Easy and safe Minecraft/Forge NBT dsl example

ExampleItem.kt

class ExampleItem : Item(Properties().group(ItemGroup.MISC)) {
    /**
     * root
     * |- someString (String)
     * |- someBoolean (Boolean)
     * |- nested (Compound)
     * - |- immutableString (String)
     *   |- nullableUUID (UUID)
     *   |- evenMoreNested (Compound)
     *   - |- someIntArray (int[])
     *     |- someOtherIntArray (int[])
     *     -
     */
    inner class ExampleItemNBT(stack: ItemStack) : ItemNBTHolder(stack, stack.orCreateTag) {
        var someString by string("default")
        var someBoolean by boolean(false)
        val nested by compound(::NestedNBT)

        inner class NestedNBT(stack: ItemStack, compound: CompoundNBT) : ItemNBTHolder(stack, compound) {
            val immutableString by string("I am read-only")
            var nullableUUID by uuid()

            val evenMoreNested by compound(::MoreNestedNBT)

            inner class MoreNestedNBT(stack: ItemStack, compound: CompoundNBT) : ItemNBTHolder(stack, compound) {
                var someIntArray by intArray()
                var someOtherIntArray by intArray(arrayOf(1, 2, 3).toIntArray())
            }
        }
    }

    fun updateNBT() {
        ExampleItemNBT(toItemStack()).apply {
            someString = "Hallo"
            someBoolean = true

            nested {
                evenMoreNested {
                    someIntArray = arrayOf(6, 9, 4, 2, 0).toIntArray()
                }
            }
        }
    }

    fun checkNBT(): Boolean {
        return GlassShardNBT(toItemStack()).run {
            someString == "Hallo" && someBoolean && nested { nullableUUID != null }
        }
    }
}