org.mozilla.javascript.ast.FunctionNode Java Examples

private void generateNestedFunctions()
{
    int functionCount = scriptOrFn.getFunctionCount();
    if (functionCount == 0) return;

    InterpreterData[] array = new InterpreterData[functionCount];
    for (int i = 0; i != functionCount; i++) {
        FunctionNode fn = scriptOrFn.getFunctionNode(i);
        CodeGenerator gen = new CodeGenerator();
        gen.compilerEnv = compilerEnv;
        gen.scriptOrFn = fn;
        gen.itsData = new InterpreterData(itsData);
        gen.generateFunctionICode();
        array[i] = gen.itsData;
    }
    itsData.itsNestedFunctions = array;
}
 

@Override
public boolean visit(AstNode node) {
	if (node instanceof PropertyGet){
		PropertyGet pg = (PropertyGet)node;
		AstNode target = pg.getTarget();
		String propName = pg.getProperty().getIdentifier();
		if (target instanceof KeywordLiteral && ConstraintGenUtil.isThis(target)){
			if (node.getParent() instanceof Assignment){
				Assignment a = (Assignment)node.getParent();
				if (a.getLeft() == node){
					writtenProperties.add(propName);
				} else {
					readProperties.add(propName);
				}
			} else {
				readProperties.add(propName);
			}
			readProperties.removeAll(writtenProperties); // if something is read and written, it should only be in the written set
		}
	} else if (node instanceof FunctionNode) {
	    // don't recurse into nested function body
	    return false;
	}
	return true;
}
 

/**
 * For a function definition (FunctionNode), create constraints equating its
 * parameters to param(.) variables, and equate the type of the function name
 * to the type of the entire function definition.
 */
private void createFunctionNodeConstraints(FunctionNode node, ITypeTerm funTerm){
	// if the function has a name, equate the types of the function node and the function name
	Name funName = node.getFunctionName();
	if (funName != null){
		ITypeTerm nameTerm = findOrCreateNameDeclarationTerm(funName);
		addSubTypeConstraint(funTerm, nameTerm, node.getLineno(), null);
	}

	// for a function f with params v1, v2, ... generate param(|f|,i) = |v_i|
	for (int i=0; i < node.getParamCount(); i++){
		AstNode param = node.getParams().get(i);
		if (param instanceof Name){
			Name name = (Name)param;
			ITypeTerm nameVar = findOrCreateNameDeclarationTerm(name);
			ITypeTerm paramVar = findOrCreateFunctionParamTerm(funTerm, i, node.getParamCount(), node.getLineno());
			addTypeEqualityConstraint(paramVar, nameVar, param.getLineno(), null);
		} else {
			error("createFunctionNodeConstraints: unexpected parameter type", node);
		}
	}

}
 

/**
 * generate constraints for return statements
 */
private void processReturnStatement(ReturnStatement rs) throws Error {
	FunctionNode fun = ConstraintGenUtil.findEnclosingFunction(rs);
	FunctionTerm.FunctionKind funType =
			ConstraintGenUtil.isConstructor(fun) ? FunctionTerm.FunctionKind.Constructor :
			(ConstraintGenUtil.isMethod(fun) ? FunctionTerm.FunctionKind.Method : FunctionTerm.FunctionKind.Function);

	ITypeTerm funTerm = findOrCreateFunctionTerm(fun, funType);
	ITypeTerm returnTerm = findOrCreateFunctionReturnTerm(funTerm, fun.getParamCount(), rs.getLineno(), null);
	AstNode exp = rs.getReturnValue();
	if (exp != null){
		ITypeTerm expTerm = processExpression(exp);
		addSubTypeConstraint(expTerm, returnTerm, rs.getLineno(),
				(solution) -> subtypeError("bad return value " + shortSrc(exp),
						solution.typeOfTerm(expTerm), solution.typeOfTerm(returnTerm), locationOf(rs)));
	} else {
		ITypeTerm voidTerm = findOrCreateTypeTerm(new VoidType(), rs.getLineno());
		addTypeEqualityConstraint(voidTerm, returnTerm, rs.getLineno(),
				(solution) -> genericTypeError("missing return value", locationOf(rs))
						.withNote("expected " + describeTypeOf(returnTerm, solution)));
	}
}
 

