[K/JS]: KT-21626: Support const and let declarations in parser

Author: seclerp

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/jsexport/ExportModelToJsStatements.kt

@@ -60,6 +60,7 @@ class ExportModelToJsStatements(
                         val varName = JsName(declareNewNamespace(newNamespace), false)
                         val namespaceRef = jsElementAccess(element, currentRef)
                         statements += JsVars(
+                            JsVars.Variant.Var,
                             JsVars.JsVar(
                                 varName,
                                 JsAstUtils.or(
@@ -107,7 +108,7 @@ class ExportModelToJsStatements(
                             JsExport(property.name.makeRef(), JsName(declaration.name, false))
                         }
 
-                        listOf(JsVars(property), exportStatement)
+                        listOf(JsVars(JsVars.Variant.Var, property), exportStatement)
                     }
                     else -> {
                         val getter = declaration.irGetter?.let { staticContext.getNameForStaticDeclaration(it) }
@@ -234,7 +235,10 @@ class ExportModelToJsStatements(
         val bindConstructor = JsName("__bind_constructor_", false)
 
         val blockStatements = mutableListOf<JsStatement>(
-            JsVars(JsVars.JsVar(bindConstructor, innerClassRef.bindToThis(innerClassRef)))
+            JsVars(
+                JsVars.Variant.Var,
+                JsVars.JsVar(bindConstructor, innerClassRef.bindToThis(innerClassRef))
+            )
         )
 
         if (companionObject != null) {
@@ -280,7 +284,7 @@ class ExportModelToJsStatements(
             is JsNameRef -> classRef.name!! to null
             else -> {
                 val stableName = JsName(makeValidES5Identifier(name), true)
-                stableName to JsVars(JsVars.JsVar(stableName, classRef))
+                stableName to JsVars(JsVars.Variant.Var, JsVars.JsVar(stableName, classRef))
             }
         }
     }

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/IrDeclarationToJsTransformer.kt

@@ -51,7 +51,7 @@ class IrDeclarationToJsTransformer : BaseIrElementToJsNodeTransformer<JsStatemen
             initializerBlock.statements += jsAssignment(fieldName.makeRef(), initializer).makeStmt()
         }
 
-        return JsVars(JsVars.JsVar(fieldName))
+        return JsVars(JsVars.Variant.Var, JsVars.JsVar(fieldName))
     }
 
     override fun visitVariable(declaration: IrVariable, context: JsGenerationContext): JsStatement {

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/IrElementToJsStatementTransformer.kt

@@ -171,7 +171,7 @@ class IrElementToJsStatementTransformer : BaseIrElementToJsNodeTransformer<JsSta
             }
 
             SwitchOptimizer(context, isExpression = true, transformer).tryOptimize(value)?.let {
-                return JsBlock(JsVars(JsVars.JsVar(varName)), it).withSource(declaration, context)
+                return JsBlock(JsVars(JsVars.Variant.Var, JsVars.JsVar(varName)), it).withSource(declaration, context)
             }
         }
 
@@ -189,7 +189,7 @@ class IrElementToJsStatementTransformer : BaseIrElementToJsNodeTransformer<JsSta
             synthetic = syntheticVariable
             wasMovedFromItsDeclarationPlace = declaration.wasMovedFromItsDeclarationPlace
         }
-        return JsVars(variable).apply { synthetic = syntheticVariable }
+        return JsVars(JsVars.Variant.Var, variable).apply { synthetic = syntheticVariable }
     }
 
     override fun visitDelegatingConstructorCall(expression: IrDelegatingConstructorCall, context: JsGenerationContext): JsStatement {

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/JsClassGenerator.kt

@@ -93,7 +93,12 @@ class JsClassGenerator(private val irClass: IrClass, val context: JsGenerationCo
             }
         }
 
-        return JsCompositeBlock(interfaceDefaultsBlock.statements + listOf(JsVars(classHolder), functionWrapper.makeStmt())).also {
+        return JsCompositeBlock(
+            interfaceDefaultsBlock.statements + listOf(
+                JsVars(JsVars.Variant.Var, classHolder),
+                functionWrapper.makeStmt()
+            )
+        ).also {
             classModel.preDeclarationBlock.statements.clear()
             classModel.postDeclarationBlock.statements.clear()
         }

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/JsIrProgramFragment.kt

@@ -299,7 +299,7 @@ class CrossModuleReferences(
 
     private fun CrossModuleImport.generateImportVariableDeclaration(importedAs: JsName): JsStatement {
         val exportRef = JsNameRef(exportedAs, ReservedJsNames.makeCrossModuleNameRef(moduleExporter.internalName))
-        return JsVars(JsVars.JsVar(importedAs, exportRef))
+        return JsVars(JsVars.Variant.Var, JsVars.JsVar(importedAs, exportRef))
     }
 
     private fun CrossModuleImport.generateJsImportStatement(importedAs: JsName): JsStatement {
@@ -317,7 +317,7 @@ class CrossModuleReferences(
 fun JsStatement.renameImportedSymbolInternalName(newName: JsName): JsStatement {
     return when (this) {
         is JsImport -> JsImport(module, JsImport.Element((target as JsImport.Target.Elements).elements.single().name, newName.makeRef()))
-        is JsVars -> JsVars(JsVars.JsVar(newName, vars.single().initExpression))
+        is JsVars -> JsVars(JsVars.Variant.Var, JsVars.JsVar(newName, vars.single().initExpression))
         else -> error("Unexpected cross-module import statement ${this::class.qualifiedName}")
     }
 }

