New J2K: Main function conversion

j2k/newSrc/org/jetbrains/kotlin/j2k/ConversionsRunner.kt

@@ -44,6 +44,7 @@ object ConversionsRunner {
             +InsertDefaultPrimaryConstructorConversion(context)
             +FieldInitializersInPrimaryFromParamsConversion(context)
             +JavaMethodToKotlinFunctionConversion()
+            +MainFunctionConversion()
             +LiteralConversion()
             +InnerClassConversion()
             +ModifiersConversion(context)

j2k/newSrc/org/jetbrains/kotlin/j2k/conversions/MainFunctionConversion.kt

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2010-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.j2k.conversions
+
+import org.jetbrains.kotlin.j2k.ast.Nullability
+import org.jetbrains.kotlin.j2k.tree.*
+import org.jetbrains.kotlin.j2k.tree.impl.JKAnnotationImpl
+import org.jetbrains.kotlin.j2k.tree.impl.JKClassTypeImpl
+import org.jetbrains.kotlin.j2k.tree.impl.JKNameIdentifierImpl
+import org.jetbrains.kotlin.j2k.tree.impl.JKTypeElementImpl
+
+
+//TODO temporary
+class MainFunctionConversion : RecursiveApplicableConversionBase() {
+    override fun applyToElement(element: JKTreeElement): JKTreeElement {
+        if (element !is JKKtFunction) return recurse(element)
+        if (element.isMainFunctionDeclaration()) {
+            element.parameters.single().apply {
+                val oldType = type.type as JKClassType
+                val oldTypeParameter = oldType.parameters.single() as JKClassType
+                val newType =
+                    JKClassTypeImpl(
+                        oldType.classReference,
+                        listOf(oldTypeParameter.updateNullability(Nullability.NotNull)),
+                        Nullability.NotNull
+                    )
+                type = JKTypeElementImpl(newType)
+            }
+            element.annotationList.annotations += JKAnnotationImpl(JKNameIdentifierImpl("JvmStatic"))
+        }
+        return recurse(element)
+    }
+
+    fun JKKtFunction.isMainFunctionDeclaration(): Boolean {
+        val type = parameters.singleOrNull()?.type?.type as? JKClassType ?: return false
+        val typeArgument = type.parameters.singleOrNull() as? JKClassType ?: return false
+        return name.value == "main" &&
+                type.classReference.name == "Array" &&
+                typeArgument.classReference.name == "String"
+    }
+}