/**
 * Find or create a term representing a FunctionNode (function definition). The
 * created FunctionTerm provides methods for accessing the terms corresponding to the
 * function's parameters and return type. The boolean flag isMethod indicates whether
 * the function is a method.
 */
public FunctionTerm findOrCreateFunctionTerm(FunctionNode fun, FunctionTerm.FunctionKind funType) {
    if (!functionTerms.containsKey(fun)){
        FunctionTerm var = new FunctionTerm(fun, funType);
        var.setReturnVariable(this.findOrCreateFunctionReturnTerm(var, fun.getParamCount()));
        List<AstNode> params = fun.getParams();
        List<NameDeclarationTerm> paramVars = new ArrayList<NameDeclarationTerm>();
        for (int i=0; i < params.size(); i++){
            AstNode param = params.get(i);
            if (param instanceof Name){
                NameDeclarationTerm paramCV = this.findOrCreateNameDeclarationTerm((Name)param);
                paramVars.add(paramCV);
            } else {
                throw new Error("unimplemented case in findOrCreateFunctionVariable");
            }
        }
        var.setParamVariables(paramVars);
        functionTerms.put(fun, var);
    }
    return functionTerms.get(fun);
}
 

/**
 * Checks every variable {@code v} in {@code source} is marked as a
 * number-variable iff {@code numbers} contains {@code v}
 */
protected void assertNumberVars(CharSequence source, String... numbers) {
    // wrap source in function
    ScriptNode tree = compile("function f(o, fn){" + source + "}");

    FunctionNode fnode = tree.getFunctionNode(0);
    assertNotNull(fnode);
    OptFunctionNode opt = OptFunctionNode.get(fnode);
    assertNotNull(opt);
    assertSame(fnode, opt.fnode);

    for (int i = 0, c = fnode.getParamCount(); i < c; ++i) {
        assertTrue(opt.isParameter(i));
        assertFalse(opt.isNumberVar(i));
    }

    Set<String> set = new HashSet<String>(asList(numbers));
    for (int i = fnode.getParamCount(), c = fnode.getParamAndVarCount(); i < c; ++i) {
        assertFalse(opt.isParameter(i));
        String name = fnode.getParamOrVarName(i);
        String msg = format("{%s -> number? = %b}", name, opt.isNumberVar(i));
        assertEquals(msg, set.contains(name), opt.isNumberVar(i));
    }
}
 

/**
 * Checks every variable {@code v} in {@code source} is marked as a
 * number-variable iff {@code numbers} contains {@code v}
 */
protected void assertNumberVars(CharSequence source, String... numbers) {
    // wrap source in function
    ScriptNode tree = compile("function f(){" + source + "}");

    FunctionNode fnode = tree.getFunctionNode(0);
    assertNotNull(fnode);
    OptFunctionNode opt = OptFunctionNode.get(fnode);
    assertNotNull(opt);
    assertSame(fnode, opt.fnode);

    for (int i = 0, c = fnode.getParamCount(); i < c; ++i) {
        assertTrue(opt.isParameter(i));
        assertFalse(opt.isNumberVar(i));
    }

    Set<String> set = new HashSet<String>(asList(numbers));
    for (int i = fnode.getParamCount(), c = fnode.getParamAndVarCount(); i < c; ++i) {
        assertFalse(opt.isParameter(i));
        String name = fnode.getParamOrVarName(i);
        String msg = format("{%s -> number? = %b}", name, opt.isNumberVar(i));
        assertEquals(msg, set.contains(name), opt.isNumberVar(i));
    }
}
 

private void generateNestedFunctions()
{
    int functionCount = scriptOrFn.getFunctionCount();
    if (functionCount == 0) return;

    InterpreterData[] array = new InterpreterData[functionCount];
    for (int i = 0; i != functionCount; i++) {
        FunctionNode fn = scriptOrFn.getFunctionNode(i);
        CodeGenerator gen = new CodeGenerator();
        gen.compilerEnv = compilerEnv;
        gen.scriptOrFn = fn;
        gen.itsData = new InterpreterData(itsData);
        gen.generateFunctionICode();
        array[i] = gen.itsData;
    }
    itsData.itsNestedFunctions = array;
}
 

private void generateFunctionICode()
{
    itsInFunctionFlag = true;

