private void CombineTwoExpressions(Block node, int ndx)
{
var prevBinary = node[ndx - 1] as BinaryOperator;
var curBinary = node[ndx] as BinaryOperator;
Lookup lookup;
if (prevBinary != null
&& curBinary != null
&& prevBinary.IsAssign
&& curBinary.IsAssign
&& curBinary.OperatorToken != JSToken.Assign
&& (lookup = curBinary.Operand1 as Lookup) != null
&& prevBinary.Operand1.IsEquivalentTo(curBinary.Operand1))
{
if (prevBinary.OperatorToken == JSToken.Assign)
{
// transform: lookup=expr1;lookup[OP]=expr2; ==> lookup=expr1[OP]expr2
var binOp = new BinaryOperator(prevBinary.Operand2.Context.Clone().CombineWith(curBinary.Operand2.Context), prevBinary.Parser)
{
Operand1 = prevBinary.Operand2,
Operand2 = curBinary.Operand2,
OperatorToken = JSScanner.StripAssignment(curBinary.OperatorToken),
OperatorContext = curBinary.OperatorContext
};
prevBinary.Operand2 = binOp;
// we are removing the second lookup, so clean up the reference on the field
if (lookup.VariableField != null)
{
lookup.VariableField.References.Remove(lookup);
}
// and remove the current assignment expression (everything was combined into the previous)
node[ndx] = null;
}
else
{
// there's lots of ins-and-outs in terms of strings versus numerics versus precedence and all
// sorts of stuff. I need to iron this out a little better, but until then, just combine with a comma.
// transform: expr1;expr2 ==> expr1,expr2
var binOp = CommaOperator.CombineWithComma(prevBinary.Context.Clone().CombineWith(curBinary.Context), m_parser, prevBinary, curBinary);
// replace the previous node and delete the current
node[ndx - 1] = binOp;
node[ndx] = null;
}
}
else
{
// transform: expr1;expr2 to expr1,expr2
// use the special comma operator object so we can handle it special
// and don't create stack-breakingly deep trees
var binOp = CommaOperator.CombineWithComma(node[ndx - 1].Context.Clone().CombineWith(node[ndx].Context), m_parser, node[ndx - 1], node[ndx]);
// replace the current node and delete the previous
node[ndx] = binOp;
node[ndx - 1] = null;
}
}
public override void Visit(Block node)
{
if (node != null)
{
// javascript doesn't have block scope, so there really is no point
// in nesting blocks. Unnest any now, before we start combining var statements
UnnestBlocks(node);
if (m_combineAdjacentVars)
{
// look at the statements in the block.
// if there are multiple var statements adjacent to each other, combine them.
// walk BACKWARDS down the list because we'll be removing items when we encounter
// multiple vars, etc.
// we also don't need to check the first one, since there is nothing before it.
for (int ndx = node.Count - 1; ndx > 0; --ndx)
{
// if the previous node is not a Var, then we don't need to try and combine
// it with the current node
var previousVar = node[ndx - 1] as Var;
if (previousVar != null && node[ndx] is Var)
{
// add the items in this VAR to the end of the previous
previousVar.Append(node[ndx]);
// delete this item from the block
node.RemoveAt(ndx);
}
else
{
// do the same thing for lexical declarations
var previousLex = node[ndx - 1] as LexicalDeclaration;
var thisLex = node[ndx] as LexicalDeclaration;
if (previousLex != null && thisLex != null)
{
// but we can only combine them if they are the same type (let or const)
if (previousLex.StatementToken == thisLex.StatementToken)
{
previousLex.Append(node[ndx]);
node.RemoveAt(ndx);
}
}
else
{
// try doing the same for const-statements: combine adjacent ones
var previousConst = node[ndx - 1] as ConstStatement;
if (previousConst != null && node[ndx] is ConstStatement)
{
// they are both ConstStatements, so adding the current one to the
// previous one will combine them, then delete the latter one.
previousConst.Append(node[ndx]);
node.RemoveAt(ndx);
}
}
}
}
}
// recurse down the tree after we've combined the adjacent var statements
base.Visit(node);
}
}
public void Visit(Block node)
{
if (node != null && node.Count > 0)
{
// there should only be one "statement"
node[0].Accept(this);
}
}
private static int RelocateDirectivePrologue(Block block, int insertAt, DirectivePrologue directivePrologue)
{
// skip over any important comments
while (insertAt < block.Count && (block[insertAt] is ImportantComment))
{
++insertAt;
}
// if the one we want to insert is already at this spot, then we're good to go
if (block[insertAt] != directivePrologue)
{
// remove it from where it is right now and insert it into the proper location
directivePrologue.Parent.ReplaceChild(directivePrologue, null);
block.Insert(insertAt, directivePrologue);
}
// and move up to the next slot
return ++insertAt;
}
private static int RelocateVar(Block block, int insertAt, Var varStatement)
{
// if the var statement is at the next position to insert, then we don't need
// to do anything.
if (block[insertAt] != varStatement)
{
// check to see if the current position is a var and we are the NEXT statement.
// if that's the case, we don't need to break out the initializer, just append all the
// vardecls as-is to the current position.
var existingVar = block[insertAt] as Var;
if (existingVar != null && block[insertAt + 1] == varStatement)
{
// just append our vardecls to the insertion point, then delete our statement
existingVar.Append(varStatement);
block.RemoveAt(insertAt + 1);
}
else
{
// iterate through the decls and count how many have initializers
var initializerCount = 0;
for (var ndx = 0; ndx < varStatement.Count; ++ndx)
{
if (varStatement[ndx].Initializer != null)
{
++initializerCount;
}
}
// if there are more than two decls with initializers, then we won't actually
// be gaining anything by moving the var to the top. We'll get rid of the four
// bytes for the "var ", but we'll be adding two bytes for the name and comma
// because name=init will still need to remain behind.
if (initializerCount <= 2)
{
// first iterate through all the declarations in the var statement,
// constructing an expression statement that is made up of assignment
// operators for each of the declarations that have initializers (if any)
// and removing all the initializers
var assignments = new List<AstNode>();
for (var ndx = 0; ndx < varStatement.Count; ++ndx)
{
var varDecl = varStatement[ndx];
if (varDecl.Initializer != null)
{
if (varDecl.IsCCSpecialCase)
{
// create a vardecl with the same name and no initializer
var copyDecl = new VariableDeclaration(varDecl.Context, varDecl.Parser)
{
Identifier = varDecl.Identifier,
NameContext = varDecl.VariableField.OriginalContext,
VariableField = varDecl.VariableField
};
// replace the special vardecl with the copy
varStatement[ndx] = copyDecl;
// add the original vardecl to the list of "assignments"
assignments.Add(varDecl);
// add the new decl to the field's declaration list, and remove the old one
// because we're going to change that to an assignment.
varDecl.VariableField.Declarations.Add(copyDecl);
varDecl.VariableField.Declarations.Remove(varDecl);
}
else
{
// hold on to the object so we don't lose it to the GC
var initializer = varDecl.Initializer;
// remove it from the vardecl
varDecl.Initializer = null;
// create an assignment operator for a lookup to the name
// as the left, and the initializer as the right, and add it to the list
var lookup = new Lookup(varDecl.VariableField.OriginalContext, varDecl.Parser)
{
Name = varDecl.Identifier,
VariableField = varDecl.VariableField,
};
assignments.Add(new BinaryOperator(varDecl.Context, varDecl.Parser)
{
Operand1 = lookup,
Operand2 = initializer,
OperatorToken = JSToken.Assign,
OperatorContext = varDecl.AssignContext
});
// add the new lookup to the field's references
varDecl.VariableField.References.Add(lookup);
}
}
}
// now if there were any initializers...
if (assignments.Count > 0)
{
// we want to create one big expression from all the assignments and replace the
// var statement with the assignment(s) expression. Start at position n=1 and create
// a binary operator of n-1 as the left, n as the right, and using a comma operator.
var expression = assignments[0];
for (var ndx = 1; ndx < assignments.Count; ++ndx)
{
expression = CommaOperator.CombineWithComma(null, expression.Parser, expression, assignments[ndx]);
}
// replace the var with the expression.
// we still have a pointer to the var, so we can insert it back into the proper
// place next.
varStatement.Parent.ReplaceChild(varStatement, expression);
}
else
{
// no initializers.
// if the parent is a for-in statement...
var forInParent = varStatement.Parent as ForIn;
if (forInParent != null)
{
// we want to replace the var statement with a lookup for the var
// there should be only one vardecl
var varDecl = varStatement[0];
var lookup = new Lookup(varDecl.VariableField.OriginalContext, varStatement.Parser)
{
Name = varDecl.Identifier,
VariableField = varDecl.VariableField
};
varStatement.Parent.ReplaceChild(varStatement, lookup);
varDecl.VariableField.References.Add(lookup);
}
else
{
// just remove the var statement altogether
varStatement.Parent.ReplaceChild(varStatement, null);
}
}
// if the statement at the insertion point is a var-statement already,
// then we just need to append our vardecls to it. Otherwise we'll insert our
// var statement at the right point
if (existingVar != null)
{
// append the varstatement we want to move to the existing var, which will
// transfer all the vardecls to it.
existingVar.Append(varStatement);
}
else
{
// move the var to the insert point, incrementing the position or next time
block.Insert(insertAt, varStatement);
}
}
}
}
return insertAt;
}
/// <summary>
/// Parse the source code using the given settings, getting back an abstract syntax tree Block node as the root
/// representing the list of statements in the source code.
/// </summary>
/// <param name="settings">code settings to use to process the source code</param>
/// <returns>root Block node representing the top-level statements</returns>
public Block Parse(CodeSettings settings)
{
// initialize the scanner with our settings
// make sure the RawTokens setting is OFF or we won't be able to create our AST
InitializeScanner(settings);
// make sure we initialize the global scope's strict mode to our flag, whether or not it
// is true. This means if the setting is false, we will RESET the flag to false if we are
// reusing the scope and a previous Parse call had code that set it to strict with a
// program directive.
GlobalScope.UseStrict = m_settings.StrictMode;
// make sure the global scope knows about our known global names
GlobalScope.SetAssumedGlobals(m_settings);
// start of a new module
m_newModule = true;
Block scriptBlock;
Block returnBlock;
switch (m_settings.SourceMode)
{
case JavaScriptSourceMode.Program:
// simply parse a block of statements
returnBlock = scriptBlock = ParseStatements();
break;
case JavaScriptSourceMode.Expression:
// create a block, get the first token, add in the parse of a single expression,
// and we'll go fron there.
returnBlock = scriptBlock = new Block(CurrentPositionContext(), this);
GetNextToken();
try
{
var expr = ParseExpression();
if (expr != null)
{
scriptBlock.Append(expr);
scriptBlock.UpdateWith(expr.Context);
}
}
catch (EndOfFileException)
{
Debug.WriteLine("EOF");
}
break;
case JavaScriptSourceMode.EventHandler:
// we're going to create the global block, add in a function expression with a single
// parameter named "event", and then we're going to parse the input as the body of that
// function expression. We're going to resolve the global block, but only return the body
// of the function.
scriptBlock = new Block(null, this);
var parameters = new AstNodeList(null, this);
parameters.Append(new ParameterDeclaration(null, this)
{
Name = "event",
RenameNotAllowed = true
});
var funcExpression = new FunctionObject(null, this)
{
FunctionType = FunctionType.Expression,
ParameterDeclarations = parameters
};
scriptBlock.Append(funcExpression);
returnBlock = ParseStatements();
funcExpression.Body = returnBlock;
break;
default:
Debug.Fail("Unexpected source mode enumeration");
return null;
}
// resolve everything
ResolutionVisitor.Apply(scriptBlock, GlobalScope, m_settings);
if (scriptBlock != null && Settings.MinifyCode)
{
// this visitor doesn't just reorder scopes. It also combines the adjacent var variables,
// unnests blocks, identifies prologue directives, and sets the strict mode on scopes.
ReorderScopeVisitor.Apply(scriptBlock, this);
// analyze the entire node tree (needed for hypercrunch)
// root to leaf (top down)
var analyzeVisitor = new AnalyzeNodeVisitor(this);
scriptBlock.Accept(analyzeVisitor);
// analyze the scope chain (also needed for hypercrunch)
// root to leaf (top down)
m_globalScope.AnalyzeScope();
// if we want to crunch any names....
if (m_settings.LocalRenaming != LocalRenaming.KeepAll
&& m_settings.IsModificationAllowed(TreeModifications.LocalRenaming))
{
// then do a top-down traversal of the scope tree. For each field that had not
// already been crunched (globals and outers will already be crunched), crunch
// the name with a crunch iterator that does not use any names in the verboten set.
m_globalScope.AutoRenameFields();
}
// if we want to evaluate literal expressions, do so now
if (m_settings.EvalLiteralExpressions)
{
var visitor = new EvaluateLiteralVisitor(this);
scriptBlock.Accept(visitor);
}
// if any of the conditions we check for in the final pass are available, then
// make the final pass
if (m_settings.IsModificationAllowed(TreeModifications.BooleanLiteralsToNotOperators))
{
var visitor = new FinalPassVisitor(this);
scriptBlock.Accept(visitor);
}
// we want to walk all the scopes to make sure that any generated
// variables that haven't been crunched have been assigned valid
// variable names that don't collide with any existing variables.
m_globalScope.ValidateGeneratedNames();
}
if (returnBlock.Parent != null)
{
returnBlock.Parent = null;
}
return returnBlock;
}
//
// statements (we should only hit expressions)
//
public void Visit(Block node)
{
Debug.Fail("shouldn't get here");
}
public override void Visit(Block node)
{
if (node != null)
{
// if this block has a block scope, then look at the lexically-declared names (if any)
// and throw an error if any are defined as var's within this scope (ES6 rules).
