Add an utility to print generated code

Author: koperagen

core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/generateCode.kt

@@ -7,7 +7,7 @@ import org.jetbrains.kotlinx.dataframe.codeGen.MarkerVisibility
 public inline fun <reified T> DataFrame<T>.generateCode(
     fields: Boolean = true,
     extensionProperties: Boolean = true,
-): String {
+): CodeString {
     val name = markerName<T>()
     return generateCode(name, fields, extensionProperties)
 }
@@ -17,7 +17,7 @@ public fun <T> DataFrame<T>.generateCode(
     fields: Boolean = true,
     extensionProperties: Boolean = true,
     visibility: MarkerVisibility = MarkerVisibility.IMPLICIT_PUBLIC,
-): String {
+): CodeString {
     val codeGen = CodeGenerator.create()
     return codeGen.generate(
         schema = schema(),
@@ -26,10 +26,10 @@ public fun <T> DataFrame<T>.generateCode(
         extensionProperties = extensionProperties,
         isOpen = true,
         visibility = visibility,
-    ).code.declarations
+    ).code.declarations.toCodeString()
 }
 
-public inline fun <reified T> DataFrame<T>.generateInterfaces(): String = generateCode(
+public inline fun <reified T> DataFrame<T>.generateInterfaces(): CodeString = generateCode(
     fields = true,
     extensionProperties = false
 )
@@ -39,7 +39,7 @@ public inline fun <reified T> DataFrame<T>.generateDataClasses(
     extensionProperties: Boolean = true,
     visibility: MarkerVisibility = MarkerVisibility.IMPLICIT_PUBLIC,
     useFqNames: Boolean = false
-): String {
+): CodeString {
     val name = markerName ?: markerName<T>()
     val codeGen = CodeGenerator.create(useFqNames)
     return codeGen.generate(
@@ -51,15 +51,29 @@ public inline fun <reified T> DataFrame<T>.generateDataClasses(
         visibility = visibility,
         asDataClass = true
     ).code.declarations
+    ).code.declarations.toCodeString()
 }
 
 @PublishedApi
 internal inline fun <reified T> markerName(): String = if (T::class.isAbstract) {
     T::class.simpleName!!
 } else "DataEntry"
 
-public fun <T> DataFrame<T>.generateInterfaces(markerName: String): String = generateCode(
+public fun <T> DataFrame<T>.generateInterfaces(markerName: String): CodeString = generateCode(
     markerName = markerName,
     fields = true,
     extensionProperties = false
 )
+
+/**
+ * Converts delimited 'my_name', 'my name', etc, String to camelCase 'myName'
+ */
+public val NameNormalizer.Companion.default: NameNormalizer get() = NameNormalizer.from(setOf('\t', ' ', '_'))
+
+@JvmInline
+public value class CodeString(public val value: String) {
+    override fun toString(): String = value
+}
+
+@PublishedApi
+internal fun String.toCodeString(): CodeString = CodeString(this)

core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/print.kt

@@ -42,3 +42,5 @@ public fun <T, G> GroupBy<T, G>.print(): Unit = println(this)
 public fun DataFrameSchema.print(): Unit = println(this)
 
 // endregion
+
+public fun CodeString.print(): Unit = println(this)

core/src/test/kotlin/org/jetbrains/kotlinx/dataframe/api/gather.kt

@@ -117,7 +117,7 @@ class GatherTests {
 
     @Test
     fun `generated code is fully typed`() {
-        generatedCode.contains("<*>") shouldBe false
+        generatedCode.value.contains("<*>") shouldBe false
     }
 
     @Test

core/src/test/kotlin/org/jetbrains/kotlinx/dataframe/codeGen/CodeGenerationTests.kt

@@ -15,6 +15,7 @@ import org.jetbrains.kotlinx.dataframe.api.generateDataClasses
 import org.jetbrains.kotlinx.dataframe.api.groupBy
 import org.jetbrains.kotlinx.dataframe.api.move
 import org.jetbrains.kotlinx.dataframe.api.schema
+import org.jetbrains.kotlinx.dataframe.api.toCodeString
 import org.jetbrains.kotlinx.dataframe.api.toDataFrame
 import org.jetbrains.kotlinx.dataframe.api.under
 import org.jetbrains.kotlinx.dataframe.columns.ColumnGroup
@@ -326,7 +327,7 @@ class CodeGenerationTests : BaseTest() {
                 val group: List<Person1>,
                 val name: String
             )
-        """.trimIndent()
+        """.trimIndent().toCodeString()
     }
 
     @Test