initial implementation of function rest parameter support

mozilla/rhino#1451

common/src/main/java/dev/latvian/mods/rhino/CodeGenerator.java

@@ -170,6 +170,7 @@ private void generateICodeFromTree(Node tree) {
 		itsData.argNames = scriptOrFn.getParamAndVarNames();
 		itsData.argIsConst = scriptOrFn.getParamAndVarConst();
 		itsData.argCount = scriptOrFn.getParamCount();
+		itsData.argsHasRest = scriptOrFn.hasRestParameter();
 
 		itsData.encodedSourceStart = scriptOrFn.getEncodedSourceStart();
 		itsData.encodedSourceEnd = scriptOrFn.getEncodedSourceEnd();

common/src/main/java/dev/latvian/mods/rhino/IRFactory.java

@@ -61,6 +61,7 @@
 import dev.latvian.mods.rhino.ast.WhileLoop;
 import dev.latvian.mods.rhino.ast.WithStatement;
 import dev.latvian.mods.rhino.ast.Yield;
+import lombok.val;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -1933,13 +1934,21 @@ boolean isDestructuring(Node n) {
 	Node decompileFunctionHeader(FunctionNode fn) {
 		Node mexpr = null;
 		if (fn.getFunctionName() != null) {
+//			decompiler.addName(fn.getName());
 		} else if (fn.getMemberExprNode() != null) {
 			mexpr = transform(fn.getMemberExprNode());
 		}
-		boolean isArrow = fn.getFunctionType() == FunctionNode.ARROW_FUNCTION;
-		boolean noParen = isArrow && fn.getLp() == -1;
-		List<AstNode> params = fn.getParams();
-        for (AstNode param : params) {
+		val isArrow = fn.getFunctionType() == FunctionNode.ARROW_FUNCTION;
+		val noParen = isArrow && fn.getLp() == -1;
+		val params = fn.getParams();
+        for (int i = 0; i < params.size(); i++) {
+//			if (i > 0) {
+//				decompiler.addToken(Token.COMMA);
+//			}
+//			if (fn.hasRestParameter() && i == last) {
+//				decompiler.addToken(Token.DOTDOTDOT);
+//			}
+            val param = params.get(i);
             decompile(param);
         }
 		return mexpr;

common/src/main/java/dev/latvian/mods/rhino/InterpretedFunction.java

@@ -104,8 +104,8 @@ public Object resumeGenerator(Context cx, Scriptable scope, int operation, Objec
 
 	@Override
 	protected int getParamCount() {
-		return idata.argCount;
-	}
+        return idata.argsHasRest ? idata.argCount - 1 : idata.argCount;
+    }
 
 	@Override
 	protected int getParamAndVarCount() {

common/src/main/java/dev/latvian/mods/rhino/Interpreter.java

@@ -121,9 +121,9 @@ void initializeArgs(Context cx, Scriptable callerScope, Object[] args, double[]
 
 				if (useActivation) {
 					if (idata.itsFunctionType == FunctionNode.ARROW_FUNCTION) {
-						scope = ScriptRuntime.createArrowFunctionActivation(fnOrScript, scope, args, idata.isStrict);
+						scope = ScriptRuntime.createArrowFunctionActivation(fnOrScript, cx, scope, args, idata.isStrict, idata.argsHasRest);
 					} else {
-						scope = ScriptRuntime.createFunctionActivation(fnOrScript, scope, args, idata.isStrict);
+						scope = ScriptRuntime.createFunctionActivation(fnOrScript, cx, scope, args, idata.isStrict, idata.argsHasRest);
 					}
 				}
 			} else {

common/src/main/java/dev/latvian/mods/rhino/InterpreterData.java

@@ -15,6 +15,7 @@ final class InterpreterData implements Serializable {
 	static final int INITIAL_MAX_ICODE_LENGTH = 1024;
 	static final int INITIAL_STRINGTABLE_SIZE = 64;
 	static final int INITIAL_NUMBERTABLE_SIZE = 64;
+	boolean argsHasRest;
 
 	InterpreterData(String sourceFile, String encodedSource, boolean isStrict) {
 		this.itsSourceFile = sourceFile;

common/src/main/java/dev/latvian/mods/rhino/NativeCall.java

@@ -6,6 +6,8 @@
 
 package dev.latvian.mods.rhino;
 
+import lombok.val;
+
 /**
  * This class implements the activation object.
  * <p>
@@ -27,7 +29,15 @@ static void init(Scriptable scope, boolean sealed) {
 	NativeCall() {
 	}
 