// if this is the body of a function object, use the function scope.
ActivationObject lexicalScope = node.BlockScope;
if (lexicalScope == null)
{
var functionObject = node.Parent as FunctionObject;
if (functionObject != null)
{
lexicalScope = functionObject.FunctionScope;
}
}
if (lexicalScope != null)
{
foreach (var lexDecl in lexicalScope.LexicallyDeclaredNames)
{
var varDecl = lexicalScope.VarDeclaredName(lexDecl.Name);
if (varDecl != null)
{
// collision.
// if the lexical declaration is a let or const declaration (as opposed to a function declaration),
// then force the warning to an error. This is so the function declaration will remain a warning if
// it collides with a var.
varDecl.NameContext.HandleError(JSError.DuplicateLexicalDeclaration, lexDecl is LexicalDeclaration);
// mark them both a no-rename to preserve the collision in the output
lexDecl.VariableField.IfNotNull(v => v.CanCrunch = false);
varDecl.VariableField.IfNotNull(v => v.CanCrunch = false);
}
}
}
// we might things differently if these statements are the body collection for a function
// because we can assume the implicit return statement at the end of it
bool isFunctionLevel = (node.Parent is FunctionObject);
// if we want to remove debug statements...
if (m_parser.Settings.StripDebugStatements && m_parser.Settings.IsModificationAllowed(TreeModifications.StripDebugStatements))
{
// do it now before we try doing other things
StripDebugStatements(node);
}
// analyze all the statements in our block and recurse them
if (node.BlockScope != null)
{
m_scopeStack.Push(node.BlockScope);
}
try
{
// don't call the base class to recurse -- let's walk the block
// backwards in case any of the children opt to delete themselves.
for (var ndx = node.Count - 1; ndx >= 0; --ndx)
{
node[ndx].Accept(this);
}
}
finally
{
if (node.BlockScope != null)
{
m_scopeStack.Pop();
}
}
if (m_parser.Settings.RemoveUnneededCode)
{
// go forward, and check the count each iteration because we might be ADDING statements to the block.
// let's look at all our if-statements. If a true-clause ends in a return, then we don't
// need the else-clause; we can pull its statements out and stick them after the if-statement.
// also, if we encounter a return-, break- or continue-statement, we can axe everything after it
for (var ndx = 0; ndx < node.Count; ++ndx)
{
// see if it's an if-statement with both a true and a false block
var ifNode = node[ndx] as IfNode;
if (ifNode != null
&& ifNode.TrueBlock != null
&& ifNode.TrueBlock.Count > 0
&& ifNode.FalseBlock != null)
{
// now check to see if the true block ends in a return statement
if (ifNode.TrueBlock[ifNode.TrueBlock.Count - 1] is ReturnNode)
{
// transform: if(cond){statements1;return}else{statements2} to if(cond){statements1;return}statements2
// it does. insert all the false-block statements after the if-statement
node.InsertRange(ndx + 1, ifNode.FalseBlock.Children);
// and then remove the false block altogether
ifNode.FalseBlock = null;
}
}
else if (node[ndx] is ReturnNode
|| node[ndx] is Break
|| node[ndx] is ContinueNode
|| node[ndx] is ThrowNode)
{
// we have an exit node -- no statments afterwards will be executed, so clear them out.
// transform: {...;return;...} to {...;return}
// transform: {...;break;...} to {...;break}
// transform: {...;continue;...} to {...;continue}
// transform: {...;throw;...} to {...;throw}
// we've found an exit statement, and it's not the last statement in the function.
// walk the rest of the statements and delete anything that isn't a function declaration
// or a var- or const-statement.
for (var ndxRemove = node.Count - 1; ndxRemove > ndx; --ndxRemove)
{
var funcObject = node[ndxRemove] as FunctionObject;
if (funcObject == null || funcObject.FunctionType != FunctionType.Declaration)
{
// if it's a const-statement, leave it.
// we COULD check to see if the constant is referenced anywhere and delete
// any that aren't. Maybe later.
// we also don't want to do like the var-statements and remove the initializers.
// Not sure if any browsers would fail a const WITHOUT an initializer.
if (!(node[ndxRemove] is ConstStatement))
{
var varStatement = node[ndxRemove] as Var;
if (varStatement != null)
{
// var statements can't be removed, but any initializers should
// be deleted since they won't get executed.
for (var ndxDecl = 0; ndxDecl < varStatement.Count; ++ndxDecl)
{
if (varStatement[ndxDecl].Initializer != null)
{
varStatement[ndxDecl].Initializer = null;
}
}
}
else
{
// not a function declaration, and not a var statement -- get rid of it
DetachReferences.Apply(node[ndxRemove]);
node.RemoveAt(ndxRemove);
}
}
}
}
}
}
}
// now check the last statement -- if it's an if-statement where the true-block is a single return
// and there is no false block, convert this one statement to a conditional. We might back it out later
// if we don't combine the conditional with other stuff.
// but we can only do this if we're at the functional level because of the implied return at the end
// of that block.
if (isFunctionLevel && node.Count > 0
&& m_parser.Settings.IsModificationAllowed(TreeModifications.IfConditionReturnToCondition))
{
ReturnNode returnNode;
var ifNode = FindLastStatement(node) as IfNode;
if (ifNode != null && ifNode.FalseBlock == null
&& ifNode.TrueBlock.Count == 1
&& (returnNode = ifNode.TrueBlock[0] as ReturnNode) != null)
{
// if the return node doesn't have an operand, then we can just replace the if-statement with its conditional
if (returnNode.Operand == null)
{
// if the condition is a constant, then eliminate it altogether
if (ifNode.Condition.IsConstant)
{
// delete the node altogether. Because the condition is a constant,
// there is no else-block, and the if-block only contains a return
// with no expression, we don't have anything to detach.
node.ReplaceChild(ifNode, null);
}
else
{
// transform: {...;if(cond)return;} to {...;cond;}
node.ReplaceChild(ifNode, ifNode.Condition);
}
}
else if (returnNode.Operand.IsExpression)
{
// this is a strategic replacement that might pay off later. And if
// it doesn't, we'll eventually back it out after all the other stuff
// if applied on top of it.
// transform: if(cond)return expr;} to return cond?expr:void 0}
var conditional = new Conditional(null, m_parser)
{
Condition = ifNode.Condition,
TrueExpression = returnNode.Operand,
FalseExpression = CreateVoidNode()
};
// replace the if-statement with the new return node
node.ReplaceChild(ifNode, new ReturnNode(ifNode.Context, m_parser)
{
Operand = conditional
});
Optimize(conditional);
}
}
}
// now walk through and combine adjacent expression statements, and adjacent var-for statements
// and adjecent expression-return statements
if (m_parser.Settings.IsModificationAllowed(TreeModifications.CombineAdjacentExpressionStatements))
{
CombineExpressions(node);
}
// check to see if we want to combine a preceding var with a for-statement
if (m_parser.Settings.IsModificationAllowed(TreeModifications.MoveVarIntoFor))
{
// look at the statements in the block.
// walk BACKWARDS down the list because we'll be removing items when we encounter
// var statements that can be moved inside a for statement's initializer
// we also don't need to check the first one, since there is nothing before it.
for (int ndx = node.Count - 1; ndx > 0; --ndx)
{
// see if the previous statement is a var statement
// (we've already combined adjacent var-statements)
ForNode forNode;
WhileNode whileNode;
var previousVar = node[ndx - 1] as Var;
if (previousVar != null && (forNode = node[ndx] as ForNode) != null)
{
// BUT if the var statement has any initializers containing an in-operator, first check
// to see if we haven't killed that move before we try moving it. Opera 11 seems to have
// an issue with that syntax, even if properly parenthesized.
if (m_parser.Settings.IsModificationAllowed(TreeModifications.MoveInExpressionsIntoForStatement)
|| !previousVar.ContainsInOperator)
{
// and see if the forNode's initializer is empty
if (forNode.Initializer != null)
{
// not empty -- see if it is a Var node
Var varInitializer = forNode.Initializer as Var;
if (varInitializer != null)
{
// transform: var decls1;for(var decls2;...) to for(var decls1,decls2;...)
// we want to PREPEND the initializers in the previous var-statement
// to our for-statement's initializer var-statement list
varInitializer.InsertAt(0, previousVar);
// then remove the previous var statement
node.RemoveAt(ndx - 1);
// this will bump the for node up one position in the list, so the next iteration
// will be right back on this node in case there are other var statements we need
// to combine
}
else
{
// we want to see if the initializer expression is a series of one or more
// simple assignments to variables that are in the previous var statement.
// if all the expressions are assignments to variables that are defined in the
// previous var statement, then we can just move the var statement into the
// for statement.
var binaryOp = forNode.Initializer as BinaryOperator;
if (binaryOp != null && AreAssignmentsInVar(binaryOp, previousVar))
{
// transform: var decls;for(expr1;...) to for(var decls,expr1;...)
// WHERE expr1 only consists of assignments to variables that are declared
// in that previous var-statement.
// TODO: we *could* also do it is the expr1 assignments are to lookups that are
// defined in THIS scope (not any outer scopes), because it wouldn't hurt to have
// then in a var statement again.
// create a list and fill it with all the var-decls created from the assignment
// operators in the expression
var varDecls = new List<VariableDeclaration>();
ConvertAssignmentsToVarDecls(binaryOp, varDecls, m_parser);
// then go through and append each one to the var statement before us
foreach (var varDecl in varDecls)
{
previousVar.Append(varDecl);
}
// move the previous var-statement into our initializer
forNode.Initializer = previousVar;
// and remove the previous var-statement from the list.
node.RemoveAt(ndx - 1);
// this will bump the for node up one position in the list, so the next iteration
// will be right back on this node, but the initializer will not be null
}
}
}
else
{
// transform: var decls;for(;...) to for(var decls;...)
// if it's empty, then we're free to add the previous var statement
// to this for statement's initializer. remove it from it's current
// position and add it as the initializer
node.RemoveAt(ndx - 1);
forNode.Initializer = previousVar;
// this will bump the for node up one position in the list, so the next iteration
// will be right back on this node, but the initializer will not be null
}
}
}
else if (previousVar != null
&& (whileNode = node[ndx] as WhileNode) != null
&& m_parser.Settings.IsModificationAllowed(TreeModifications.ChangeWhileToFor))
{
// transform: var ...;while(cond)... => for(var ...;cond;)...
node[ndx] = new ForNode(null, m_parser)
{
Initializer = previousVar,
Condition = whileNode.Condition,
Body = whileNode.Body
};
node.RemoveAt(ndx - 1);
}
}
}
// see if the last statement is a return statement
ReturnNode lastReturn;
if ((lastReturn = FindLastStatement(node) as ReturnNode) != null)
{
// set this flag to true if we end up adding an expression to the block.
// before exiting, we'll go through and combine adjacent expressions again if this
// flag has been set to true.
bool changedStatementToExpression = false;
// get the index of the statement before the last return
// (skip over function decls and importand comments)
var indexPrevious = PreviousStatementIndex(node, lastReturn);
// just out of curiosity, let's see if we fit a common pattern:
// var name=expr;return name;
// or
// const name=expr;return name;
// if so, we can cut out the var and simply return the expression
Lookup lookup;
if ((lookup = lastReturn.Operand as Lookup) != null && indexPrevious >= 0)
{
// use the base class for both the var- and const-statements so we will
// pick them both up at the same time
var varStatement = node[indexPrevious] as Declaration;
if (varStatement != null)
{
// if the last vardecl in the var statement matches the return lookup, and no
// other references exist for this field (refcount == 1)...
VariableDeclaration varDecl;
if ((varDecl = varStatement[varStatement.Count - 1]).Initializer != null
&& varDecl.IsEquivalentTo(lookup)
&& varDecl.VariableField.RefCount == 1)
{
// clean up the field's references because we're removing both the lookup reference
// in the return statement and the vardecl.
varDecl.VariableField.References.Remove(lookup);
varDecl.VariableField.Declarations.Remove(varDecl);
if (varStatement.Count == 1)
{
// transform: ...;var name=expr;return name} to ...;return expr}
// there's only one vardecl in the var, so get rid of the entire statement
lastReturn.Operand = varDecl.Initializer;
node.RemoveAt(indexPrevious);
}
else
{
// multiple vardecls are in the statement; we only need to get rid of the last one
lastReturn.Operand = varDecl.Initializer;
varStatement[varStatement.Count - 1] = null;
}
}
}
}
// check to see if we can combine the return statement with a previous if-statement
// into a simple return-conditional. The true statement needs to have no false block,
// and only one statement in the true block.