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/Merger.kt

@@ -335,7 +335,7 @@ class Merger(
         if (name == null) return this
 
         return when (this) {
-            is JsVars -> JsVars(JsVars.JsVar(name, vars.single().initExpression))
+            is JsVars -> JsVars(JsVars.Variant.Var, JsVars.JsVar(name, vars.single().initExpression))
             is JsImport -> JsImport(
                 module,
                 when (target) {

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/jsAstUtils.kt

@@ -81,7 +81,7 @@ fun jsElementAccess(name: String, receiver: JsExpression?): JsExpression =
     jsElementAccess(JsName(name, false), receiver)
 
 fun JsExpression.putIntoVariableWitName(name: JsName): JsVars {
-    return JsVars(JsVars.JsVar(name, this))
+    return JsVars(JsVars.Variant.Var, JsVars.JsVar(name, this))
 }
 
 fun jsElementAccess(name: JsName, computedName: JsExpression?, receiver: JsExpression?): JsExpression =
@@ -379,7 +379,7 @@ fun translateCall(
                 val iifeFun = JsFunction(
                     emptyScope,
                     JsBlock(
-                        JsVars(JsVars.JsVar(receiverName, jsDispatchReceiver)),
+                        JsVars(JsVars.Variant.Var, JsVars.JsVar(receiverName, jsDispatchReceiver)),
                         JsReturn(
                             JsInvocation(
                                 JsNameRef("apply", jsElementAccess(functionName.ident, receiverRef)),
@@ -598,7 +598,7 @@ object JsAstUtils {
     }
 
     fun newVar(name: JsName, expr: JsExpression?): JsVars {
-        return JsVars(JsVars.JsVar(name, expr))
+        return JsVars(JsVars.Variant.Var, JsVars.JsVar(name, expr))
     }
 }
 

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/utils/serialization/JsIrAstDeserializer.kt

@@ -290,6 +290,7 @@ private class JsIrAstDeserializer(private val source: ByteArray) {
     private val jsBinaryOperatorValues get() = JsBinaryOperator.entries
     private val jsUnaryOperatorValues get() = JsUnaryOperator.entries
     private val jsFunctionModifiersValues get() = JsFunction.Modifier.entries
+    private val jsVarVariants get() = JsVars.Variant.entries
 
     private fun readExpression(): JsExpression {
         return withComments {
@@ -458,7 +459,8 @@ private class JsIrAstDeserializer(private val source: ByteArray) {
     }
 
     private fun readVars(): JsVars {
-        return JsVars(readBoolean()).apply {
+        val variant = jsVarVariants[readInt()]
+        return JsVars(variant, readBoolean()).apply {
             readRepeated {
                 vars += withLocation {
                     JsVars.JsVar(nameTable[readInt()], ifTrue { readExpression() })

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/utils/serialization/JsIrAstSerializer.kt

@@ -604,6 +604,7 @@ private class JsIrAstSerializer {
     }
 
     private fun DataWriter.writeVars(vars: JsVars) {
+        writeInt(vars.variant.ordinal)
         writeBoolean(vars.isMultiline)
         writeCollection(vars.vars) { varDecl ->
             withLocation(varDecl) {

js/js.ast/src/org/jetbrains/kotlin/js/backend/JsToStringGenerationVisitor.java

@@ -54,6 +54,8 @@ public class JsToStringGenerationVisitor extends JsVisitor {
     private static final char[] CHARS_TRUE = "true".toCharArray();
     private static final char[] CHARS_TRY = "try".toCharArray();
     private static final char[] CHARS_VAR = "var".toCharArray();
+    private static final char[] CHARS_LET = "let".toCharArray();
+    private static final char[] CHARS_CONST = "const".toCharArray();
     private static final char[] CHARS_WHILE = "while".toCharArray();
     private static final char[] HEX_DIGITS = {
             '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
@@ -1301,7 +1303,12 @@ public void visitVars(@NotNull JsVars vars) {
         pushSourceInfo(vars.getSource());
         printCommentsBeforeNode(vars);
 
-        var();
+        switch (vars.getVariant()) {
+            case Var: var(); break;
+            case Let: let(); break;
+            case Const: _const(); break;
+        }
+
         space();
         boolean sep = false;
         for (JsVar var : vars) {
@@ -1833,6 +1840,14 @@ private void var() {
         p.print(CHARS_VAR);
     }
 
+    private void let() {
+        p.print(CHARS_LET);
+    }
+
+    private void _const() {
+        p.print(CHARS_CONST);
+    }
+
     private void _while() {
         p.print(CHARS_WHILE);
     }