    FunctionNode theFunction = (FunctionNode)scriptOrFn;

    itsData.itsFunctionType = theFunction.getFunctionType();
    itsData.itsNeedsActivation = theFunction.requiresActivation();
    if (theFunction.getFunctionName() != null) {
        itsData.itsName = theFunction.getName();
    }
    if (theFunction.isGenerator()) {
      addIcode(Icode_GENERATOR);
      addUint16(theFunction.getBaseLineno() & 0xFFFF);
    }
    if (theFunction.isInStrictMode()) {
        itsData.isStrict = true;
    }

    generateICodeFromTree(theFunction.getLastChild());
}
 

private void transformCompilationUnit(ScriptNode tree, boolean inStrictMode)
{
    loops = new ObjArray();
    loopEnds = new ObjArray();

    // to save against upchecks if no finally blocks are used.
    hasFinally = false;

    // Flatten all only if we are not using scope objects for block scope
    boolean createScopeObjects = tree.getType() != Token.FUNCTION ||
                              ((FunctionNode)tree).requiresActivation();
    tree.flattenSymbolTable(!createScopeObjects);

    //uncomment to print tree before transformation
    if (Token.printTrees) System.out.println(tree.toStringTree(tree));
    transformCompilationUnit_r(tree, tree, tree, createScopeObjects,
                               inStrictMode);
}
 

PerFunctionVariables(FunctionNode fnNode) {
    savedCurrentScriptOrFn = Parser.this.currentScriptOrFn;
    Parser.this.currentScriptOrFn = fnNode;

    savedCurrentScope = Parser.this.currentScope;
    Parser.this.currentScope = fnNode;

    savedLabelSet = Parser.this.labelSet;
    Parser.this.labelSet = null;

    savedLoopSet = Parser.this.loopSet;
    Parser.this.loopSet = null;

    savedLoopAndSwitchSet = Parser.this.loopAndSwitchSet;
    Parser.this.loopAndSwitchSet = null;

    savedEndFlags = Parser.this.endFlags;
    Parser.this.endFlags = 0;

    savedInForInit = Parser.this.inForInit;
    Parser.this.inForInit = false;
}
 

private void generateFunctionICode()
{
    itsInFunctionFlag = true;

    FunctionNode theFunction = (FunctionNode)scriptOrFn;

    itsData.itsFunctionType = theFunction.getFunctionType();
    itsData.itsNeedsActivation = theFunction.requiresActivation();
    if (theFunction.getFunctionName() != null) {
        itsData.itsName = theFunction.getName();
    }
    if (theFunction.isGenerator()) {
      addIcode(Icode_GENERATOR);
      addUint16(theFunction.getBaseLineno() & 0xFFFF);
    }

    generateICodeFromTree(theFunction.getLastChild());
}
 

private void transformCompilationUnit(ScriptNode tree)
{
    loops = new ObjArray();
    loopEnds = new ObjArray();

    // to save against upchecks if no finally blocks are used.
    hasFinally = false;

    // Flatten all only if we are not using scope objects for block scope
    boolean createScopeObjects = tree.getType() != Token.FUNCTION ||
                              ((FunctionNode)tree).requiresActivation();
    tree.flattenSymbolTable(!createScopeObjects);

    //uncomment to print tree before transformation
    if (Token.printTrees) System.out.println(tree.toStringTree(tree));
    boolean inStrictMode = tree instanceof AstRoot &&
                           ((AstRoot)tree).isInStrictMode();
    transformCompilationUnit_r(tree, tree, tree, createScopeObjects,
                               inStrictMode);
}
 

protected void checkActivationName(String name, int token) {
    if (!insideFunction()) {
        return;
    }
    boolean activation = false;
    if ("arguments".equals(name) &&
        // An arrow function not generate arguments. So it not need activation.
        ((FunctionNode)currentScriptOrFn).getFunctionType() != FunctionNode.ARROW_FUNCTION) {
        activation = true;
    } else if (compilerEnv.getActivationNames() != null
            && compilerEnv.getActivationNames().contains(name)) {
        activation = true;
    } else if ("length".equals(name)) {
        if (token == Token.GETPROP
            && compilerEnv.getLanguageVersion() == Context.VERSION_1_2)
        {
            // Use of "length" in 1.2 requires an activation object.
            activation = true;
        }
    }
    if (activation) {
        setRequiresActivation();
    }
}
 

public final void transform(ScriptNode tree)
{
    transformCompilationUnit(tree);
    for (int i = 0; i != tree.getFunctionCount(); ++i) {
        FunctionNode fn = tree.getFunctionNode(i);
        transform(fn);
    }
}
 