Conditional conditional;
IfNode previousIf;
while (indexPrevious >= 0
&& lastReturn != null
&& (previousIf = node[indexPrevious] as IfNode) != null
&& previousIf.TrueBlock != null && previousIf.TrueBlock.Count == 1
&& previousIf.FalseBlock == null)
{
// assume no change is made for this loop
bool somethingChanged = false;
// and that one true-block statement needs to be a return statement
var previousReturn = previousIf.TrueBlock[0] as ReturnNode;
if (previousReturn != null)
{
if (lastReturn.Operand == null)
{
if (previousReturn.Operand == null)
{
// IF we are at the function level, then the block ends in an implicit return (undefined)
// and we can change this if to just the condition. If we aren't at the function level,
// then we have to leave the return, but we can replace the if with just the condition.
if (!isFunctionLevel)
{
// not at the function level, so the return must stay.
if (previousIf.Condition.IsConstant)
{
// transform: if(cond)return;return} to return}
node.RemoveAt(indexPrevious);
somethingChanged = true;
}
else
{
// transform: if(cond)return;return} to cond;return}
node[indexPrevious] = previousIf.Condition;
}
}
else if (previousIf.Condition.IsConstant)
{
// transform: remove if(cond)return;return} because cond is a constant
node.ReplaceChild(lastReturn, null);
node.RemoveAt(indexPrevious);
somethingChanged = true;
}
else
{
// transform: if(cond)return;return} to cond}
// replace the final return with just the condition, then remove the previous if
if (node.ReplaceChild(lastReturn, previousIf.Condition))
{
node.RemoveAt(indexPrevious);
somethingChanged = true;
}
}
}
else
{
// transform: if(cond)return expr;return} to return cond?expr:void 0
conditional = new Conditional(null, m_parser)
{
Condition = previousIf.Condition,
TrueExpression = previousReturn.Operand,
FalseExpression = CreateVoidNode()
};
// replace the final return with the new return, then delete the previous if-statement
if (node.ReplaceChild(lastReturn, new ReturnNode(null, m_parser)
{
Operand = conditional
}))
{
node.RemoveAt(indexPrevious);
Optimize(conditional);
somethingChanged = true;
}
}
}
else
{
if (previousReturn.Operand == null)
{
// transform: if(cond)return;return expr} to return cond?void 0:expr
conditional = new Conditional(null, m_parser)
{
Condition = previousIf.Condition,
TrueExpression = CreateVoidNode(),
FalseExpression = lastReturn.Operand
};
// replace the final return with the new return, then delete the previous if-statement
if (node.ReplaceChild(lastReturn, new ReturnNode(null, m_parser)
{
Operand = conditional
}))
{
node.RemoveAt(indexPrevious);
Optimize(conditional);
somethingChanged = true;
}
}
else if (previousReturn.Operand.IsEquivalentTo(lastReturn.Operand))
{
if (previousIf.Condition.IsConstant)
{
// the condition is constant, and the returns return the same thing.
// get rid of the if statement altogether.
// transform: if(cond)return expr;return expr} to return expr}
DetachReferences.Apply(previousReturn.Operand);
node.RemoveAt(indexPrevious);
somethingChanged = true;
}
else
{
// transform: if(cond)return expr;return expr} to return cond,expr}
// create a new binary op with the condition and the final-return operand,
// replace the operand on the final-return with the new binary operator,
// and then delete the previous if-statement
DetachReferences.Apply(previousReturn.Operand);
lastReturn.Operand = CommaOperator.CombineWithComma(null, m_parser, previousIf.Condition, lastReturn.Operand);
node.RemoveAt(indexPrevious);
somethingChanged = true;
}
}
else
{
// transform: if(cond)return expr1;return expr2} to return cond?expr1:expr2}
// create a new conditional with the condition and the return operands,
// replace the operand on the final-return with the new conditional operator,
// and then delete the previous if-statement
// transform: if(cond)return expr1;return expr2} to return cond?expr1:expr2}
conditional = new Conditional(null, m_parser)
{
Condition = previousIf.Condition,
TrueExpression = previousReturn.Operand,
FalseExpression = lastReturn.Operand
};
// replace the operand on the final-return with the new conditional operator,
// and then delete the previous if-statement
lastReturn.Operand = conditional;
node.RemoveAt(indexPrevious);
Optimize(conditional);
somethingChanged = true;
}
}
}
if (!somethingChanged)
{
// nothing changed -- break out of the loop
break;
}
else
{
// set the flag that indicates something changed in at least one of these loops
changedStatementToExpression = true;
// and since we changed something, we need to bump the index down one
// AFTER we grab the last return node (which has slipped into the same position
// as the previous node)
lastReturn = node[indexPrevious--] as ReturnNode;
}
}
// if we added any more expressions since we ran our expression-combination logic,
// run it again.
if (changedStatementToExpression
&& m_parser.Settings.IsModificationAllowed(TreeModifications.CombineAdjacentExpressionStatements))
{
CombineExpressions(node);
}
// and FINALLY, we want to see if what we did previously didn't pan out and we end
// in something like return cond?expr:void 0, in which case we want to change it
// back to a simple if(condition)return expr; (saves four bytes).
// see if the last statement is a return statement that returns a conditional
if (lastReturn != null
&& (conditional = lastReturn.Operand as Conditional) != null)
{
var unaryOperator = conditional.FalseExpression as UnaryOperator;
if (unaryOperator != null
&& unaryOperator.OperatorToken == JSToken.Void
&& unaryOperator.Operand is ConstantWrapper)
{
unaryOperator = conditional.TrueExpression as UnaryOperator;
if (unaryOperator != null && unaryOperator.OperatorToken == JSToken.Void)
{
if (isFunctionLevel)
{
// transform: ...;return cond?void 0:void 0} to ...;cond}
// function level ends in an implicit "return void 0"
node.ReplaceChild(lastReturn, conditional.Condition);
}
else
{
// transform: ...;return cond?void 0:void 0} to ...;cond;return}
// non-function level doesn't end in an implicit return,
// so we need to break them out into two statements
node.ReplaceChild(lastReturn, conditional.Condition);
node.Append(new ReturnNode(null, m_parser));
}
}
else if (isFunctionLevel)
{
// transform: ...;return cond?expr:void 0} to ...;if(cond)return expr}
// (only works at the function-level because of the implicit return statement)
var ifNode = new IfNode(lastReturn.Context, m_parser)
{
Condition = conditional.Condition,
TrueBlock = AstNode.ForceToBlock(new ReturnNode(null, m_parser)
{
Operand = conditional.TrueExpression
})
};
node.ReplaceChild(lastReturn, ifNode);
}
}
else if (isFunctionLevel)
{
unaryOperator = conditional.TrueExpression as UnaryOperator;
if (unaryOperator != null
&& unaryOperator.OperatorToken == JSToken.Void
&& unaryOperator.Operand is ConstantWrapper)
{
// transform: ...;return cond?void 0;expr} to ...;if(!cond)return expr}
// (only works at the function level because of the implicit return)
// get the logical-not of the conditional
var logicalNot = new LogicalNot(conditional.Condition, m_parser);
logicalNot.Apply();
// create a new if-node based on the condition, with the branches swapped
// (true-expression goes to false-branch, false-expression goes to true-branch
var ifNode = new IfNode(lastReturn.Context, m_parser)
{
Condition = conditional.Condition,
TrueBlock = AstNode.ForceToBlock(new ReturnNode(null, m_parser)
{
Operand = conditional.FalseExpression
})
};
node.ReplaceChild(lastReturn, ifNode);
}
}
}
}
if (m_parser.Settings.IsModificationAllowed(TreeModifications.CombineEquivalentIfReturns))
{
// walk backwards looking for if(cond1)return expr1;if(cond2)return expr2;
// (backwards, because we'll be combining those into one statement, reducing the number of statements.
// don't go all the way to zero, because each loop will compare the statement to the PREVIOUS
// statement, and the first statement (index==0) has no previous statement.
for (var ndx = node.Count - 1; ndx > 0; --ndx)
{
// see if the current statement is an if-statement with no else block, and a true
// block that contains a single return-statement WITH an expression.
AstNode currentExpr = null;
AstNode condition2;
if (IsIfReturnExpr(node[ndx], out condition2, ref currentExpr) != null)
{
// see if the previous statement is also the same pattern, but with
// the equivalent expression as its return operand
AstNode condition1;
var matchedExpression = currentExpr;
var ifNode = IsIfReturnExpr(node[ndx - 1], out condition1, ref matchedExpression);
if (ifNode != null)
{
// it is a match!
// let's combine them -- we'll add the current condition to the
// previous condition with a logical-or and delete the current statement.
// transform: if(cond1)return expr;if(cond2)return expr; to if(cond1||cond2)return expr;
ifNode.Condition = new BinaryOperator(null, m_parser)
{
Operand1 = condition1,
Operand2 = condition2,
OperatorToken = JSToken.LogicalOr,
TerminatingContext = ifNode.TerminatingContext ?? node.TerminatingContext
};
DetachReferences.Apply(currentExpr);
node.RemoveAt(ndx);
}
}
}
}
if (isFunctionLevel
&& m_parser.Settings.IsModificationAllowed(TreeModifications.InvertIfReturn))
{
// walk backwards looking for if (cond) return; whenever we encounter that statement,
// we can change it to if (!cond) and put all subsequent statements in the block inside the
// if's true-block.
for (var ndx = node.Count - 1; ndx >= 0; --ndx)
{
var ifNode = node[ndx] as IfNode;
if (ifNode != null
&& ifNode.FalseBlock == null
&& ifNode.TrueBlock != null
&& ifNode.TrueBlock.Count == 1)
{
var returnNode = ifNode.TrueBlock[0] as ReturnNode;
if (returnNode != null && returnNode.Operand == null)
{
// we have if(cond)return;
// logical-not the condition, remove the return statement,
// and move all subsequent sibling statements inside the if-statement.
LogicalNot.Apply(ifNode.Condition, m_parser);
ifNode.TrueBlock.Clear();
var ndxMove = ndx + 1;
if (node.Count == ndxMove + 1)
{
// there's only one statement after our if-node.
// see if it's ALSO an if-node with no else block.
var secondIfNode = node[ndxMove] as IfNode;
if (secondIfNode != null && (secondIfNode.FalseBlock == null || secondIfNode.FalseBlock.Count == 0))
{
// it is!
// transform: if(cond1)return;if(cond2){...} => if(!cond1&&cond2){...}
// (the cond1 is already inverted at this point)
// combine cond2 with cond1 via a logical-and,
// move all secondIf statements inside the if-node,
// remove the secondIf node.
node.RemoveAt(ndxMove);
ifNode.Condition = new BinaryOperator(null, m_parser)
{
Operand1 = ifNode.Condition,
Operand2 = secondIfNode.Condition,
OperatorToken = JSToken.LogicalAnd
};
ifNode.TrueBlock = secondIfNode.TrueBlock;
}
else if (node[ndxMove].IsExpression
&& m_parser.Settings.IsModificationAllowed(TreeModifications.IfConditionCallToConditionAndCall))
{
// now we have if(cond)expr; optimize that!
var expression = node[ndxMove];
node.RemoveAt(ndxMove);
IfConditionExpressionToExpression(ifNode, expression);
}
}
// just move all the following statements inside the if-statement
while (node.Count > ndxMove)
{
var movedNode = node[ndxMove];
node.RemoveAt(ndxMove);
ifNode.TrueBlock.Append(movedNode);
}
}
}
}
}
else
{
var isIteratorBlock = node.Parent is ForNode
|| node.Parent is ForIn
|| node.Parent is WhileNode
|| node.Parent is DoWhile;
if (isIteratorBlock
&& m_parser.Settings.IsModificationAllowed(TreeModifications.InvertIfContinue))
{
// walk backwards looking for if (cond) continue; whenever we encounter that statement,
// we can change it to if (!cond) and put all subsequent statements in the block inside the
// if's true-block.
for (var ndx = node.Count - 1; ndx >= 0; --ndx)
{
var ifNode = node[ndx] as IfNode;
if (ifNode != null
&& ifNode.FalseBlock == null
&& ifNode.TrueBlock != null
&& ifNode.TrueBlock.Count == 1)
{
var continueNode = ifNode.TrueBlock[0] as ContinueNode;
// if there's no label, then we're good. Otherwise we can only make this optimization
// if the label refers to the parent iterator node.
if (continueNode != null
&& (string.IsNullOrEmpty(continueNode.Label) || (LabelMatchesParent(continueNode.Label, node.Parent))))
{
// if this is the last statement, then we don't really need the if at all
// and can just replace it with its condition
if (ndx < node.Count - 1)
{
// we have if(cond)continue;st1;...stn;
// logical-not the condition, remove the continue statement,
// and move all subsequent sibling statements inside the if-statement.
LogicalNot.Apply(ifNode.Condition, m_parser);
ifNode.TrueBlock.Clear();
// TODO: if we removed a labeled continue, do we need to fix up some label references?
var ndxMove = ndx + 1;
if (node.Count == ndxMove + 1)
{
// there's only one statement after our if-node.
// see if it's ALSO an if-node with no else block.
var secondIfNode = node[ndxMove] as IfNode;
if (secondIfNode != null && (secondIfNode.FalseBlock == null || secondIfNode.FalseBlock.Count == 0))
{
// it is!
// transform: if(cond1)continue;if(cond2){...} => if(!cond1&&cond2){...}
// (the cond1 is already inverted at this point)
// combine cond2 with cond1 via a logical-and,
// move all secondIf statements inside the if-node,
// remove the secondIf node.
ifNode.Condition = new BinaryOperator(null, m_parser)
{
Operand1 = ifNode.Condition,
Operand2 = secondIfNode.Condition,
OperatorToken = JSToken.LogicalAnd
};
ifNode.TrueBlock = secondIfNode.TrueBlock;
node.RemoveAt(ndxMove);
}
else if (node[ndxMove].IsExpression
&& m_parser.Settings.IsModificationAllowed(TreeModifications.IfConditionCallToConditionAndCall))
{
// now we have if(cond)expr; optimize that!
var expression = node[ndxMove];
node.RemoveAt(ndxMove);
IfConditionExpressionToExpression(ifNode, expression);
}
}
// just move all the following statements inside the if-statement
while (node.Count > ndxMove)
{
var movedNode = node[ndxMove];
node.RemoveAt(ndxMove);
ifNode.TrueBlock.Append(movedNode);
}
}
else
{
// we have if(cond)continue} -- nothing after the if.
