Remove internal constants for box grid cell position

Author: cheonjaeung

grid/src/commonMain/kotlin/com/cheonjaeung/compose/grid/BoxGridCellPositionModifier.kt

@@ -7,8 +7,8 @@ import androidx.compose.ui.platform.InspectorInfo
 import androidx.compose.ui.unit.Density
 
 internal class BoxGridCellPositionElement(
-    val row: Int = BoxGridParentData.UNSPECIFIED_ROW,
-    val column: Int = BoxGridParentData.UNSPECIFIED_COLUMN,
+    val row: Int? = null,
+    val column: Int? = null,
     val inspectorInfo: InspectorInfo.() -> Unit
 ) : ModifierNodeElement<BoxGridCellPositionNode>() {
     override fun create(): BoxGridCellPositionNode {
@@ -39,15 +39,15 @@ internal class BoxGridCellPositionElement(
 }
 
 internal class BoxGridCellPositionNode(
-    var row: Int,
-    var column: Int
+    var row: Int?,
+    var column: Int?
 ) : Modifier.Node(), ParentDataModifierNode {
     override fun Density.modifyParentData(parentData: Any?): Any {
         val p = parentData as? BoxGridParentData ?: BoxGridParentData()
-        if (row != BoxGridParentData.UNSPECIFIED_ROW) {
+        if (row != null) {
             p.row = row
         }
-        if (column != BoxGridParentData.UNSPECIFIED_COLUMN) {
+        if (column != null) {
             p.column = column
         }
         return p

grid/src/commonMain/kotlin/com/cheonjaeung/compose/grid/BoxGridMeasurePolicy.kt

@@ -93,24 +93,10 @@ private class BoxGridMeasureHelper(
     }
 
     private val BoxGridParentData?.rowOrDefault: Int
-        get() {
-            val row = this?.row
-            return if (row == null || row == BoxGridParentData.UNSPECIFIED_ROW) {
-                BoxGridParentData.DEFAULT_ROW
-            } else {
-                row
-            }
-        }
+        get() = this?.row ?: 0
 
     private val BoxGridParentData?.columnOrDefault: Int
-        get() {
-            val column = this?.column
-            return if (column == null || column == BoxGridParentData.UNSPECIFIED_COLUMN) {
-                BoxGridParentData.DEFAULT_COLUMN
-            } else {
-                column
-            }
-        }
+        get() = this?.column ?: 0
 
     private val BoxGridParentData?.alignmentOrDefault: Alignment
         get() = this?.alignment ?: defaultAlignment

grid/src/commonMain/kotlin/com/cheonjaeung/compose/grid/BoxGridParentData.kt

@@ -3,15 +3,8 @@ package com.cheonjaeung.compose.grid
 import androidx.compose.ui.Alignment
 
 internal data class BoxGridParentData(
-    var row: Int = UNSPECIFIED_ROW,
-    var column: Int = UNSPECIFIED_COLUMN,
+    var row: Int? = null,
+    var column: Int? = null,
     var span: (BoxGridItemSpanScope.() -> BoxGridItemSpan)? = null,
     var alignment: Alignment? = null
-) {
-    companion object {
-        internal const val UNSPECIFIED_ROW: Int = -1
-        internal const val UNSPECIFIED_COLUMN: Int = -1
-        internal const val DEFAULT_ROW: Int = 0
-        internal const val DEFAULT_COLUMN: Int = 0
-    }
-}
+)