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;
    if (!noParen) {
        decompiler.addToken(Token.LP);
    }
    List<AstNode> params = fn.getParams();
    for (int i = 0; i < params.size(); i++) {
        decompile(params.get(i));
        if (i < params.size() - 1) {
            decompiler.addToken(Token.COMMA);
        }
    }
    if (!noParen) {
        decompiler.addToken(Token.RP);
    }
    if (isArrow) {
        decompiler.addToken(Token.ARROW);
    }
    if (!fn.isExpressionClosure()) {
        decompiler.addEOL(Token.LC);
    }
    return mexpr;
}
 

int markFunctionStart(int functionType)
{
    int savedOffset = getCurrentOffset();
    if (functionType != FunctionNode.ARROW_FUNCTION) {
        addToken(Token.FUNCTION);
        append((char)functionType);
    }
    return savedOffset;
}
 

/**
 * find the function definition that immediately surrounds a given AST node.
 * Returns null if there is no surrounding function.
 *
 */
public static FunctionNode findEnclosingFunction(AstNode node) {
	AstNode current = node;
	while (current != null && !(current instanceof FunctionNode)){
		current = current.getParent();
	}
	FunctionNode fun = (FunctionNode)current;
	return fun;
}
 

/**
 * Finds the declaration of the called function. Assumes that the call's target
 * is a Name, which is passed as the second parameter.
 *
 */
static FunctionNode findFunDecl(FunctionCall fc, Name funName){
	List<FunctionNode> funsFound = findFunDecl2(fc, new ArrayList<FunctionNode>());
	for (int i=0; i < funsFound.size(); i++){
		FunctionNode fun = funsFound.get(i);
		if (funName.getIdentifier().equals(fun.getName())){
			return fun;
		}
	}
	return null;
}
 

@Override
public boolean visit(AstNode node) {
	if (isThis(node)){
		AstNode current = node;
		while (!(current instanceof FunctionNode)){
			current = current.getParent();
		}
		if (current == this.fun){
			refersToThis = true;
		}
	}
	return true;
}
 

private void arrowFunctionParams(FunctionNode fnNode, AstNode params, Map<String, Node> destructuring, Set<String> paramNames) {
    if (params instanceof ArrayLiteral || params instanceof ObjectLiteral) {
        markDestructuring(params);
        fnNode.addParam(params);
        String pname = currentScriptOrFn.getNextTempName();
        defineSymbol(Token.LP, pname, false);
        destructuring.put(pname, params);
    } else if (params instanceof InfixExpression && params.getType() == Token.COMMA) {
        arrowFunctionParams(fnNode, ((InfixExpression)params).getLeft(), destructuring, paramNames);
        arrowFunctionParams(fnNode, ((InfixExpression)params).getRight(), destructuring, paramNames);
    } else if (params instanceof Name) {
        fnNode.addParam(params);
        String paramName = ((Name)params).getIdentifier();
        defineSymbol(Token.LP, paramName);

        if (this.inUseStrictDirective) {
            if ("eval".equals(paramName) ||
                "arguments".equals(paramName))
                {
                    reportError("msg.bad.id.strict", paramName);
                }
            if (paramNames.contains(paramName))
                addError("msg.dup.param.strict", paramName);
            paramNames.add(paramName);
        }
    } else {
        reportError("msg.no.parm", params.getPosition(), params.getLength());
        fnNode.addParam(makeErrorNode());
    }
}
 

public final void transform(ScriptNode tree, boolean inStrictMode)
{
    inStrictMode = inStrictMode || tree.isInStrictMode();
    transformCompilationUnit(tree, inStrictMode);
    for (int i = 0; i != tree.getFunctionCount(); ++i) {
        FunctionNode fn = tree.getFunctionNode(i);
        transform(fn, inStrictMode);
    }
}
 