// the loop is going to continue anyway, so replace the if-statement
// with the condition and be done
if (ifNode.Condition.IsConstant)
{
// consition is constant -- get rid of the if-statement altogether
node.RemoveAt(ndx);
}
else
{
// condition isn't constant
node[ndx] = ifNode.Condition;
}
}
}
}
}
}
}
}
}
public void Visit(Block node)
{
// not applicable; terminate
}
private static void CombineWithPreviousVar(Block node, int ndx, Var previousVar)
{
var binaryOp = node[ndx] as BinaryOperator;
Lookup lookup;
if (binaryOp != null
&& binaryOp.IsAssign
&& (lookup = binaryOp.Operand1 as Lookup) != null
&& lookup.VariableField != null
&& !ContainsReference(binaryOp.Operand2, lookup.VariableField)
&& previousVar[previousVar.Count - 1].VariableField == lookup.VariableField)
{
var varDecl = previousVar[previousVar.Count - 1];
if (varDecl.Initializer != null)
{
if (binaryOp.OperatorToken == JSToken.Assign)
{
// we have var name=expr1;name=expr2. If expr1 is a constant, we will
// get rid of it entirely and replace it with expr2. Otherwise we don't
// know about any side-effects, so just leave it be.
if (varDecl.Initializer.IsConstant)
{
// transform: var name=const;name=expr ==> var name=expr
varDecl.Initializer = binaryOp.Operand2;
// getting rid of the lookup, so clean up its references
lookup.VariableField.IfNotNull(v => v.References.Remove(lookup));
node[ndx] = null;
}
}
else
{
// we have var name=expr1;name[OP]=expr2.
// transform: var name=expr1;name[OP]=expr2 ==> var name=expr1[OP]expr2
// getting rid of the lookup, so clean up its references
lookup.VariableField.IfNotNull(v => v.References.Remove(lookup));
// reuse the binary op by stripping the assignment to just the operator,
// clobbering the lookup on operand1 with the vardecl assignment,
// and expanding the context to include the initializer.
binaryOp.OperatorToken = JSScanner.StripAssignment(binaryOp.OperatorToken);
binaryOp.Operand1 = varDecl.Initializer;
binaryOp.UpdateWith(binaryOp.Operand1.Context);
// set the adjusted binary op to the vardecl initializer and remove the
// current statement (that points to the binary op)
varDecl.Initializer = binaryOp;
node[ndx] = null;
}
}
else if (binaryOp.OperatorToken == JSToken.Assign)
{
// transform: var name;name=expr ==> var name=expr
lookup.VariableField.IfNotNull(v => v.References.Remove(lookup));
varDecl.Initializer = binaryOp.Operand2;
node[ndx] = null;
}
else
{
// we have var name;name[OP]=expr.
// leave it alone???? we could make var name=undefined[OP]expr1, if we have a good undefined value.
}
}
}
private static AstNode FindLastStatement(Block node)
{
// start with the last statement in the block and back up over any function declarations
// or important comments until we get the last statement
var lastStatementIndex = node.Count - 1;
while (lastStatementIndex >= 0
&& (node[lastStatementIndex] is FunctionObject || node[lastStatementIndex] is ImportantComment))
{
--lastStatementIndex;
}
return lastStatementIndex >= 0 ? node[lastStatementIndex] : null;
}
private void CombineForNodeWithExpression(Block node, int ndx, ForNode forNode)
{
// if we aren't allowing in-operators to be moved into for-statements, then
// first check to see if that previous expression statement is free of in-operators
// before trying to move it.
if (m_parser.Settings.IsModificationAllowed(TreeModifications.MoveInExpressionsIntoForStatement)
|| !node[ndx - 1].ContainsInOperator)
{
if (forNode.Initializer == null)
{
// transform: expr1;for(;...) to for(expr1;...)
// simply move the previous expression to the for-statement's initializer
forNode.Initializer = node[ndx - 1];
node[ndx - 1] = null;
}
else if (forNode.Initializer.IsExpression)
{
// transform: expr1;for(expr2;...) to for(expr1,expr2;...)
var binOp = CommaOperator.CombineWithComma(null, m_parser, node[ndx - 1], forNode.Initializer);
// replace the initializer with the new binary operator and remove the previous node
forNode.Initializer = binOp;
node[ndx - 1] = null;
}
}
}
private static void StripDebugStatements(Block node)
{
// walk the list backwards
for (int ndx = node.Count - 1; ndx >= 0; --ndx)
{
// if this item pops positive...
if (node[ndx].IsDebuggerStatement)
{
// just remove it
DetachReferences.Apply(node[ndx]);
node.RemoveAt(ndx);
}
}
}
private void CombineReturnWithExpression(Block node, int ndx, ReturnNode returnNode)
{
// see if the return node has an expression operand
if (returnNode.Operand != null && returnNode.Operand.IsExpression)
{
// check for lookup[ASSIGN]expr2;return expr1.
var beforeExpr = node[ndx - 1] as BinaryOperator;
Lookup lookup;
if (beforeExpr != null
&& beforeExpr.IsAssign
&& (lookup = beforeExpr.Operand1 as Lookup) != null)
{
if (returnNode.Operand.IsEquivalentTo(lookup))
{
// we have lookup[ASSIGN]expr2;return lookup.
// if lookup is a local variable in the current scope, we can replace with return expr2;
// if lookup is an outer reference, we can replace with return lookup[ASSIGN]expr2
if (beforeExpr.OperatorToken == JSToken.Assign)
{
// check to see if lookup is in the current scope from which we are returning
if (lookup.VariableField == null
|| lookup.VariableField.OuterField != null
|| lookup.VariableField.IsReferencedInnerScope)
{
// transform: lookup[ASSIGN]expr2;return lookup => return lookup[ASSIGN]expr2
// lookup points to outer field (or we don't know)
// replace the operand on the return node with the previous expression and
// delete the previous node.
// first be sure to remove the lookup in the return operand from the references
// to field.
DetachReferences.Apply(returnNode.Operand);
returnNode.Operand = beforeExpr;
node[ndx - 1] = null;
}
else
{
// transform: lookup[ASSIGN]expr2;return lookup => return expr2
// lookup is a variable local to the current scope, so when we return, the
// variable won't exists anymore anyway.
// replace the operand on the return node oprand with the right-hand operand of the
// previous expression and delete the previous node.
// we're eliminating the two lookups altogether, so remove them both from the
// field's reference table.
var varField = lookup.VariableField;
DetachReferences.Apply(lookup, returnNode.Operand);
returnNode.Operand = beforeExpr.Operand2;
node[ndx - 1] = null;
// now that we've eliminated the two lookups, see if the local variable isn't
// referenced anymore. If it isn't, we might be able to remove the variable, too.
// (need to pick up those changes to keep track of a field's declarations, though)
if (varField.RefCount == 0)
{
// it's not. if there's only one declaration and it either has no initializer or
// is initialized to a constant, get rid of it.
var nameDecl = varField.OnlyDeclaration;
if (nameDecl != null)
{
// we only had one declaration.
if (nameDecl.Initializer == null || nameDecl.Initializer.IsConstant)
{
// and it either had no initializer or it was initialized to a constant.
// but it has no references, so let's whack it. Actually, only if it was
// a var-decl (leave parameter and function decls alone).
var varDecl = nameDecl as VariableDeclaration;
if (varDecl != null)
{
// save the declaration parent (var, const, or let) and remove the
// child vardecl from its list
var declStatement = varDecl.Parent as Declaration;
declStatement.Remove(varDecl);
varField.WasRemoved = true;
// if the parent statement is now empty, remove it, too. this will
// move everything up one index, but that'll just mean an extra loop.
if (declStatement.Count == 0)
{
declStatement.Parent.ReplaceChild(declStatement, null);
}
}
}
}
}
}
}
else
{
// it's an assignment, but it's not =. That means it's one of the OP= operators.
// we can't remove the field altogether. But we can move the assignment into the
// return statement and get rid of the lone lookup.
// transform: lookup OP= expr;return lookup => return lookup OP= expr;
if (lookup.VariableField != null)
{
// we're getting rid of the lookup, so remove it from the field's list of references
DetachReferences.Apply(returnNode.Operand);
}
// remove the expression from the block and put it in the operand of
// the return statement.
node.RemoveAt(ndx - 1);
returnNode.Operand = beforeExpr;
// is this field scoped only to this function?
if (lookup.VariableField != null
&& lookup.VariableField.OuterField == null
&& !lookup.VariableField.IsReferencedInnerScope)
{
// in fact, the lookup is in the current scope, so assigning to it is a waste
// because we're going to return (this is a return statement, after all).
// we can get rid of the assignment part and just keep the operator:
// transform: lookup OP= expr;return lookup => return lookup OP expr;
beforeExpr.OperatorToken = JSScanner.StripAssignment(beforeExpr.OperatorToken);
}
}
}
else
{
// transform: expr1;return expr2 to return expr1,expr2
var binOp = CommaOperator.CombineWithComma(null, m_parser, node[ndx - 1], returnNode.Operand);
// replace the operand on the return node with the new expression and
// delete the previous node
returnNode.Operand = binOp;
node[ndx - 1] = null;
}
}
else
{
// transform: expr1;return expr2 to return expr1,expr2
var binOp = CommaOperator.CombineWithComma(null, m_parser, node[ndx - 1], returnNode.Operand);
// replace the operand on the return node with the new expression and
// delete the previous node
returnNode.Operand = binOp;
node[ndx - 1] = null;
}
}
}
//---------------------------------------------------------------------------------------
// ParseTryStatement
//
// TryStatement :
// 'try' Block Catch Finally
//
// Catch :
// <empty> | 'catch' '(' Identifier ')' Block
//
// Finally :
// <empty> |
// 'finally' Block
//---------------------------------------------------------------------------------------
private AstNode ParseTryStatement()
{
Context tryCtx = m_currentToken.Clone();
Context catchContext = null;
Context finallyContext = null;
Context tryEndContext = null;
Block body = null;
Context idContext = null;
Block handler = null;
Block finally_block = null;
RecoveryTokenException excInFinally = null;
m_blockType.Add(BlockType.Block);
try
{
bool catchOrFinally = false;
GetNextToken();
if (JSToken.LeftCurly != m_currentToken.Token)
{
ReportError(JSError.NoLeftCurly);
}
m_noSkipTokenSet.Add(NoSkipTokenSet.s_NoTrySkipTokenSet);
try
{
body = ParseBlock(out tryEndContext);
}
catch (RecoveryTokenException exc)
{
if (IndexOfToken(NoSkipTokenSet.s_NoTrySkipTokenSet, exc) == -1)
{
// do nothing and just return the containing block, if any
throw;
}
else
{
body = exc._partiallyComputedNode as Block;
if (body == null)
{
body = new Block(exc._partiallyComputedNode.Context, this);
body.Append(exc._partiallyComputedNode);
}
}
}
finally
{
m_noSkipTokenSet.Remove(NoSkipTokenSet.s_NoTrySkipTokenSet);
}
if (JSToken.Catch == m_currentToken.Token)
{
m_noSkipTokenSet.Add(NoSkipTokenSet.s_NoTrySkipTokenSet);
try
{
catchOrFinally = true;
catchContext = m_currentToken.Clone();
GetNextToken();
if (JSToken.LeftParenthesis != m_currentToken.Token)
{
ReportError(JSError.NoLeftParenthesis);
}
GetNextToken();
if (JSToken.Identifier != m_currentToken.Token)
{
string identifier = JSKeyword.CanBeIdentifier(m_currentToken.Token);
if (null != identifier)
{
idContext = m_currentToken.Clone();
}
else
{
ReportError(JSError.NoIdentifier);
}
}
else
{
idContext = m_currentToken.Clone();
}
GetNextToken();
m_noSkipTokenSet.Add(NoSkipTokenSet.s_BlockConditionNoSkipTokenSet);
try
{
if (JSToken.RightParenthesis != m_currentToken.Token)
{
ReportError(JSError.NoRightParenthesis);
}
GetNextToken();
}
catch (RecoveryTokenException exc)
{
if (IndexOfToken(NoSkipTokenSet.s_BlockConditionNoSkipTokenSet, exc) == -1)
{
exc._partiallyComputedNode = null;
// rethrow
throw;
}
else
{
if (m_currentToken.Token == JSToken.RightParenthesis)
{
GetNextToken();
}
}
}
finally
{
m_noSkipTokenSet.Remove(NoSkipTokenSet.s_BlockConditionNoSkipTokenSet);
}
if (JSToken.LeftCurly != m_currentToken.Token)
{
ReportError(JSError.NoLeftCurly);
}
// parse the block
handler = ParseBlock();
tryCtx.UpdateWith(handler.Context);
}
catch (RecoveryTokenException exc)
{
if (exc._partiallyComputedNode == null)
{
handler = new Block(CurrentPositionContext(), this);
}
else
{
handler = exc._partiallyComputedNode as Block;
if (handler == null)
{
handler = new Block(exc._partiallyComputedNode.Context, this);
handler.Append(exc._partiallyComputedNode);
}
}
if (IndexOfToken(NoSkipTokenSet.s_NoTrySkipTokenSet, exc) == -1)
{
throw;
}
}
finally
{
m_noSkipTokenSet.Remove(NoSkipTokenSet.s_NoTrySkipTokenSet);
}
}
try
{
if (JSToken.Finally == m_currentToken.Token)
{
finallyContext = m_currentToken.Clone();
GetNextToken();
m_blockType.Add(BlockType.Finally);
try
{
finally_block = ParseBlock();
catchOrFinally = true;
}
finally
{
m_blockType.RemoveAt(m_blockType.Count - 1);
}
tryCtx.UpdateWith(finally_block.Context);
}
}
catch (RecoveryTokenException exc)
{
excInFinally = exc; // thrown later so we can execute code below
}
if (!catchOrFinally)
{
ReportError(JSError.NoCatch, true);
finally_block = new Block(CurrentPositionContext(), this); // make a dummy empty block
}
}
finally
{
m_blockType.RemoveAt(m_blockType.Count - 1);
}
ParameterDeclaration catchParameter = null;
if (idContext != null)
{
catchParameter = new ParameterDeclaration(idContext, this)
{
Name = idContext.Code
};
}
if (excInFinally != null)
{
excInFinally._partiallyComputedNode = new TryNode(tryCtx, this)
{
TryBlock = body,
CatchContext = catchContext,
CatchParameter = catchParameter,
CatchBlock = handler,
FinallyContext = finallyContext,
FinallyBlock = finally_block
};
throw excInFinally;
}
return new TryNode(tryCtx, this)
{
TryBlock = body,
CatchContext = catchContext,
CatchParameter = catchParameter,
CatchBlock = handler,
FinallyContext = finallyContext,
FinallyBlock = finally_block
};
}
Block ParseBlock(out Context closingBraceContext)
{
closingBraceContext = null;
m_blockType.Add(BlockType.Block);
Block codeBlock = new Block(m_currentToken.Clone(), this);
codeBlock.BraceOnNewLine = m_foundEndOfLine;
GetNextToken();
m_noSkipTokenSet.Add(NoSkipTokenSet.s_StartStatementNoSkipTokenSet);
m_noSkipTokenSet.Add(NoSkipTokenSet.s_BlockNoSkipTokenSet);
try
{
try
{
while (JSToken.RightCurly != m_currentToken.Token)
{
try
{
// pass false because we really only want Statements, and FunctionDeclarations
// are technically not statements. We'll still handle them, but we'll issue a warning.