-	NativeCall(NativeFunction function, Scriptable scope, Object[] args, boolean isArrow, boolean isStrict) {
+	NativeCall(
+		NativeFunction function,
+		Context cx,
+		Scriptable scope,
+		Object[] args,
+		boolean isArrow,
+		boolean isStrict,
+		boolean argsHasRest
+	) {
 		this.function = function;
 
 		setParentScope(scope);
@@ -40,10 +50,27 @@ static void init(Scriptable scope, boolean sealed) {
 		int paramAndVarCount = function.getParamAndVarCount();
 		int paramCount = function.getParamCount();
 		if (paramAndVarCount != 0) {
-			for (int i = 0; i < paramCount; ++i) {
-				String name = function.getParamOrVarName(i);
-				Object val = i < args.length ? args[i] : Undefined.instance;
-				defineProperty(name, val, PERMANENT);
+			if (argsHasRest) {
+				Object[] vals;
+				if (args.length >= paramCount) {
+					vals = new Object[args.length - paramCount];
+					System.arraycopy(args, paramCount, vals, 0, args.length - paramCount);
+				} else {
+					vals = ScriptRuntime.emptyArgs;
+				}
+
+				for (int i = 0; i < paramCount; ++i) {
+					val name = function.getParamOrVarName(i);
+					val val = i < args.length ? args[i] : Undefined.instance;
+					defineProperty(name, val, PERMANENT);
+				}
+				defineProperty(function.getParamOrVarName(paramCount), cx.newArray(scope, vals), PERMANENT);
+			} else {
+				for (int i = 0; i < paramCount; ++i) {
+					val name = function.getParamOrVarName(i);
+					val val = i < args.length ? args[i] : Undefined.instance;
+					defineProperty(name, val, PERMANENT);
+				}
 			}
 		}
 
@@ -56,7 +83,7 @@ static void init(Scriptable scope, boolean sealed) {
 
 		if (paramAndVarCount != 0) {
 			for (int i = paramCount; i < paramAndVarCount; ++i) {
-				String name = function.getParamOrVarName(i);
+				val name = function.getParamOrVarName(i);
 				if (!super.has(name, this)) {
 					if (function.getParamOrVarConst(i)) {
 						defineProperty(name, Undefined.instance, CONST);

common/src/main/java/dev/latvian/mods/rhino/Parser.java

@@ -8,6 +8,7 @@
 
 import dev.latvian.mods.rhino.ast.*;
 import dev.latvian.mods.rhino.ast.Symbol;
+import lombok.val;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -637,7 +638,12 @@ private void parseFunctionParams(FunctionNode fnNode) throws IOException {
 		do {
 			int tt = peekToken();
 			if (tt == Token.LB || tt == Token.LC) {
-				AstNode expr = destructuringPrimaryExpr();
+				if (fnNode.hasRestParameter()) {
+					// Error: parameter after rest parameter
+					reportError("msg.parm.after.rest", ts.tokenBeg, ts.tokenEnd - ts.tokenBeg);
+				}
+
+				val expr = destructuringPrimaryExpr();
 				markDestructuring(expr);
 				fnNode.addParam(expr);
 				// Destructuring assignment for parameters: add a dummy
@@ -646,18 +652,35 @@ private void parseFunctionParams(FunctionNode fnNode) throws IOException {
 				if (destructuring == null) {
 					destructuring = new HashMap<>();
 				}
-				String pname = currentScriptOrFn.getNextTempName();
+				val pname = currentScriptOrFn.getNextTempName();
 				defineSymbol(Token.LP, pname, false);
 				destructuring.put(pname, expr);
 			} else {
+				boolean wasRest = false;
+				if (tt == Token.DOTDOTDOT) {
+					if (fnNode.hasRestParameter()) {
+						// Error: parameter after rest parameter
+						reportError("msg.parm.after.rest", ts.tokenBeg, ts.tokenEnd - ts.tokenBeg);
+					}
+
+					fnNode.setHasRestParameter(true);
+					wasRest = true;
+					consumeToken();
+				}
+
 				if (mustMatchToken(Token.NAME, "msg.no.parm", true)) {
-					Name paramNameNode = createNameNode();
-					Comment jsdocNodeForName = getAndResetJsDoc();
+					if (!wasRest && fnNode.hasRestParameter()) {
+						// Error: parameter after rest parameter
+						reportError("msg.parm.after.rest", ts.tokenBeg, ts.tokenEnd - ts.tokenBeg);
+					}
+
+					val paramNameNode = createNameNode();
+					val jsdocNodeForName = getAndResetJsDoc();
 					if (jsdocNodeForName != null) {
 						paramNameNode.setJsDocNode(jsdocNodeForName);
 					}
 					fnNode.addParam(paramNameNode);
-					String paramName = ts.getString();
+					val paramName = ts.getString();
 					defineSymbol(Token.LP, paramName);
 					if (this.inUseStrictDirective) {
 						if ("eval".equals(paramName) || "arguments".equals(paramName)) {

common/src/main/java/dev/latvian/mods/rhino/ScriptRuntime.java

@@ -635,6 +635,33 @@ public static Object[] padArguments(Object[] args, int count) {
 		return result;
 	}
 