private static void toStringTreeHelper(ScriptNode treeTop, Node n,
                                       ObjToIntMap printIds,
                                       int level, StringBuilder sb)
{
    if (Token.printTrees) {
        if (printIds == null) {
            printIds = new ObjToIntMap();
            generatePrintIds(treeTop, printIds);
        }
        for (int i = 0; i != level; ++i) {
            sb.append("    ");
        }
        n.toString(printIds, sb);
        sb.append('\n');
        for (Node cursor = n.getFirstChild(); cursor != null;
             cursor = cursor.getNext())
        {
            if (cursor.getType() == Token.FUNCTION) {
                int fnIndex = cursor.getExistingIntProp(Node.FUNCTION_PROP);
                FunctionNode fn = treeTop.getFunctionNode(fnIndex);
                toStringTreeHelper(fn, fn, null, level + 1, sb);
            } else {
                toStringTreeHelper(treeTop, cursor, printIds, level+1, sb);
            }
        }
    }
}
 

private ObjectProperty methodDefinition(int pos, AstNode propName, int entryKind)
    throws IOException
{
    FunctionNode fn = function(FunctionNode.FUNCTION_EXPRESSION);
    // We've already parsed the function name, so fn should be anonymous.
    Name name = fn.getFunctionName();
    if (name != null && name.length() != 0) {
        reportError("msg.bad.prop");
    }
    ObjectProperty pn = new ObjectProperty(pos);
    switch (entryKind) {
    case GET_ENTRY:
        pn.setIsGetterMethod();
        fn.setFunctionIsGetterMethod();
        break;
    case SET_ENTRY:
        pn.setIsSetterMethod();
        fn.setFunctionIsSetterMethod();
        break;
    case METHOD_ENTRY:
        pn.setIsNormalMethod();
        fn.setFunctionIsNormalMethod();
        break;
    }
    int end = getNodeEnd(fn);
    pn.setLeft(propName);
    pn.setRight(fn);
    pn.setLength(end - pos);
    return pn;
}
 

private static void toStringTreeHelper(ScriptNode treeTop, Node n,
                                       ObjToIntMap printIds,
                                       int level, StringBuffer sb)
{
    if (Token.printTrees) {
        if (printIds == null) {
            printIds = new ObjToIntMap();
            generatePrintIds(treeTop, printIds);
        }
        for (int i = 0; i != level; ++i) {
            sb.append("    ");
        }
        n.toString(printIds, sb);
        sb.append('\n');
        for (Node cursor = n.getFirstChild(); cursor != null;
             cursor = cursor.getNext())
        {
            if (cursor.getType() == Token.FUNCTION) {
                int fnIndex = cursor.getExistingIntProp(Node.FUNCTION_PROP);
                FunctionNode fn = treeTop.getFunctionNode(fnIndex);
                toStringTreeHelper(fn, fn, null, level + 1, sb);
            } else {
                toStringTreeHelper(treeTop, cursor, printIds, level+1, sb);
            }
        }
    }
}
 

/**
 * For a {@link FunctionNode} representing a constructor, if the constructor C is
 * followed by a sequence of assignments of the form C.prototype.a = ...;, return
 * a set of all the properties written on the prototype.  If the assignments do not
 * fit that form, return the empty set.
 * @param consNode
 * @return
 */
public static Set<String> getWrittenPrototypeProps(FunctionNode consNode) {
    Set<String> result = HashSetFactory.make();
    AstNode parent = consNode.getParent();
    boolean found = false;
    for (Node child: parent) {
        if (child instanceof EmptyStatement) {
            continue;
        }
        if (child.equals(consNode)) {
            found = true;
        } else if (found) {
            // looking for a statement of the form C.prototype.a = ...;
            boolean foundAssign = false;
            if (child instanceof ExpressionStatement) {
                AstNode expression = ((ExpressionStatement)child).getExpression();
                if (expression instanceof Assignment) {
                    Assignment assign = (Assignment) expression;
                    AstNode lhs = assign.getLeft();
                    if (lhs instanceof PropertyGet) {
                        PropertyGet pg = (PropertyGet) lhs;
                        AstNode pgTarget = pg.getTarget();
                        if (pgTarget instanceof PropertyGet) {
                            PropertyGet basePG = (PropertyGet) pgTarget;
                            if (basePG.getProperty().getIdentifier().equals("prototype")) {
                                // BINGO
                                result.add(pg.getProperty().getIdentifier());
                                foundAssign = true;
                            }
                        }
                    }
                }
            }
            if (!foundAssign) {
                // stop looking for more assignments
                break;
            }
        }
    }
    return result;
}
 