codeBlock.Append(ParseStatement(false));
}
catch (RecoveryTokenException exc)
{
if (exc._partiallyComputedNode != null)
codeBlock.Append(exc._partiallyComputedNode);
if (IndexOfToken(NoSkipTokenSet.s_StartStatementNoSkipTokenSet, exc) == -1)
throw;
}
}
// make sure any important comments before the closing brace are kept
if (m_importantComments.Count > 0
&& m_settings.PreserveImportantComments
&& m_settings.IsModificationAllowed(TreeModifications.PreserveImportantComments))
{
// we have important comments before the EOF. Add the comment(s) to the program.
foreach (var importantComment in m_importantComments)
{
codeBlock.Append(new ImportantComment(importantComment, this));
}
m_importantComments.Clear();
}
}
catch (RecoveryTokenException exc)
{
if (IndexOfToken(NoSkipTokenSet.s_BlockNoSkipTokenSet, exc) == -1)
{
exc._partiallyComputedNode = codeBlock;
throw;
}
}
}
finally
{
m_noSkipTokenSet.Remove(NoSkipTokenSet.s_BlockNoSkipTokenSet);
m_noSkipTokenSet.Remove(NoSkipTokenSet.s_StartStatementNoSkipTokenSet);
m_blockType.RemoveAt(m_blockType.Count - 1);
}
closingBraceContext = m_currentToken.Clone();
// update the block context
codeBlock.Context.UpdateWith(m_currentToken);
GetNextToken();
return codeBlock;
}
private FunctionObject ParseFunction(FunctionType functionType, Context fncCtx)
{
Lookup name = null;
AstNodeList formalParameters = null;
Block body = null;
bool inExpression = (functionType == FunctionType.Expression);
Context paramsContext = null;
GetNextToken();
// get the function name or make an anonymous function if in expression "position"
if (JSToken.Identifier == m_currentToken.Token)
{
name = new Lookup(m_currentToken.Clone(), this)
{
Name = m_scanner.Identifier
};
GetNextToken();
}
else
{
string identifier = JSKeyword.CanBeIdentifier(m_currentToken.Token);
if (null != identifier)
{
name = new Lookup(m_currentToken.Clone(), this)
{
Name = identifier
};
GetNextToken();
}
else
{
if (!inExpression)
{
// if this isn't a function expression, then we need to throw an error because
// function DECLARATIONS always need a valid identifier name
ReportError(JSError.NoIdentifier, m_currentToken.Clone(), true);
// BUT if the current token is a left paren, we don't want to use it as the name.
// (fix for issue #14152)
if (m_currentToken.Token != JSToken.LeftParenthesis
&& m_currentToken.Token != JSToken.LeftCurly)
{
identifier = m_currentToken.Code;
name = new Lookup(CurrentPositionContext(), this)
{
Name = identifier
};
GetNextToken();
}
}
}
}
// make a new state and save the old one
List<BlockType> blockType = m_blockType;
m_blockType = new List<BlockType>(16);
Dictionary<string, LabelInfo> labelTable = m_labelTable;
m_labelTable = new Dictionary<string, LabelInfo>();
try
{
// get the formal parameters
if (JSToken.LeftParenthesis != m_currentToken.Token)
{
// we expect a left paren at this point for standard cross-browser support.
// BUT -- some versions of IE allow an object property expression to be a function name, like window.onclick.
// we still want to throw the error, because it syntax errors on most browsers, but we still want to
// be able to parse it and return the intended results.
// Skip to the open paren and use whatever is in-between as the function name. Doesn't matter that it's
// an invalid identifier; it won't be accessible as a valid field anyway.
bool expandedIndentifier = false;
while (m_currentToken.Token != JSToken.LeftParenthesis
&& m_currentToken.Token != JSToken.LeftCurly
&& m_currentToken.Token != JSToken.Semicolon
&& m_currentToken.Token != JSToken.EndOfFile)
{
name.Context.UpdateWith(m_currentToken);
GetNextToken();
expandedIndentifier = true;
}
// if we actually expanded the identifier context, then we want to report that
// the function name needs to be an identifier. Otherwise we didn't expand the
// name, so just report that we expected an open paren at this point.
if (expandedIndentifier)
{
name.Name = name.Context.Code;
name.Context.HandleError(JSError.FunctionNameMustBeIdentifier, false);
}
else
{
ReportError(JSError.NoLeftParenthesis, true);
}
}
if (m_currentToken.Token == JSToken.LeftParenthesis)
{
// create the parameter list
formalParameters = new AstNodeList(m_currentToken.Clone(), this);
paramsContext = m_currentToken.Clone();
// skip the open paren
GetNextToken();
// create the list of arguments and update the context
while (JSToken.RightParenthesis != m_currentToken.Token)
{
String id = null;
m_noSkipTokenSet.Add(NoSkipTokenSet.s_FunctionDeclNoSkipTokenSet);
try
{
ParameterDeclaration paramDecl = null;
if (JSToken.Identifier != m_currentToken.Token && (id = JSKeyword.CanBeIdentifier(m_currentToken.Token)) == null)
{
if (JSToken.LeftCurly == m_currentToken.Token)
{
ReportError(JSError.NoRightParenthesis);
break;
}
else if (JSToken.Comma == m_currentToken.Token)
{
// We're missing an argument (or previous argument was malformed and
// we skipped to the comma.) Keep trying to parse the argument list --
// we will skip the comma below.
ReportError(JSError.SyntaxError, true);
}
else
{
ReportError(JSError.SyntaxError, true);
SkipTokensAndThrow();
}
}
else
{
if (null == id)
{
id = m_scanner.Identifier;
}
paramDecl = new ParameterDeclaration(m_currentToken.Clone(), this)
{
Name = id,
Position = formalParameters.Count
};
formalParameters.Append(paramDecl);
GetNextToken();
}
// got an arg, it should be either a ',' or ')'
if (JSToken.RightParenthesis == m_currentToken.Token)
{
break;
}
else if (JSToken.Comma == m_currentToken.Token)
{
// append the comma context as the terminator for the parameter
paramDecl.IfNotNull(p => p.TerminatingContext = m_currentToken.Clone());
}
else
{
// deal with error in some "intelligent" way
if (JSToken.LeftCurly == m_currentToken.Token)
{
ReportError(JSError.NoRightParenthesis);
break;
}
else
{
if (JSToken.Identifier == m_currentToken.Token)
{
// it's possible that the guy was writing the type in C/C++ style (i.e. int x)
ReportError(JSError.NoCommaOrTypeDefinitionError);
}
else
ReportError(JSError.NoComma);
}
}
GetNextToken();
}
catch (RecoveryTokenException exc)
{
if (IndexOfToken(NoSkipTokenSet.s_FunctionDeclNoSkipTokenSet, exc) == -1)
throw;
}
finally
{
m_noSkipTokenSet.Remove(NoSkipTokenSet.s_FunctionDeclNoSkipTokenSet);
}
}
fncCtx.UpdateWith(m_currentToken);
GetNextToken();
}
// read the function body of non-abstract functions.
if (JSToken.LeftCurly != m_currentToken.Token)
ReportError(JSError.NoLeftCurly, true);
m_blockType.Add(BlockType.Block);
m_noSkipTokenSet.Add(NoSkipTokenSet.s_BlockNoSkipTokenSet);
m_noSkipTokenSet.Add(NoSkipTokenSet.s_StartStatementNoSkipTokenSet);
try
{
// parse the block locally to get the exact end of function
body = new Block(m_currentToken.Clone(), this);
body.BraceOnNewLine = m_foundEndOfLine;
GetNextToken();
var possibleDirectivePrologue = true;
while (JSToken.RightCurly != m_currentToken.Token)
{
try
{
// function body's are SourceElements (Statements + FunctionDeclarations)
var statement = ParseStatement(true);
if (possibleDirectivePrologue)
{
var constantWrapper = statement as ConstantWrapper;
if (constantWrapper != null && constantWrapper.PrimitiveType == PrimitiveType.String)
{
// if it's already a directive prologues, we're good to go
if (!(constantWrapper is DirectivePrologue))
{
// make the statement a directive prologue instead of a constant wrapper
statement = new DirectivePrologue(constantWrapper.Value.ToString(), constantWrapper.Context, constantWrapper.Parser)
{
MayHaveIssues = constantWrapper.MayHaveIssues
};
}
}
else if (!m_newModule)
{
// no longer considering constant wrappers
possibleDirectivePrologue = false;
}
}
else if (m_newModule)
{
// we scanned into a new module -- we might find directive prologues again
possibleDirectivePrologue = true;
}
// add it to the body
body.Append(statement);
}
catch (RecoveryTokenException exc)
{
if (exc._partiallyComputedNode != null)
{
body.Append(exc._partiallyComputedNode);
}
if (IndexOfToken(NoSkipTokenSet.s_StartStatementNoSkipTokenSet, exc) == -1)
throw;
}
}
// make sure any important comments before the closing brace are kept
if (m_importantComments.Count > 0
&& m_settings.PreserveImportantComments
&& m_settings.IsModificationAllowed(TreeModifications.PreserveImportantComments))
{
// we have important comments before the EOF. Add the comment(s) to the program.
foreach (var importantComment in m_importantComments)
{
body.Append(new ImportantComment(importantComment, this));
}
m_importantComments.Clear();
}
body.Context.UpdateWith(m_currentToken);
fncCtx.UpdateWith(m_currentToken);
}
catch (EndOfFileException)
{
// if we get an EOF here, we never had a chance to find the closing curly-brace
fncCtx.HandleError(JSError.UnclosedFunction, true);
}
catch (RecoveryTokenException exc)
{
if (IndexOfToken(NoSkipTokenSet.s_BlockNoSkipTokenSet, exc) == -1)
{
exc._partiallyComputedNode = new FunctionObject(fncCtx, this)
{
FunctionType = (inExpression ? FunctionType.Expression : FunctionType.Declaration),
IdContext = name.IfNotNull(n => n.Context),
Name = name.IfNotNull(n => n.Name),
ParameterDeclarations = formalParameters,
ParametersContext = paramsContext,
Body = body
};
throw;
}
}
finally
{
m_blockType.RemoveAt(m_blockType.Count - 1);
m_noSkipTokenSet.Remove(NoSkipTokenSet.s_StartStatementNoSkipTokenSet);
m_noSkipTokenSet.Remove(NoSkipTokenSet.s_BlockNoSkipTokenSet);
}
GetNextToken();
}
finally
{
// restore state
m_blockType = blockType;
m_labelTable = labelTable;
}
return new FunctionObject(fncCtx, this)
{
FunctionType = functionType,
IdContext = name.IfNotNull(n => n.Context),
Name = name.IfNotNull(n => n.Name),
ParameterDeclarations = formalParameters,
ParametersContext = paramsContext,
Body = body
};
}
//---------------------------------------------------------------------------------------
// ParseIfStatement
//
// IfStatement :
// 'if' '(' Expression ')' Statement ElseStatement
//
// ElseStatement :
// <empty> |
// 'else' Statement
//---------------------------------------------------------------------------------------
private IfNode ParseIfStatement()
{
Context ifCtx = m_currentToken.Clone();
AstNode condition = null;
AstNode trueBranch = null;
AstNode falseBranch = null;
Context elseCtx = null;
m_blockType.Add(BlockType.Block);
try
{
// parse condition
GetNextToken();
m_noSkipTokenSet.Add(NoSkipTokenSet.s_BlockConditionNoSkipTokenSet);
try
{
if (JSToken.LeftParenthesis != m_currentToken.Token)
ReportError(JSError.NoLeftParenthesis);
GetNextToken();
condition = ParseExpression();
// parse statements
if (JSToken.RightParenthesis != m_currentToken.Token)
{
ifCtx.UpdateWith(condition.Context);
ReportError(JSError.NoRightParenthesis);
}
else
ifCtx.UpdateWith(m_currentToken);
GetNextToken();
}
catch (RecoveryTokenException exc)
{
// make up an if condition
if (exc._partiallyComputedNode != null)
condition = exc._partiallyComputedNode;
else
condition = new ConstantWrapper(true, PrimitiveType.Boolean, CurrentPositionContext(), this);
if (IndexOfToken(NoSkipTokenSet.s_BlockConditionNoSkipTokenSet, exc) == -1)
{
exc._partiallyComputedNode = null; // really not much to pass up
// the if condition was so bogus we do not have a chance to make an If node, give up
throw;
}
else
{
if (exc._token == JSToken.RightParenthesis)
GetNextToken();
}
}
finally
{
m_noSkipTokenSet.Remove(NoSkipTokenSet.s_BlockConditionNoSkipTokenSet);
}
// if this is an assignment, throw a warning in case the developer
// meant to use == instead of =
// but no warning if the condition is wrapped in parens.
