isSuccess)
         assert(!result.match("a").isSuccess)
@@ -119,12 +108,32 @@ class ParserTest {
     @Test
     fun testBracketContent() {
         val input = "[abc]"
-        val parser = RegexParser()
+        val result = compileRegex(input)
-        val result = parser.parseToEnd(input)
         assertEquals("[abc]", result.toString())
         assert(result.match("a").isSuccess)
         assert(result.match("b").isSuccess)
         assert(result.match("c").isSuccess)
         assert(!result.match("d").isSuccess)
     }
+    @Test
+    fun testNestedGroups() {
+        val input = "(a(b|c)d)+"
+        val result = compileRegex(input)
+        assertEquals("(a(b|c)d)+", result.toString())
+        assert(!result.match("ad").isSuccess)
+        assert(result.match("abd").isSuccess)
+        assert(result.match("acd").isSuccess)
+        assert(!result.match("a").isSuccess)
+    }
+    @Test
+    fun testCaptureGroups() {
+        val input = "(a)(b)"
+        val result = compileRegex(input)
+        assertEquals("(a)(b)", result.toString())
+        val matchResult = result.match("ab")
+        assert(matchResult.isSuccess)
+        val captures = matchResult.available.first();
+        assertEquals("a", captures.captures.get("0"))
+        assertEquals("b", captures.captures.get("1"))
+    }
 }