Solution: HTML table DSL
fun table(init: TableBuilder.() -> Unit): TableBuilder =
TableBuilder().apply(init)
data class TableBuilder(
var trs: List<TrBuilder> = emptyList()
) {
fun tr(init: TrBuilder.() -> Unit) {
trs += TrBuilder().apply(init)
}
override fun toString(): String =
"<table>${trs.joinToString(separator = "")}</table>"
}
data class TrBuilder(
var tds: List<TdBuilder> = emptyList()
) {
fun td(init: TdBuilder.() -> Unit) {
tds += TdBuilder().apply(init)
}
override fun toString(): String =
"<tr>${tds.joinToString(separator = "")}</tr>"
}
data class TdBuilder(var text: String = "") {
operator fun String.unaryPlus() {
text += this
}
override fun toString(): String = "<td>$text</td>"
}
Example solution in playground
import org.junit.Test
import kotlin.test.assertEquals
fun createTable(): TableBuilder = table {
tr {
td { +"A" }
td { +"B" }
}
tr {
td { +"C" }
td { +"D" }
}
}
fun table(init: TableBuilder.() -> Unit): TableBuilder =
TableBuilder().apply(init)
data class TableBuilder(
var trs: List<TrBuilder> = emptyList()
) {
fun tr(init: TrBuilder.() -> Unit) {
trs += TrBuilder().apply(init)
}
override fun toString(): String =
"<table>${trs.joinToString(separator = "")}</table>"
}
data class TrBuilder(
var tds: List<TdBuilder> = emptyList()
) {
fun td(init: TdBuilder.() -> Unit) {
tds += TdBuilder().apply(init)
}
override fun toString(): String =
"<tr>${tds.joinToString(separator = "")}</tr>"
}
data class TdBuilder(var text: String = "") {
operator fun String.unaryPlus() {
text += this
}
override fun toString(): String = "<td>$text</td>"
}
fun main() {
// println(createTable()) //<table><tr><td>This is row 1</td><td>This is row 2</td></tr></table>
}
class HtmlDslTest {
@Test
fun createTableTest() {
val html = TableBuilder().apply {
trs += TrBuilder().apply {
tds += TdBuilder().apply { text = "A" }
tds += TdBuilder().apply { text = "B" }
}
trs += TrBuilder().apply {
tds += TdBuilder().apply { text = "C" }
tds += TdBuilder().apply { text = "D" }
}
}
assertEquals(html, createTable())
}
@Test
fun `Table can be created and it is empty by default`() {
val expected = TableBuilder()
val actual = table {}
assertEquals(expected, actual)
}
@Test
fun `Tr can be created and it is empty`() {
val expected = TableBuilder().apply {
trs += TrBuilder()
}
val actual = table {
tr {}
}
assertEquals(expected, actual)
}
@Test
fun `Multiple tr can be created`() {
val expected = TableBuilder().apply {
trs += TrBuilder()
trs += TrBuilder()
}
val actual = table {
tr {}
tr {}
}
assertEquals(expected, actual)
}
@Test
fun `Td can be created and it is empty`() {
val expected = TableBuilder().apply {
trs += TrBuilder().apply {
tds += TdBuilder()
}
}
val actual = table {
tr {
td {}
}
}
assertEquals(expected, actual)
}
@Test
fun dslTestStandard() {
val expected = TableBuilder().apply {
trs += TrBuilder().apply {
tds += TdBuilder().apply { text = "A" }
tds += TdBuilder().apply { text = "B" }
}
trs += TrBuilder().apply {
tds += TdBuilder().apply { text = "C" }
tds += TdBuilder().apply { text = "D" }
}
}
val actual = table {
tr {
td { +"A" }
td { +"B" }
}
tr {
td { +"C" }
td { +"D" }
}
}
assertEquals(expected, actual)
}
@Test
fun dslTestMoreColons() {
val expected = TableBuilder().apply {
trs += TrBuilder().apply {
tds += TdBuilder().apply { text = "A" }
tds += TdBuilder().apply { text = "B" }
tds += TdBuilder().apply { text = "C" }
}
trs += TrBuilder().apply {
tds += TdBuilder().apply { text = "C" }
tds += TdBuilder().apply { text = "D" }
}
}
val actual = table {
tr {
td { +"A" }
td { +"B" }
td { +"C" }
}
tr {
td { +"C" }
td { +"D" }
}
}
assertEquals(expected, actual)
}
}