var binOp = condition as BinaryOperator;
if (binOp != null && binOp.OperatorToken == JSToken.Assign)
{
condition.Context.HandleError(JSError.SuspectAssignment);
}
m_noSkipTokenSet.Add(NoSkipTokenSet.s_IfBodyNoSkipTokenSet);
if (JSToken.Semicolon == m_currentToken.Token)
{
m_currentToken.HandleError(JSError.SuspectSemicolon);
}
else if (JSToken.LeftCurly != m_currentToken.Token)
{
// if the statements aren't withing curly-braces, throw a possible error
ReportError(JSError.StatementBlockExpected, CurrentPositionContext(), true);
}
try
{
// parse a Statement, not a SourceElement
trueBranch = ParseStatement(false);
}
catch (RecoveryTokenException exc)
{
// make up a block for the if part
if (exc._partiallyComputedNode != null)
trueBranch = exc._partiallyComputedNode;
else
trueBranch = new Block(CurrentPositionContext(), this);
if (IndexOfToken(NoSkipTokenSet.s_IfBodyNoSkipTokenSet, exc) == -1)
{
// we have to pass the exception to someone else, make as much as you can from the if
exc._partiallyComputedNode = new IfNode(ifCtx, this)
{
Condition = condition,
TrueBlock = AstNode.ForceToBlock(trueBranch)
};
throw;
}
}
finally
{
if (trueBranch != null)
{
ifCtx.UpdateWith(trueBranch.Context);
}
m_noSkipTokenSet.Remove(NoSkipTokenSet.s_IfBodyNoSkipTokenSet);
}
// parse else, if any
if (JSToken.Else == m_currentToken.Token)
{
elseCtx = m_currentToken.Clone();
GetNextToken();
if (JSToken.Semicolon == m_currentToken.Token)
{
m_currentToken.HandleError(JSError.SuspectSemicolon);
}
else if (JSToken.LeftCurly != m_currentToken.Token
&& JSToken.If != m_currentToken.Token)
{
// if the statements aren't withing curly-braces (or start another if-statement), throw a possible error
ReportError(JSError.StatementBlockExpected, CurrentPositionContext(), true);
}
try
{
// parse a Statement, not a SourceElement
falseBranch = ParseStatement(false);
}
catch (RecoveryTokenException exc)
{
// make up a block for the else part
if (exc._partiallyComputedNode != null)
falseBranch = exc._partiallyComputedNode;
else
falseBranch = new Block(CurrentPositionContext(), this);
exc._partiallyComputedNode = new IfNode(ifCtx, this)
{
Condition = condition,
TrueBlock = AstNode.ForceToBlock(trueBranch),
ElseContext = elseCtx,
FalseBlock = AstNode.ForceToBlock(falseBranch)
};
throw;
}
finally
{
if (falseBranch != null)
{
ifCtx.UpdateWith(falseBranch.Context);
}
}
}
}
finally
{
m_blockType.RemoveAt(m_blockType.Count - 1);
}
return new IfNode(ifCtx, this)
{
Condition = condition,
TrueBlock = AstNode.ForceToBlock(trueBranch),
ElseContext = elseCtx,
FalseBlock = AstNode.ForceToBlock(falseBranch)
};
}
//---------------------------------------------------------------------------------------
// ParseStatements
//
// statements :
// <empty> |
// statement statements
//
//---------------------------------------------------------------------------------------
private Block ParseStatements()
{
var program = new Block(CurrentPositionContext(), this);
m_blockType.Add(BlockType.Block);
m_useCurrentForNext = false;
try
{
// get the first token
GetNextToken();
// if the block doesn't have a proper file context, then let's set it from the
// first token -- that token might have had a ///#source directive!
if (string.IsNullOrEmpty(program.Context.Document.FileContext))
{
program.Context.Document.FileContext = m_currentToken.Document.FileContext;
}
m_noSkipTokenSet.Add(NoSkipTokenSet.s_StartStatementNoSkipTokenSet);
m_noSkipTokenSet.Add(NoSkipTokenSet.s_TopLevelNoSkipTokenSet);
try
{
var possibleDirectivePrologue = true;
int lastEndPosition = m_currentToken.EndPosition;
while (m_currentToken.Token != JSToken.EndOfFile)
{
AstNode ast = null;
try
{
// parse a statement -- pass true because we really want a SourceElement,
// which is a Statement OR a FunctionDeclaration. Technically, FunctionDeclarations
// are not statements!
ast = ParseStatement(true);
// if we are still possibly looking for directive prologues
if (possibleDirectivePrologue)
{
var constantWrapper = ast as ConstantWrapper;
if (constantWrapper != null && constantWrapper.PrimitiveType == PrimitiveType.String)
{
if (!(constantWrapper is DirectivePrologue))
{
// use a directive prologue node instead
ast = new DirectivePrologue(constantWrapper.Value.ToString(), ast.Context, ast.Parser)
{
MayHaveIssues = constantWrapper.MayHaveIssues
};
}
}
else if (!m_newModule)
{
// nope -- no longer finding directive prologues
possibleDirectivePrologue = false;
}
}
else if (m_newModule)
{
// we aren't looking for directive prologues anymore, but we did scan
// into a new module after that last AST, so reset the flag because that
// new module might have directive prologues for next time
possibleDirectivePrologue = true;
}
}
catch (RecoveryTokenException exc)
{
if (TokenInList(NoSkipTokenSet.s_TopLevelNoSkipTokenSet, exc)
|| TokenInList(NoSkipTokenSet.s_StartStatementNoSkipTokenSet, exc))
{
ast = exc._partiallyComputedNode;
GetNextToken();
}
else
{
m_useCurrentForNext = false;
do
{
GetNextToken();
} while (m_currentToken.Token != JSToken.EndOfFile && !TokenInList(NoSkipTokenSet.s_TopLevelNoSkipTokenSet, m_currentToken.Token)
&& !TokenInList(NoSkipTokenSet.s_StartStatementNoSkipTokenSet, m_currentToken.Token));
}
}
if (null != ast)
{
// append the token to the program
program.Append(ast);
// set the last end position to be the start of the current token.
// if we parse the next statement and the end is still the start, we know
// something is up and might get into an infinite loop.
lastEndPosition = m_currentToken.EndPosition;
}
else if (!m_scanner.IsEndOfFile && m_currentToken.StartLinePosition == lastEndPosition)
{
// didn't parse a statement, we're not at the EOF, and we didn't move
// anywhere in the input stream. If we just keep looping around, we're going
// to get into an infinite loop. Break it.
m_currentToken.HandleError(JSError.ApplicationError, true);
break;
}
}
if (m_importantComments.Count > 0
&& m_settings.PreserveImportantComments
&& m_settings.IsModificationAllowed(TreeModifications.PreserveImportantComments))
{
// we have important comments before the EOF. Add the comment(s) to the program.
foreach(var importantComment in m_importantComments)
{
program.Append(new ImportantComment(importantComment, this));
}
m_importantComments.Clear();
}
}
finally
{
m_noSkipTokenSet.Remove(NoSkipTokenSet.s_TopLevelNoSkipTokenSet);
m_noSkipTokenSet.Remove(NoSkipTokenSet.s_StartStatementNoSkipTokenSet);
}
}
catch (EndOfFileException)
{
}
catch (ScannerException se)
{
// a scanner exception implies that the end of file has been reached with an error.
// Mark the end of file as the error location
EOFError(se.Error);
}
program.UpdateWith(CurrentPositionContext());
return program;
}
private AstNode ParseForStatement()
{
m_blockType.Add(BlockType.Loop);
AstNode forNode = null;
try
{
Context forCtx = m_currentToken.Clone();
GetNextToken();
if (JSToken.LeftParenthesis != m_currentToken.Token)
{
ReportError(JSError.NoLeftParenthesis);
}
GetNextToken();
bool isForIn = false, recoveryInForIn = false;
AstNode lhs = null, initializer = null, condOrColl = null, increment = null;
Context operatorContext = null;
Context separator1Context = null;
Context separator2Context = null;
try
{
if (JSToken.Var == m_currentToken.Token
|| JSToken.Let == m_currentToken.Token
|| JSToken.Const == m_currentToken.Token)
{
isForIn = true;
Declaration declaration;
if (m_currentToken.Token == JSToken.Var)
{
declaration = new Var(m_currentToken.Clone(), this);
}
else
{
declaration = new LexicalDeclaration(m_currentToken.Clone(), this)
{
StatementToken = m_currentToken.Token
};
}
declaration.Append(ParseIdentifierInitializer(JSToken.In));
// a list of variable initializers is allowed only in a for(;;)
while (JSToken.Comma == m_currentToken.Token)
{
isForIn = false;
declaration.Append(ParseIdentifierInitializer(JSToken.In));
//initializer = new Comma(initializer.context.CombineWith(var.context), initializer, var);
}
initializer = declaration;
// if it could still be a for..in, now it's time to get the 'in'
// TODO: for ES6 might be 'of'
if (isForIn)
{
if (JSToken.In == m_currentToken.Token
|| (m_currentToken.Token == JSToken.Identifier && string.CompareOrdinal(m_currentToken.Code, "of") == 0))
{
operatorContext = m_currentToken.Clone();
GetNextToken();
condOrColl = ParseExpression();
}
else
{
isForIn = false;
}
}
}
else
{
if (JSToken.Semicolon != m_currentToken.Token)
{
bool isLHS;
initializer = ParseUnaryExpression(out isLHS, false);
if (isLHS && (JSToken.In == m_currentToken.Token
|| (m_currentToken.Token == JSToken.Identifier && string.CompareOrdinal(m_currentToken.Code, "of") == 0)))
{
isForIn = true;
operatorContext = m_currentToken.Clone();
lhs = initializer;
initializer = null;
GetNextToken();
m_noSkipTokenSet.Add(NoSkipTokenSet.s_BlockConditionNoSkipTokenSet);
try
{
condOrColl = ParseExpression();
}
catch (RecoveryTokenException exc)
{
if (IndexOfToken(NoSkipTokenSet.s_BlockConditionNoSkipTokenSet, exc) == -1)
{
exc._partiallyComputedNode = null;
throw;
}
else
{
if (exc._partiallyComputedNode == null)
condOrColl = new ConstantWrapper(true, PrimitiveType.Boolean, CurrentPositionContext(), this); // what could we put here?
else
condOrColl = exc._partiallyComputedNode;
}
if (exc._token == JSToken.RightParenthesis)
{
GetNextToken();
recoveryInForIn = true;
}
}
finally
{
m_noSkipTokenSet.Remove(NoSkipTokenSet.s_BlockConditionNoSkipTokenSet);
}
}
else
{
initializer = ParseExpression(initializer, false, isLHS, JSToken.In);
}
}
}
}
catch (RecoveryTokenException exc)
{
// error is too early abort for
exc._partiallyComputedNode = null;
throw;
}
// at this point we know whether or not is a for..in
if (isForIn)
{
if (!recoveryInForIn)
{
if (JSToken.RightParenthesis != m_currentToken.Token)
ReportError(JSError.NoRightParenthesis);
forCtx.UpdateWith(m_currentToken);
GetNextToken();
}
AstNode body = null;
// if the statements aren't withing curly-braces, throw a possible error
if (JSToken.LeftCurly != m_currentToken.Token)
{
ReportError(JSError.StatementBlockExpected, CurrentPositionContext(), true);
}
try
{
// parse a Statement, not a SourceElement
body = ParseStatement(false);
}
catch (RecoveryTokenException exc)
{
if (exc._partiallyComputedNode == null)
body = new Block(CurrentPositionContext(), this);
else
body = exc._partiallyComputedNode;
exc._partiallyComputedNode = new ForIn(forCtx, this)
{
Variable = (lhs != null ? lhs : initializer),
OperatorContext = operatorContext,
Collection = condOrColl,
Body = AstNode.ForceToBlock(body),
};
throw;
}
// for (a in b)
// lhs = a, initializer = null
// for (var a in b)
// lhs = null, initializer = var a
forNode = new ForIn(forCtx, this)
{
Variable = (lhs != null ? lhs : initializer),
OperatorContext = operatorContext,
Collection = condOrColl,
Body = AstNode.ForceToBlock(body),
};
}
else
{
m_noSkipTokenSet.Add(NoSkipTokenSet.s_BlockConditionNoSkipTokenSet);
try
{
if (JSToken.Semicolon == m_currentToken.Token)
{
separator1Context = m_currentToken.Clone();
}
else
{
ReportError(JSError.NoSemicolon);
if (JSToken.Colon == m_currentToken.Token)
{
m_noSkipTokenSet.Add(NoSkipTokenSet.s_VariableDeclNoSkipTokenSet);
try
{
SkipTokensAndThrow();
}
catch (RecoveryTokenException)
{
if (JSToken.Semicolon == m_currentToken.Token)
{
m_useCurrentForNext = false;
}
else
{
throw;
}
}
finally
{
m_noSkipTokenSet.Remove(NoSkipTokenSet.s_VariableDeclNoSkipTokenSet);
}
}
}
GetNextToken();
if (JSToken.Semicolon != m_currentToken.Token)
{
condOrColl = ParseExpression();
if (JSToken.Semicolon != m_currentToken.Token)
{
ReportError(JSError.NoSemicolon);
}
}
separator2Context = m_currentToken.Clone();
GetNextToken();
if (JSToken.RightParenthesis != m_currentToken.Token)
{
increment = ParseExpression();
}
if (JSToken.RightParenthesis != m_currentToken.Token)
{
ReportError(JSError.NoRightParenthesis);
}
forCtx.UpdateWith(m_currentToken);
GetNextToken();
}
catch (RecoveryTokenException exc)
{
if (IndexOfToken(NoSkipTokenSet.s_BlockConditionNoSkipTokenSet, exc) == -1)
{
exc._partiallyComputedNode = null;
throw;
}
else
{
// discard any partial info, just genrate empty condition and increment and keep going
exc._partiallyComputedNode = null;
if (condOrColl == null)
condOrColl = new ConstantWrapper(true, PrimitiveType.Boolean, CurrentPositionContext(), this);
}
if (exc._token == JSToken.RightParenthesis)
{
GetNextToken();
}
}
finally
{
m_noSkipTokenSet.Remove(NoSkipTokenSet.s_BlockConditionNoSkipTokenSet);
}
// if this is an assignment, throw a warning in case the developer
// meant to use == instead of =
// but no warning if the condition is wrapped in parens.