public static boolean isMethodAssignedInObjectLiteral(FunctionNode n){
	return (n.getParent() instanceof ObjectProperty && n.getParent().getParent() instanceof ObjectLiteral);
}
 

/**
 * This method generates constraints for all relevant AstNodes. It delegates its work to various
 * processXXX() methods that handle AstNodes of type XXX.
 */
@Override
public boolean visit(AstNode node) {
	if (node instanceof VariableInitializer){
		processVariableInitializer(node);
	} else if (node instanceof ReturnStatement){
		processReturnStatement((ReturnStatement)node);
	} else if (node instanceof ExpressionStatement){
		processExpressionStatement((ExpressionStatement)node);
	} else if (node instanceof ForLoop){
		processForLoop((ForLoop)node);
	} else if (node instanceof ForInLoop){
		processForInLoop((ForInLoop)node);
	}else if (node instanceof WhileLoop){
		processWhileLoop((WhileLoop)node);
	} else if (node instanceof DoLoop){
		processDoLoop((DoLoop)node);
	} else if (node instanceof NewExpression){
		processNewExpression((NewExpression)node);
	} else if (node instanceof FunctionCall){
		processFunctionCall((FunctionCall)node);
	} else if (node instanceof ElementGet){
		processElementGet((ElementGet)node);
	} else if (node instanceof FunctionNode){
		processFunctionNode((FunctionNode)node);
	} else if (node instanceof IfStatement){
		processIfStatement((IfStatement)node);
	} else if (node instanceof KeywordLiteral){
		processKeywordLiteral((KeywordLiteral)node);
	} else if (node instanceof SwitchStatement){
		processSwitchStatement((SwitchStatement)node);
	} else if (node instanceof SwitchCase){
		processSwitchCase((SwitchCase)node);
	} else if ((node instanceof AstRoot) || //AstRoot: no constraints need to be generated
		(node instanceof BreakStatement) || //BreakStatement: no constraints need to be generated
		(node instanceof VariableDeclaration) || //VariableDeclaration: we generate constraints for its constituent VariableInitializer nodes
		(node instanceof Name) || //Name: generate constraints for complex expressions that refer to names
		(node instanceof NumberLiteral) || //NumberLiteral: generate constraints for complex expressions that refer to names
		(node instanceof StringLiteral) || //StringLiteral: generate constraints for complex expressions that refer to names
		(node instanceof Assignment) || // Assignment is a special case of InfixExpression
		(node instanceof ArrayLiteral) ||
		(node instanceof UnaryExpression) ||
		(node instanceof InfixExpression) ||
		(node instanceof ConditionalExpression) ||
		(node instanceof ParenthesizedExpression) ||
		(node instanceof EmptyExpression) ||
		(node instanceof ObjectLiteral) ||
		(node instanceof EmptyStatement) ||
		(node instanceof ContinueStatement) ||
		(node instanceof Scope) ||
		(node instanceof Block)){ // // occurs in programs with for loops -- nothing to be done here?
		/* nothing */
	} else {
		error("unsupported node " + node.toSource().trim() + " of type: " + node.getClass().getName(), node);
	}
	return true;
}
 

private Node transformGenExpr(GeneratorExpression node) {
    Node pn;
    
    FunctionNode fn = new FunctionNode();
    fn.setSourceName(currentScriptOrFn.getNextTempName());
    fn.setIsGenerator();
    fn.setFunctionType(FunctionNode.FUNCTION_EXPRESSION);
    fn.setRequiresActivation();
  
    int functionType = fn.getFunctionType();
    int start = decompiler.markFunctionStart(functionType);
    Node mexpr = decompileFunctionHeader(fn);
    int index = currentScriptOrFn.addFunction(fn);