+	/**
+	 * Helper function for builtin objects that use the varargs form. ECMA function formal arguments
+	 * are undefined if not supplied; this function pads the argument array out to the expected
+	 * length, if necessary. Also, the rest parameter array construction is done here.
+	 */
+	public static Object[] padAndRestArguments(
+		Context cx, Scriptable scope, Object[] args, int argCount) {
+		Object[] result = new Object[argCount];
+		int paramCount = argCount - 1;
+		if (args.length < paramCount) {
+			System.arraycopy(args, 0, result, 0, args.length);
+			Arrays.fill(result, args.length, paramCount, Undefined.instance);
+		} else {
+			System.arraycopy(args, 0, result, 0, paramCount);
+		}
+
+		Object[] restValues;
+		if (args.length > paramCount) {
+			restValues = new Object[args.length - paramCount];
+			System.arraycopy(args, paramCount, restValues, 0, restValues.length);
+		} else {
+			restValues = ScriptRuntime.emptyArgs;
+		}
+		result[paramCount] = cx.newArray(scope, restValues);
+		return result;
+	}
+
 	public static String escapeString(String s) {
 		return escapeString(s, '"');
 	}
@@ -2915,12 +2942,36 @@ public static void initScript(NativeFunction funObj, Scriptable thisObj, Context
 		}
 	}
 
-	public static Scriptable createFunctionActivation(NativeFunction funObj, Scriptable scope, Object[] args, boolean isStrict) {
-		return new NativeCall(funObj, scope, args, false, isStrict);
+	public static Scriptable createFunctionActivation(
+		NativeFunction funObj,
+		Context cx,
+		Scriptable scope,
+		Object[] args,
+		boolean isStrict,
+		boolean argsHasRest
+	) {
+		return new NativeCall(funObj, cx, scope, args, false, isStrict, argsHasRest);
+	}
+
+	@Deprecated
+	public static Scriptable createFunctionActivation(NativeFunction funObj, Context cx, Scriptable scope, Object[] args, boolean isStrict) {
+		return createFunctionActivation(funObj, cx, scope, args, isStrict, false);
+	}
+
+	public static Scriptable createArrowFunctionActivation(
+		NativeFunction funObj,
+		Context cx,
+		Scriptable scope,
+		Object[] args,
+		boolean isStrict,
+		boolean argsHasRest
+	) {
+		return new NativeCall(funObj, cx, scope, args, true, isStrict, argsHasRest);
 	}
 
-	public static Scriptable createArrowFunctionActivation(NativeFunction funObj, Scriptable scope, Object[] args, boolean isStrict) {
-		return new NativeCall(funObj, scope, args, true, isStrict);
+	@Deprecated
+	public static Scriptable createArrowFunctionActivation(NativeFunction funObj, Context cx, Scriptable scope, Object[] args, boolean isStrict) {
+		return createArrowFunctionActivation(funObj, cx, scope, args, true, isStrict);
 	}
 
 	public static void enterActivationFunction(Context cx, Scriptable scope) {

common/src/main/java/dev/latvian/mods/rhino/Token.java

@@ -214,8 +214,9 @@ enum CommentType {
     int TEMPLATE_CHARS = TEMPLATE_LITERAL + 1;  // template literal - literal section
     int TEMPLATE_LITERAL_SUBST = TEMPLATE_CHARS + 1;  // template literal - substitution
     int TAGGED_TEMPLATE_LITERAL = TEMPLATE_LITERAL_SUBST + 1;  // template literal - tagged/handler
+    int DOTDOTDOT = 174; // spread/rest ...
 
-    int LAST_TOKEN = TAGGED_TEMPLATE_LITERAL;
+    int LAST_TOKEN = DOTDOTDOT;
 
 
     /**

common/src/main/java/dev/latvian/mods/rhino/TokenStream.java

@@ -1178,6 +1178,9 @@ final int getToken() throws IOException {
 				case ':':
 					return Token.COLON;
 				case '.':
+					if (matchChar('.') && matchChar('.')) {
+						return Token.DOTDOTDOT;
+					}
 					return Token.DOT;
 
 				case '|':

common/src/main/java/dev/latvian/mods/rhino/ast/FunctionNode.java

@@ -65,6 +65,7 @@ public class FunctionNode extends ScriptNode {
 	public static final int FUNCTION_EXPRESSION = 2;
 	public static final int FUNCTION_EXPRESSION_STATEMENT = 3;
 	public static final int ARROW_FUNCTION = 4;
+	private boolean hasRestParameter;
 
 	public enum Form {
 		FUNCTION, GETTER, SETTER, METHOD
@@ -397,6 +398,15 @@ public AstNode getMemberExprNode() {
 		return memberExprNode;
 	}
 
+	@Override
+	public boolean hasRestParameter() {
+		return hasRestParameter;
+	}
+
+	public void setHasRestParameter(boolean hasRestParameter) {
+		this.hasRestParameter = hasRestParameter;
+	}
+
 	/**
 	 * Visits this node, the function name node if supplied,
 	 * the parameters, and the body.  If there is a member-expr node,

common/src/main/java/dev/latvian/mods/rhino/ast/ScriptNode.java

@@ -335,6 +335,10 @@ public boolean isInStrictMode() {
 		return inStrictMode;
 	}
 
+	public boolean hasRestParameter() {
+		return false;
+	}
+
 	@Override
 	public void visit(NodeVisitor v) {
 		if (v.visit(this)) {