var binOp = condOrColl as BinaryOperator;
if (binOp != null && binOp.OperatorToken == JSToken.Assign)
{
condOrColl.Context.HandleError(JSError.SuspectAssignment);
}
AstNode body = null;
// if the statements aren't withing curly-braces, throw a possible error
if (JSToken.LeftCurly != m_currentToken.Token)
{
ReportError(JSError.StatementBlockExpected, CurrentPositionContext(), true);
}
try
{
// parse a Statement, not a SourceElement
body = ParseStatement(false);
}
catch (RecoveryTokenException exc)
{
if (exc._partiallyComputedNode == null)
body = new Block(CurrentPositionContext(), this);
else
body = exc._partiallyComputedNode;
exc._partiallyComputedNode = new ForNode(forCtx, this)
{
Initializer = initializer,
Separator1Context = separator1Context,
Condition = condOrColl,
Separator2Context = separator2Context,
Incrementer = increment,
Body = AstNode.ForceToBlock(body)
};
throw;
}
forNode = new ForNode(forCtx, this)
{
Initializer = initializer,
Separator1Context = separator1Context,
Condition = condOrColl,
Separator2Context = separator2Context,
Incrementer = increment,
Body = AstNode.ForceToBlock(body)
};
}
}
finally
{
m_blockType.RemoveAt(m_blockType.Count - 1);
}
return forNode;
}
public void Visit(Block node)
{
if (node != null)
{
node.Index = NextOrderIndex;
if (node.BlockScope == null
&& node.Parent != null
&& !(node.Parent is SwitchCase)
&& !(node.Parent is FunctionObject)
&& !(node.Parent is ConditionalCompilationComment))
{
node.BlockScope = new BlockScope(CurrentLexicalScope, node.Context, m_settings)
{
IsInWithScope = m_withDepth > 0
};
}
if (node.BlockScope != null)
{
m_lexicalStack.Push(node.BlockScope);
}
try
{
// recurse the block statements
for (var ndx = 0; ndx < node.Count; ++ndx)
{
var statement = node[ndx];
if (statement != null)
{
statement.Accept(this);
}
}
}
finally
{
// be sure to reset the unreachable flag when we exit this block
m_isUnreachable = false;
if (node.BlockScope != null)
{
Debug.Assert(CurrentLexicalScope == node.BlockScope);
m_lexicalStack.Pop();
}
}
// now, if the block has no lex-decls, we really don't need a separate scope.
if (node.BlockScope != null
&& !(node.BlockScope is WithScope)
&& !(node.BlockScope is CatchScope)
&& node.BlockScope.LexicallyDeclaredNames.Count == 0)
{
CollapseBlockScope(node.BlockScope);
node.BlockScope = null;
}
}
}
//---------------------------------------------------------------------------------------
// ParseDoStatement
//
// DoStatement:
// 'do' Statement 'while' '(' Expression ')'
//---------------------------------------------------------------------------------------
private DoWhile ParseDoStatement()
{
var doCtx = m_currentToken.Clone();
Context whileContext = null;
Context terminatorContext = null;
AstNode body = null;
AstNode condition = null;
m_blockType.Add(BlockType.Loop);
try
{
GetNextToken();
m_noSkipTokenSet.Add(NoSkipTokenSet.s_DoWhileBodyNoSkipTokenSet);
// if the statements aren't withing curly-braces, throw a possible error
if (JSToken.LeftCurly != m_currentToken.Token)
{
ReportError(JSError.StatementBlockExpected, CurrentPositionContext(), true);
}
try
{
// parse a Statement, not a SourceElement
body = ParseStatement(false);
}
catch (RecoveryTokenException exc)
{
// make up a block for the do while
if (exc._partiallyComputedNode != null)
body = exc._partiallyComputedNode;
else
body = new Block(CurrentPositionContext(), this);
if (IndexOfToken(NoSkipTokenSet.s_DoWhileBodyNoSkipTokenSet, exc) == -1)
{
// we have to pass the exception to someone else, make as much as you can from the 'do while'
exc._partiallyComputedNode = new DoWhile(doCtx.UpdateWith(CurrentPositionContext()), this)
{
Body = AstNode.ForceToBlock(body),
Condition = new ConstantWrapper(false, PrimitiveType.Boolean, CurrentPositionContext(), this)
};
throw;
}
}
finally
{
m_noSkipTokenSet.Remove(NoSkipTokenSet.s_DoWhileBodyNoSkipTokenSet);
}
if (JSToken.While != m_currentToken.Token)
{
ReportError(JSError.NoWhile);
}
whileContext = m_currentToken.Clone();
doCtx.UpdateWith(whileContext);
GetNextToken();
if (JSToken.LeftParenthesis != m_currentToken.Token)
{
ReportError(JSError.NoLeftParenthesis);
}
GetNextToken();
// catch here so the body of the do_while is not thrown away
m_noSkipTokenSet.Add(NoSkipTokenSet.s_BlockConditionNoSkipTokenSet);
try
{
condition = ParseExpression();
if (JSToken.RightParenthesis != m_currentToken.Token)
{
ReportError(JSError.NoRightParenthesis);
doCtx.UpdateWith(condition.Context);
}
else
{
doCtx.UpdateWith(m_currentToken);
}
GetNextToken();
}
catch (RecoveryTokenException exc)
{
// make up a condition
if (exc._partiallyComputedNode != null)
condition = exc._partiallyComputedNode;
else
condition = new ConstantWrapper(false, PrimitiveType.Boolean, CurrentPositionContext(), this);
if (IndexOfToken(NoSkipTokenSet.s_BlockConditionNoSkipTokenSet, exc) == -1)
{
exc._partiallyComputedNode = new DoWhile(doCtx, this)
{
Body = AstNode.ForceToBlock(body),
WhileContext = whileContext,
Condition = condition
};
throw;
}
else
{
if (JSToken.RightParenthesis == m_currentToken.Token)
GetNextToken();
}
}
finally
{
m_noSkipTokenSet.Remove(NoSkipTokenSet.s_BlockConditionNoSkipTokenSet);
}
if (JSToken.Semicolon == m_currentToken.Token)
{
// JScript 5 allowed statements like
// do{print(++x)}while(x<10) print(0)
// even though that does not strictly follow the automatic semicolon insertion
// rules for the required semi after the while(). For backwards compatibility
// we should continue to support this.
terminatorContext = m_currentToken.Clone();
GetNextToken();
}
}
finally
{
m_blockType.RemoveAt(m_blockType.Count - 1);
}
// if this is an assignment, throw a warning in case the developer
// meant to use == instead of =
// but no warning if the condition is wrapped in parens.
var binOp = condition as BinaryOperator;
if (binOp != null && binOp.OperatorToken == JSToken.Assign)
{
condition.Context.HandleError(JSError.SuspectAssignment);
}
return new DoWhile(doCtx, this)
{
Body = AstNode.ForceToBlock(body),
WhileContext = whileContext,
Condition = condition,
TerminatingContext = terminatorContext
};
}
private static int RelocateFunction(Block block, int insertAt, FunctionObject funcDecl)
{
if (block[insertAt] != funcDecl)
{
// technically function declarations can only be direct children of the program or a function block.
// and since we are passing in such a block, the parent of the function declaration better be that
// block. If it isn't, we don't want to move it because it's not in an allowed place, and different
// browsers treat that situation differently. Some browsers would process such funcdecls as if
// they were a direct child of the main block. Others will treat it like a function expression with
// an external name, and only assign the function to the name if that line of code is actually
// executed. So since there's a difference, just leave them as-is and only move valid funcdecls.
if (funcDecl.Parent == block)
{
// remove the function from it's parent, which will take it away from where it is right now.
funcDecl.Parent.ReplaceChild(funcDecl, null);
// now insert it into the block at the new location, incrementing the location so the next function
// will be inserted after it. It is important that they be in the same order as the source, or the semantics
// will change when there are functions with the same name.
block.Insert(insertAt++, funcDecl);
}
}
else
{
// we're already in the right place. Just increment the pointer to move to the next position
// for next time
++insertAt;
}
// return the new position
return insertAt;
}
//---------------------------------------------------------------------------------------
// ParseWhileStatement
//
// WhileStatement :
// 'while' '(' Expression ')' Statement
//---------------------------------------------------------------------------------------
private WhileNode ParseWhileStatement()
{
Context whileCtx = m_currentToken.Clone();
AstNode condition = null;
AstNode body = null;
m_blockType.Add(BlockType.Loop);
try
{
GetNextToken();
if (JSToken.LeftParenthesis != m_currentToken.Token)
{
ReportError(JSError.NoLeftParenthesis);
}
GetNextToken();
m_noSkipTokenSet.Add(NoSkipTokenSet.s_BlockConditionNoSkipTokenSet);
try
{
condition = ParseExpression();
if (JSToken.RightParenthesis != m_currentToken.Token)
{
ReportError(JSError.NoRightParenthesis);
whileCtx.UpdateWith(condition.Context);
}
else
whileCtx.UpdateWith(m_currentToken);
GetNextToken();
}
catch (RecoveryTokenException exc)
{
if (IndexOfToken(NoSkipTokenSet.s_BlockConditionNoSkipTokenSet, exc) == -1)
{
// abort the while there is really no much to do here
exc._partiallyComputedNode = null;
throw;
}
else
{
// make up a condition
if (exc._partiallyComputedNode != null)
condition = exc._partiallyComputedNode;
else
condition = new ConstantWrapper(false, PrimitiveType.Boolean, CurrentPositionContext(), this);
if (JSToken.RightParenthesis == m_currentToken.Token)
GetNextToken();
}
}
finally
{
m_noSkipTokenSet.Remove(NoSkipTokenSet.s_BlockConditionNoSkipTokenSet);
}
// if this is an assignment, throw a warning in case the developer
// meant to use == instead of =
// but no warning if the condition is wrapped in parens.
var binOp = condition as BinaryOperator;
if (binOp != null && binOp.OperatorToken == JSToken.Assign)
{
condition.Context.HandleError(JSError.SuspectAssignment);
}
// if the statements aren't withing curly-braces, throw a possible error
if (JSToken.LeftCurly != m_currentToken.Token)
{
ReportError(JSError.StatementBlockExpected, CurrentPositionContext(), true);
}
try
{
// parse a Statement, not a SourceElement
body = ParseStatement(false);
}
catch (RecoveryTokenException exc)
{
if (exc._partiallyComputedNode != null)
body = exc._partiallyComputedNode;
else
body = new Block(CurrentPositionContext(), this);
exc._partiallyComputedNode = new WhileNode(whileCtx, this)
{
Condition = condition,
Body = AstNode.ForceToBlock(body)
};
throw;
}
}
finally
{
m_blockType.RemoveAt(m_blockType.Count - 1);
}
return new WhileNode(whileCtx, this)
{
Condition = condition,
Body = AstNode.ForceToBlock(body)
};
}
// unnest any child blocks
private void UnnestBlocks(Block node)
{
// walk the list of items backwards -- if we come
// to any blocks, unnest the block recursively.
// Remove any empty statements as well.
// We walk backwards because we could be adding any number of statements
// and we don't want to have to modify the counter.
for (int ndx = node.Count - 1; ndx >= 0; --ndx)
{
var nestedBlock = node[ndx] as Block;
if (nestedBlock != null)
{
// unnest recursively
UnnestBlocks(nestedBlock);
// if the block has a block scope, then we can't really unnest it
// without merging lexical scopes
if (nestedBlock.BlockScope == null)
{
// remove the nested block
node.RemoveAt(ndx);
// then start adding the statements in the nested block to our own.