    PerFunctionVariables savedVars = new PerFunctionVariables(fn);
    try {
        // If we start needing to record much more codegen metadata during
        // function parsing, we should lump it all into a helper class.
        Node destructuring = (Node)fn.getProp(Node.DESTRUCTURING_PARAMS);
        fn.removeProp(Node.DESTRUCTURING_PARAMS);

        int lineno = node.lineno;
        ++nestingOfFunction;  // only for body, not params
        Node body = genExprTransformHelper(node);

        if (!fn.isExpressionClosure()) {
            decompiler.addToken(Token.RC);
        }
        fn.setEncodedSourceBounds(start, decompiler.markFunctionEnd(start));

        if (functionType != FunctionNode.FUNCTION_EXPRESSION && !fn.isExpressionClosure()) {
            // Add EOL only if function is not part of expression
            // since it gets SEMI + EOL from Statement in that case
            decompiler.addToken(Token.EOL);
        }

        if (destructuring != null) {
            body.addChildToFront(new Node(Token.EXPR_VOID,
                                          destructuring, lineno));
        }

        int syntheticType = fn.getFunctionType();
        pn = initFunction(fn, index, body, syntheticType);
        if (mexpr != null) {
            pn = createAssignment(Token.ASSIGN, mexpr, pn);
            if (syntheticType != FunctionNode.FUNCTION_EXPRESSION) {
                pn = createExprStatementNoReturn(pn, fn.getLineno());
            }
        }
    } finally {
        --nestingOfFunction;
        savedVars.restore();
    }
   
    Node call = createCallOrNew(Token.CALL, pn);
    call.setLineno(node.getLineno());
    decompiler.addToken(Token.LP);
    decompiler.addToken(Token.RP);
    return call;
}
 

/**
 * assignment to the "prototype" property
 */
private void processAssignToPrototype(Assignment a, AstNode left, AstNode right, ITypeTerm expTerm) throws Error {
	PropertyGet pg = (PropertyGet)left;
	AstNode base = pg.getTarget();
	ITypeTerm pgTerm = findOrCreateExpressionTerm(pg);
	if (base instanceof Name){
		Name name = (Name)base;
		if (!validRHSForAssignToPrototype(right)) {
			error(
					"expression "
							+ right.toSource()
							+ " cannot be assigned to a constructor prototype (line "
							+ right.getLineno() + ")", a);
		}
		// can only write to prototype immediately after declaration of
		// constructor of the same name
		AstNode parent = a.getParent();
		if (!(parent instanceof ExpressionStatement)) {
			error(
					"assignment to prototype property not allowed here (line "
							+ a.getLineno() + ")", a);
			return;
		}
		Node prev = getPredecessorNode(parent);
		if (!(prev instanceof FunctionNode)) {
			error(
					"assignment to prototype property only allowed after constructor declaration (line "
							+ a.getLineno() + ")", a);
			return;
		}
		FunctionNode fn = (FunctionNode) prev;
		String functionName = fn.getName();
		String identifier = name.getIdentifier();
		if (!functionName.equals(identifier)) {
			error(
					"can only assign to prototype of function "
							+ functionName + " here (line " + a.getLineno()
							+ ")", a);
			return;
		}
		ITypeTerm baseTerm = findOrCreateExpressionTerm(base); // make term for expression
		ITypeTerm nameTerm = findOrCreateNameDeclarationTerm(name); // find unique representative for referenced Name
		addTypeEqualityConstraint(baseTerm, nameTerm, a.getLineno(), null); // equate them
		ITypeTerm protoTerm = findOrCreateProtoTerm(baseTerm, pg.getLineno());
		ITypeTerm rightTerm = processExpression(right);
		addTypeEqualityConstraint(pgTerm, protoTerm, a.getLineno(), null);
		addTypeEqualityConstraint(rightTerm, protoTerm, a.getLineno(), null);
		addTypeEqualityConstraint(expTerm, protoTerm, a.getLineno(), null);
	} else {
		error("processAssignToPrototype: unsupported case for receiver expression: " + base.getClass().getName(), base);
	}
}