/// <summary>
/// For the given binding node, return a collection of individual lookup
/// nodes that represent the names being referenced.
/// </summary>
/// <param name="node">binding node</param>
/// <returns>collection of Lookup nodes</returns>
public static IList<LookupExpression> References(AstNode node)
{
var visitor = new BindingsVisitor();
if (node != null)
{
node.Accept(visitor);
}
return visitor.m_lookups;
}
/// <summary>
/// For the given binding node, return a collection of individual INameDeclaration
/// nodes that represent the names being declared for this binding element.
/// </summary>
/// <param name="node">binding node</param>
/// <returns>collection of INameDeclaration nodes</returns>
public static IList<BindingIdentifier> Bindings(AstNode node)
{
var visitor = new BindingsVisitor();
if (node != null)
{
node.Accept(visitor);
}
return visitor.m_bindings;
}
private static int RelocateForInVar(BlockStatement block, int insertAt, VarDeclaration varStatement, ForInStatement forIn)
{
// there should only be one decl in the for-in var statement. There should not be any initializer.
// If not, then ignore it
VariableDeclaration varDecl;
if (varStatement.Count == 1 && (varDecl = varStatement[0]).Initializer == null)
{
// if there are more than three names, then we don't want to move them
var bindingNames = BindingsVisitor.Bindings(varDecl.Binding);
//if (bindingNames.Count < 3)
{
// replace the varStatement in the for-in with a reference version of the binding
forIn.Variable = BindingTransform.FromBinding(varDecl.Binding);
// if this is a simple binding identifier, then leave it as-is. Otherwise we
// need to flatten it for the move to the front of the scope.
if (!(varDecl.Binding is BindingIdentifier))
{
// then flatten all the name in the binding and add them to the
var first = true;
foreach (var declName in bindingNames)
{
if (first)
{
varStatement[0] = new VariableDeclaration(declName.Context)
{
Binding = new BindingIdentifier(declName.Context)
{
Name = declName.Name,
VariableField = declName.VariableField
}
};
first = false;
}
else
{
// otherwise we want to insert a new one at the current position + 1
varStatement.Append(new VariableDeclaration(declName.Context)
{
Binding = new BindingIdentifier(declName.Context)
{
Name = declName.Name,
VariableField = declName.VariableField
}
});
}
}
}
// then move the var statement to the front of the scope
// 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
var existingVar = block[insertAt] as VarDeclaration;
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
{
// insert it at the insert point
block.Insert(insertAt, varStatement);
}
}
}
return(insertAt);
}
private static int RelocateVar(BlockStatement block, int insertAt, VarDeclaration varStatement)
{
var forInParent = varStatement.Parent as ForInStatement;
if (forInParent != null)
{
insertAt = ReorderScopeVisitor.RelocateForInVar(block, insertAt, varStatement, forInParent);
}
else
{
// 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.
ForStatement forStatement;
var existingVar = block[insertAt] as VarDeclaration;
if (existingVar != null && block[insertAt + 1] == varStatement)
{
// two var-s one right after the other.
// just append our vardecls to the insertion point, then delete our statement
existingVar.Append(varStatement);
block.RemoveAt(insertAt + 1);
}
else if (existingVar != null &&
(forStatement = varStatement.Parent as ForStatement) != null &&
forStatement.Initializer == varStatement &&
forStatement == block[insertAt + 1])
{
// this var statement is the initializer of a for-statement, which is
// immediately after the var we would insert our vardecls into.
// rather than moving our vardecls into the outside var-statement, let's
// move the outside var-statement into our for-statement.
varStatement.InsertAt(0, existingVar);
block.RemoveAt(insertAt);
}
else
{
// iterate through the decls and count how many have initializers
var initializerCount = 0;
for (var ndx = 0; ndx < varStatement.Count; ++ndx)
{
// count the number of vardecls with initializers
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)
{
// 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;
var reference = BindingTransform.FromBinding(varDecl.Binding);
if (varDecl.IsCCSpecialCase)
{
// we don't want to add the special-case to the binary operator class,
// so just create a copy of the vardecl for this location, using a reference
// for the "binding"
assignments.Add(new VariableDeclaration(varDecl.Context)
{
Binding = reference,
AssignContext = varDecl.AssignContext,
Initializer = initializer,
IsCCSpecialCase = true,
UseCCOn = varDecl.UseCCOn,
TerminatingContext = varDecl.TerminatingContext
});
}
else
{
assignments.Add(new BinaryExpression(varDecl.Context)
{
Operand1 = reference,
Operand2 = initializer,
OperatorToken = JSToken.Assign,
OperatorContext = varDecl.AssignContext
});
}
}
// if the vardecl we are moving isn't a binding pattern, we need to
// break it down into a simple list of names.
if (!(varDecl.Binding is BindingIdentifier))
{
// place the original vardecl with the first one
var first = true;
foreach (var declName in BindingsVisitor.Bindings(varDecl.Binding))
{
if (first)
{
varStatement[ndx] = new VariableDeclaration(declName.Context)
{
Binding = new BindingIdentifier(declName.Context)
{
Name = declName.Name,
VariableField = declName.VariableField
}
};
first = false;
}
else
{
// otherwise we want to insert a new one at the current position + 1
varStatement.InsertAt(++ndx, new VariableDeclaration(declName.Context)
{
Binding = new BindingIdentifier(declName.Context)
{
Name = declName.Name,
VariableField = declName.VariableField
}
});
}
}
}
}
// 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 = CommaExpression.CombineWithComma(expression.Context.FlattenToStart(), 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.
// 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);
}