// go backwards so we can just keep using the same index
node.InsertRange(ndx, nestedBlock.Children);
}
}
else if (node[ndx] is EmptyStatement)
{
// remove empty statements (lone semicolons)
node.RemoveAt(ndx);
}
else if (ndx > 0)
{
// see if the previous node is a conditional-compilation comment, because
// we will also combine adjacent those
var previousComment = node[ndx - 1] as ConditionalCompilationComment;
if (previousComment != null)
{
ConditionalCompilationComment thisComment = node[ndx] as ConditionalCompilationComment;
if (thisComment != null)
{
// two adjacent conditional comments -- combine them into the first.
previousComment.Statements.Append(thisComment.Statements);
// and remove the second one (which is now a duplicate)
node.RemoveAt(ndx);
}
}
}
}
}
//---------------------------------------------------------------------------------------
// ParseWithStatement
//
// WithStatement :
// 'with' '(' Expression ')' Statement
//---------------------------------------------------------------------------------------
private WithNode ParseWithStatement()
{
Context withCtx = m_currentToken.Clone();
AstNode obj = null;
Block block = null;
m_blockType.Add(BlockType.Block);
try
{
GetNextToken();
if (JSToken.LeftParenthesis != m_currentToken.Token)
ReportError(JSError.NoLeftParenthesis);
GetNextToken();
m_noSkipTokenSet.Add(NoSkipTokenSet.s_BlockConditionNoSkipTokenSet);
try
{
obj = ParseExpression();
if (JSToken.RightParenthesis != m_currentToken.Token)
{
withCtx.UpdateWith(obj.Context);
ReportError(JSError.NoRightParenthesis);
}
else
withCtx.UpdateWith(m_currentToken);
GetNextToken();
}
catch (RecoveryTokenException exc)
{
if (IndexOfToken(NoSkipTokenSet.s_BlockConditionNoSkipTokenSet, exc) == -1)
{
// give up
exc._partiallyComputedNode = null;
throw;
}
else
{
if (exc._partiallyComputedNode == null)
obj = new ConstantWrapper(true, PrimitiveType.Boolean, CurrentPositionContext(), this);
else
obj = exc._partiallyComputedNode;
withCtx.UpdateWith(obj.Context);
if (exc._token == JSToken.RightParenthesis)
GetNextToken();
}
}
finally
{
m_noSkipTokenSet.Remove(NoSkipTokenSet.s_BlockConditionNoSkipTokenSet);
}
// if the statements aren't withing curly-braces, throw a possible error
if (JSToken.LeftCurly != m_currentToken.Token)
{
ReportError(JSError.StatementBlockExpected, CurrentPositionContext(), true);
}
try
{
// parse a Statement, not a SourceElement
AstNode statement = ParseStatement(false);
// but make sure we save it as a block
block = statement as Block;
if (block == null)
{
block = new Block(statement.Context, this);
block.Append(statement);
}
}
catch (RecoveryTokenException exc)
{
if (exc._partiallyComputedNode == null)
{
block = new Block(CurrentPositionContext(), this);
}
else
{
block = exc._partiallyComputedNode as Block;
if (block == null)
{
block = new Block(exc._partiallyComputedNode.Context, this);
block.Append(exc._partiallyComputedNode);
}
}
exc._partiallyComputedNode = new WithNode(withCtx, this)
{
WithObject = obj,
Body = block
};
throw;
}
}
finally
{
m_blockType.RemoveAt(m_blockType.Count - 1);
}
return new WithNode(withCtx, this)
{
WithObject = obj,
Body = block
};
}
public static void Apply(Block block, JSParser parser)
{
// create a new instance of the visitor and apply it to the block
var visitor = new ReorderScopeVisitor(parser);
block.Accept(visitor);
// if there were any module directive prologues we need to promote, do them first
var insertAt = 0;
if (visitor.m_moduleDirectives != null)
{
foreach (var directivePrologue in visitor.m_moduleDirectives)
{
insertAt = RelocateDirectivePrologue(block, insertAt, directivePrologue);
}
}
// Make sure that we skip over any remaining comments and directive prologues.
// we do NOT want to insert anything between the start of the scope and any directive prologues.
while (insertAt < block.Count
&& (block[insertAt] is DirectivePrologue || block[insertAt] is ImportantComment))
{
++insertAt;
}
// first, we want to move all function declarations to the top of this block
if (visitor.m_functionDeclarations != null)
{
foreach (var funcDecl in visitor.m_functionDeclarations)
{
insertAt = RelocateFunction(block, insertAt, funcDecl);
}
}
// special case: if there is only one var statement in the entire scope,
// then just leave it alone because we will only add bytes by moving it around,
// or be byte-neutral at best (no initializers and not in a for-statement).
if (visitor.m_varStatements != null && visitor.m_varStatements.Count > 1)
{
// then we want to move all variable declarations after to the top (after the functions)
foreach (var varStatement in visitor.m_varStatements)
{
insertAt = RelocateVar(block, insertAt, varStatement);
}
}
// then we want to do the same thing for all child functions (declarations AND other)
if (visitor.m_functionDeclarations != null)
{
foreach (var funcDecl in visitor.m_functionDeclarations)
{
Apply(funcDecl.Body, parser);
}
}
if (visitor.m_functionExpressions != null)
{
foreach (var funcExpr in visitor.m_functionExpressions)
{
Apply(funcExpr.Body, parser);
}
}
}
private AstNode ParseSwitchStatement()
{
Context switchCtx = m_currentToken.Clone();
AstNode expr = null;
AstNodeList cases = null;
var braceOnNewLine = false;
Context braceContext = null;
m_blockType.Add(BlockType.Switch);
try
{
// read switch(expr)
GetNextToken();
if (JSToken.LeftParenthesis != m_currentToken.Token)
ReportError(JSError.NoLeftParenthesis);
GetNextToken();
m_noSkipTokenSet.Add(NoSkipTokenSet.s_BlockConditionNoSkipTokenSet);
m_noSkipTokenSet.Add(NoSkipTokenSet.s_SwitchNoSkipTokenSet);
try
{
expr = ParseExpression();
if (JSToken.RightParenthesis != m_currentToken.Token)
{
ReportError(JSError.NoRightParenthesis);
}
GetNextToken();
if (JSToken.LeftCurly != m_currentToken.Token)
{
ReportError(JSError.NoLeftCurly);
}
braceOnNewLine = m_foundEndOfLine;
braceContext = m_currentToken.Clone();
GetNextToken();
}
catch (RecoveryTokenException exc)
{
if (IndexOfToken(NoSkipTokenSet.s_BlockConditionNoSkipTokenSet, exc) == -1
&& IndexOfToken(NoSkipTokenSet.s_SwitchNoSkipTokenSet, exc) == -1)
{
// give up
exc._partiallyComputedNode = null;
throw;
}
else
{
if (exc._partiallyComputedNode == null)
expr = new ConstantWrapper(true, PrimitiveType.Boolean, CurrentPositionContext(), this);
else
expr = exc._partiallyComputedNode;
if (IndexOfToken(NoSkipTokenSet.s_BlockConditionNoSkipTokenSet, exc) != -1)
{
if (exc._token == JSToken.RightParenthesis)
GetNextToken();
if (JSToken.LeftCurly != m_currentToken.Token)
{
ReportError(JSError.NoLeftCurly);
}
braceOnNewLine = m_foundEndOfLine;
braceContext = m_currentToken.Clone();
GetNextToken();
}
}
}
finally
{
m_noSkipTokenSet.Remove(NoSkipTokenSet.s_SwitchNoSkipTokenSet);
m_noSkipTokenSet.Remove(NoSkipTokenSet.s_BlockConditionNoSkipTokenSet);
}
// parse the switch body
cases = new AstNodeList(CurrentPositionContext(), this);
bool defaultStatement = false;
m_noSkipTokenSet.Add(NoSkipTokenSet.s_BlockNoSkipTokenSet);
try
{
while (JSToken.RightCurly != m_currentToken.Token)
{
SwitchCase caseClause = null;
AstNode caseValue = null;
var caseCtx = m_currentToken.Clone();
Context colonContext = null;
m_noSkipTokenSet.Add(NoSkipTokenSet.s_CaseNoSkipTokenSet);
try
{
if (JSToken.Case == m_currentToken.Token)
{
// get the case
GetNextToken();
caseValue = ParseExpression();
}
else if (JSToken.Default == m_currentToken.Token)
{
// get the default
if (defaultStatement)
{
// we report an error but we still accept the default
ReportError(JSError.DupDefault, true);
}
else
{
defaultStatement = true;
}
GetNextToken();
}
else
{
// This is an error, there is no case or default. Assume a default was missing and keep going
defaultStatement = true;
ReportError(JSError.BadSwitch);
}
if (JSToken.Colon != m_currentToken.Token)
{
ReportError(JSError.NoColon);
}
else
{
colonContext = m_currentToken.Clone();
}
// read the statements inside the case or default
GetNextToken();
}
catch (RecoveryTokenException exc)
{
// right now we can only get here for the 'case' statement
if (IndexOfToken(NoSkipTokenSet.s_CaseNoSkipTokenSet, exc) == -1)
{
// ignore the current case or default
exc._partiallyComputedNode = null;
throw;
}
else
{
caseValue = exc._partiallyComputedNode;
if (exc._token == JSToken.Colon)
{
GetNextToken();
}
}
}
finally
{
m_noSkipTokenSet.Remove(NoSkipTokenSet.s_CaseNoSkipTokenSet);
}
m_blockType.Add(BlockType.Block);
try
{
var statements = new Block(m_currentToken.Clone(), this);
m_noSkipTokenSet.Add(NoSkipTokenSet.s_SwitchNoSkipTokenSet);
m_noSkipTokenSet.Add(NoSkipTokenSet.s_StartStatementNoSkipTokenSet);
try
{
while (JSToken.RightCurly != m_currentToken.Token && JSToken.Case != m_currentToken.Token && JSToken.Default != m_currentToken.Token)
{
try
{
// parse a Statement, not a SourceElement
statements.Append(ParseStatement(false));
}
catch (RecoveryTokenException exc)
{
if (exc._partiallyComputedNode != null)
{
statements.Append(exc._partiallyComputedNode);
exc._partiallyComputedNode = null;
}
if (IndexOfToken(NoSkipTokenSet.s_StartStatementNoSkipTokenSet, exc) == -1)
{
throw;
}
}
}
}
catch (RecoveryTokenException exc)
{
if (IndexOfToken(NoSkipTokenSet.s_SwitchNoSkipTokenSet, exc) == -1)
{
caseClause = new SwitchCase(caseCtx, this)
{
CaseValue = caseValue,
ColonContext = colonContext,
Statements = statements
};
cases.Append(caseClause);
throw;
}
}
finally
{
m_noSkipTokenSet.Remove(NoSkipTokenSet.s_StartStatementNoSkipTokenSet);
m_noSkipTokenSet.Remove(NoSkipTokenSet.s_SwitchNoSkipTokenSet);
}
caseCtx.UpdateWith(statements.Context);
caseClause = new SwitchCase(caseCtx, this)
{
CaseValue = caseValue,
ColonContext = colonContext,
Statements = statements
};
cases.Append(caseClause);
}
finally
{
m_blockType.RemoveAt(m_blockType.Count - 1);
}
}
}
catch (RecoveryTokenException exc)
{
if (IndexOfToken(NoSkipTokenSet.s_BlockNoSkipTokenSet, exc) == -1)
{
//save what you can a rethrow
switchCtx.UpdateWith(CurrentPositionContext());
exc._partiallyComputedNode = new Switch(switchCtx, this)
{
Expression = expr,
BraceContext = braceContext,
Cases = cases,
BraceOnNewLine = braceOnNewLine
};
throw;
}
}
finally
{
m_noSkipTokenSet.Remove(NoSkipTokenSet.s_BlockNoSkipTokenSet);
}
switchCtx.UpdateWith(m_currentToken);
GetNextToken();
}
finally
{
m_blockType.RemoveAt(m_blockType.Count - 1);
}
return new Switch(switchCtx, this)
{
Expression = expr,
BraceContext = braceContext,
Cases = cases,
BraceOnNewLine = braceOnNewLine
};
}
public void SwapBranches()
{
Block temp = m_trueBlock;
m_trueBlock = m_falseBlock;
m_falseBlock = temp;
}
private void CombineWithPreviousExpression(Block node, int ndx)
{
IfNode ifNode;
ForNode forNode;
WhileNode whileNode;
ReturnNode returnNode;
if (node[ndx].IsExpression)
{
CombineTwoExpressions(node, ndx);
}
else if ((returnNode = node[ndx] as ReturnNode) != null)
{
CombineReturnWithExpression(node, ndx, returnNode);
}
else if ((forNode = node[ndx] as ForNode) != null)
{
CombineForNodeWithExpression(node, ndx, forNode);
}
else if ((ifNode = node[ndx] as IfNode) != null)
{
// transform: expr;if(cond)... => if(expr,cond)...
// combine the previous expression with the if-condition via comma, then delete
// the previous statement.
ifNode.Condition = CommaOperator.CombineWithComma(null, m_parser, node[ndx - 1], ifNode.Condition);
node.RemoveAt(ndx - 1);
}
else if ((whileNode = node[ndx] as WhileNode) != null
&& m_parser.Settings.IsModificationAllowed(TreeModifications.ChangeWhileToFor))
{
// transform: expr;while(cond)... => for(expr;cond;)...
// zero-sum, and maybe a little worse for performance because of the nop iterator,
// but combines two statements into one, which may have savings later on.
var initializer = node[ndx - 1];
node[ndx] = new ForNode(null, m_parser)
{
Initializer = initializer,
Condition = whileNode.Condition,
Body = whileNode.Body
};
node.RemoveAt(ndx - 1);
}
}
