public LabelledStatement(List <string> set, Statement labelled)
{
labels = set;
Labelled = labelled;
}
public override Statement ParseNoNewContext(Parser parser)
{
// Consume the for keyword.
parser.Expect(KeywordToken.For);
// Read the left parenthesis.
parser.Expect(PunctuatorToken.LeftParenthesis);
// The initialization statement.
Statement initializationStatement = null;
// The type of for statement.
ForStatementType type = ForStatementType.Unknown;
// The for-in and for-of expressions need a variable to assign to. Is null for a regular for statement.
IReferenceExpression forInOfReference = null;
if (parser.nextToken == KeywordToken.Var || parser.nextToken == KeywordToken.Let || parser.nextToken == KeywordToken.Const)
{
bool isVar = (parser.nextToken == KeywordToken.Var);
// Read past the var/let/const token.
parser.Expect(parser.nextToken);
Scope scope = isVar?parser.currentVarScope : parser.currentLetScope;
// There can be multiple initializers (but not for for-in statements).
var varLetConstStatement = new VarStatement(scope);
initializationStatement = parser.Labels(varLetConstStatement);
while (true)
{
var declaration = new VariableDeclaration();
// The next token must be a variable name.
declaration.VariableName = parser.ExpectIdentifier();
parser.ValidateVariableName(declaration.VariableName);
// Add the variable to the current function's list of local variables.
parser.currentVarScope.AddVariable(declaration.VariableName, null,
parser.context == CodeContext.Function ? null : new LiteralExpression(Undefined.Value));
// The next token is either an equals sign (=), a semi-colon, a comma, or the "in" keyword.
if (parser.nextToken == PunctuatorToken.Assignment)
{
// Read past the equals token (=).
parser.Expect(PunctuatorToken.Assignment);
// Read the setter expression.
declaration.InitExpression = parser.ParseExpression(PunctuatorToken.Semicolon, PunctuatorToken.Comma);
// This must be a regular for statement.
type = ForStatementType.For;
}
// Add the declaration to the initialization statement.
varLetConstStatement.Declarations.Add(declaration);
if (parser.nextToken == PunctuatorToken.Semicolon)
{
// This is a regular for statement.
break;
}
else if (parser.nextToken == KeywordToken.In && type == ForStatementType.Unknown)
{
// This is a for-in statement.
forInOfReference = new NameExpression(scope, declaration.VariableName);
type = ForStatementType.ForIn;
break;
}
else if (parser.nextToken == IdentifierToken.Of && type == ForStatementType.Unknown)
{
// This is a for-of statement.
forInOfReference = new NameExpression(scope, declaration.VariableName);
type = ForStatementType.ForOf;
break;
}
else if (parser.nextToken != PunctuatorToken.Comma)
{
throw new JavaScriptException(parser.engine, "SyntaxError", string.Format("Unexpected token {0}", Token.ToText(parser.nextToken)), parser.LineNumber, parser.SourcePath);
}
// Read past the comma token.
parser.Expect(PunctuatorToken.Comma);
// Multiple initializers are not allowed in for-in statements.
type = ForStatementType.For;
}
}
else
{
// Not a var initializer - can be a simple variable name then "in" or any expression ending with a semi-colon.
// The expression can be empty.
if (parser.nextToken != PunctuatorToken.Semicolon)
{
// Parse an expression.
var initializationExpression = parser.ParseExpression(PunctuatorToken.Semicolon, KeywordToken.In, IdentifierToken.Of);
// Record debug info for the expression.
initializationStatement = new ExpressionStatement(initializationExpression);
if (parser.nextToken == KeywordToken.In)
{
// This is a for-in statement.
if ((initializationExpression is IReferenceExpression) == false)
{
throw new JavaScriptException(parser.engine, "SyntaxError", "Invalid left-hand side in for-in", parser.LineNumber, parser.SourcePath);
}
forInOfReference = (IReferenceExpression)initializationExpression;
}
else if (parser.nextToken == IdentifierToken.Of)
{
// This is a for-of statement.
if ((initializationExpression is IReferenceExpression) == false)
{
throw new JavaScriptException(parser.engine, "SyntaxError", "Invalid left-hand side in for-of", parser.LineNumber, parser.SourcePath);
}
forInOfReference = (IReferenceExpression)initializationExpression;
type = ForStatementType.ForOf;
}
}
}
if (type == ForStatementType.ForIn)
{
// for (x in y)
// for (var x in y)
var result = new ForInStatement();
var labelled = parser.Labels(result);
result.Variable = forInOfReference;
// Consume the "in".
parser.Expect(KeywordToken.In);
// Parse the right-hand-side expression.
result.TargetObject = parser.ParseExpression(PunctuatorToken.RightParenthesis);
// Read the right parenthesis.
parser.Expect(PunctuatorToken.RightParenthesis);
// Read the statements that will be executed in the loop body.
result.Body = parser.ParseStatement();
return(labelled);
}
else if (type == ForStatementType.ForOf)
{
// for (x of y)
// for (var x of y)
var result = new ForOfStatement();
var labelled = parser.Labels(result);
result.Variable = forInOfReference;
// Consume the "of".
parser.Expect(IdentifierToken.Of);
// Parse the right-hand-side expression.
result.TargetObject = parser.ParseExpression(PunctuatorToken.RightParenthesis, PunctuatorToken.Comma); // Comma is not allowed.
// Read the right parenthesis.
parser.Expect(PunctuatorToken.RightParenthesis);
// Read the statements that will be executed in the loop body.
result.Body = parser.ParseStatement();
return(labelled);
}
else
{
var result = new ForStatement();
var labelled = parser.Labels(result);
// Set the initialization statement.
if (initializationStatement != null)
{
result.InitStatement = initializationStatement;
}
// Read the semicolon.
parser.Expect(PunctuatorToken.Semicolon);
// Parse the optional condition expression.
// Note: if the condition is omitted then it is considered to always be true.
if (parser.nextToken != PunctuatorToken.Semicolon)
{
result.ConditionStatement = new ExpressionStatement(parser.ParseExpression(PunctuatorToken.Semicolon));
}
// Read the semicolon.
// Note: automatic semicolon insertion never inserts a semicolon in the header of a
// for statement.
parser.Expect(PunctuatorToken.Semicolon);
// Parse the optional increment expression.
if (parser.nextToken != PunctuatorToken.RightParenthesis)
{
result.IncrementStatement = new ExpressionStatement(parser.ParseExpression(PunctuatorToken.RightParenthesis));
}
// Read the right parenthesis.
parser.Expect(PunctuatorToken.RightParenthesis);
// Read the statements that will be executed in the loop body.
result.Body = parser.ParseStatement();
return(labelled);
}
}
