fix: expose found removable comments in a block (#23)

This helps the caller decide whether to call rewritten function.

core/src/main/kotlin/cash/grammar/kotlindsl/utils/CommentsInBlockRemover.kt

@@ -1,5 +1,6 @@
 package cash.grammar.kotlindsl.utils
 
+import cash.grammar.kotlindsl.model.Assignment
 import cash.grammar.kotlindsl.parse.KotlinParseException
 import cash.grammar.kotlindsl.parse.Parser
 import cash.grammar.kotlindsl.parse.Rewriter
@@ -46,6 +47,14 @@ public class CommentsInBlockRemover private constructor(
   private val rewriter = Rewriter(tokens)
   private val indent = Whitespace.computeIndent(tokens, input)
   private val comments = Comments(tokens, indent)
+  private val foundRemovableComments = mutableListOf<String>()
+
+  /**
+   * Retrieves the list of comments found in the block and can be removed from the script.
+   *
+   * @return A list of comments that are eligible for removal.
+   */
+  public fun getFoundRemovableComments(): List<String> = foundRemovableComments
 
   @Throws(KotlinParseException::class)
   public fun rewritten(): String {
@@ -66,7 +75,11 @@ public class CommentsInBlockRemover private constructor(
         allInlineComments += inlineComments
       }
 
-      val nonInlineComments = comments.getCommentsInBlock(ctx).subtract(allInlineComments)
+      val allComments = comments.getCommentsInBlock(ctx)
+      foundRemovableComments.addAll(allComments.map { it.text })
+
+      // Delete non-inline comments
+      val nonInlineComments = allComments.subtract(allInlineComments)
       nonInlineComments.forEach { token ->
         rewriter.deleteWhitespaceToLeft(token)
         rewriter.deleteNewlineToRight(token)

core/src/test/kotlin/cash/grammar/kotlindsl/utils/CommentsInBlockRemoverTest.kt

@@ -26,7 +26,8 @@ class CommentsInBlockRemoverTest {
     """.trimMargin()
 
     // When
-    val rewrittenBuildScript = CommentsInBlockRemover.of(buildScript, "dependencies").rewritten()
+    val commentsInBlockRemover = CommentsInBlockRemover.of(buildScript, "dependencies")
+    val rewrittenBuildScript = commentsInBlockRemover.rewritten()
 
     // Then
     assertThat(rewrittenBuildScript).isEqualTo("""
@@ -42,5 +43,11 @@ class CommentsInBlockRemoverTest {
       |  // More comments 
       |}
     """.trimMargin())
+    assertThat(commentsInBlockRemover.getFoundRemovableComments()).containsOnly(
+      "/* This is a block comment\n  that spans multiple lines */",
+      "// This is an line comment",
+      "// This is a single-line comment",
+      "// This is another single-line comment",
+    )
   }
 }