// Parse a statement.
private JNode Statement()
{
JNode stmt = null;
JNode temp, temp2;
Context save;
// Save the current context, so that we know
// where the statement starts.
save = tokenInfo.MakeCopy();
// Determine what kind of statement to parse.
switch(token)
{
case JSToken.LeftCurly:
{
// Compound statement encountered.
NextToken();
while(token != JSToken.RightCurly &&
token != JSToken.EndOfFile)
{
temp = Statement();
stmt = Support.CreateCompound(stmt, temp);
}
if(stmt == null)
{
stmt = new JEmpty(Context.BuildRange
(save, tokenInfo));
}
else if(stmt is JCompound)
{
// Make sure the compound statement includes
// the curly brackets.
stmt.context = Context.BuildRange
(save, tokenInfo);
}
if(token == JSToken.EndOfFile)
{
SyntaxError("`}' expected");
}
else
{
NextToken();
}
}
break;
case JSToken.Semicolon:
{
// Bare semi-colon for an empty statement.
stmt = new JEmpty(save);
NextToken();
}
break;
case JSToken.If:
{
// Parse an "if" statement.
NextToken();
temp = BracketedExpression();
stmt = Statement();
if(token != JSToken.Else)
{
stmt = new JIf(Context.BuildRange
(save, stmt.context),
temp, stmt, null);
}
else
{
NextToken();
temp2 = Statement();
stmt = new JIf(Context.BuildRange
(save, temp2.context),
temp, stmt, temp2);
}
}
break;
case JSToken.While:
{
// Parse a "while" statement.
NextToken();
temp = BracketedExpression();
stmt = Statement();
stmt = new JWhile(Context.BuildRange
(save, stmt.context),
temp, stmt);
}
break;
case JSToken.Do:
{
// Parse a "do" statement.
NextToken();
stmt = Statement();
Expect(JSToken.While, "`while' expected");
temp = BracketedExpression();
stmt = new JDo(Context.BuildRange(save, temp.context),
stmt, temp);
}
break;
case JSToken.Continue:
{
// Parse a "continue" statement.
NextToken();
if(HaveSemiColon())
{
// Continue with no label.
stmt = new JContinue(save, null);
MatchSemiColon();
}
else if(token == JSToken.Identifier)
{
// Extract the label.
stmt = new JContinue
(Context.BuildRange(save, tokenInfo),
scanner.GetIdentifierName());
NextToken();
MatchSemiColon();
}
else
{
SyntaxError("`continue' label expected");
}
}
break;
case JSToken.Break:
{
// Parse a "break" statement.
NextToken();
if(HaveSemiColon())
{
// Break with no label.
stmt = new JBreak(save, null);
MatchSemiColon();
}
else if(token == JSToken.Identifier)
{
// Extract the label.
stmt = new JBreak
(Context.BuildRange(save, tokenInfo),
scanner.GetIdentifierName());
NextToken();
MatchSemiColon();
}
else
{
SyntaxError("`break' label expected");
}
}
break;
case JSToken.Return:
{
// Parse a "return" statement.
NextToken();
if(HaveSemiColon())
{
// Return with no expression.
stmt = new JReturn(save);
MatchSemiColon();
}
else
{
// Return with an expression.
temp = Expression();
stmt = new JReturnExpr
(Context.BuildRange(save, temp.context), temp);
MatchSemiColon();
}
}
break;
case JSToken.Throw:
{
// Parse a "throw" statement.
NextToken();
if(HaveSemiColon())
{
// Throw with missing expression.
SyntaxError("expression expected");
}
else
{
// Parse the expression for the "throw".
temp = Expression();
stmt = new JThrow
(Context.BuildRange(save, temp.context), temp);
MatchSemiColon();
}
}
break;
case JSToken.With:
{
// Parse a "with" statement.
NextToken();
temp = BracketedExpression();
stmt = Statement();
stmt = new JWith(Context.BuildRange(save, stmt.context),
temp, stmt);
}
break;
case JSToken.Var:
{
// Parse a variable declaration.
NextToken();
stmt = VariableDeclarationList(false);
MatchSemiColon();
}
break;
case JSToken.For:
{
// Parse a "for" statement.
JNode init, cond, incr;
NextToken();
Expect(JSToken.LeftParen, "`(' expected");
// Parse the initialization expression.
if(token == JSToken.Var)
{
// Starts with a variable declaration.
NextToken();
init = VariableDeclarationList(true);
}
else if(token == JSToken.Semicolon)
{
// No initialization expression.
init = null;
}
else
{
// No variable declarations.
init = ExpressionNoIn();
init = new JExprStmt
(init.context.MakeCopy(), init);
}
// Is this the normal or "in" form?
if(token != JSToken.In)
{
Expect(JSToken.Semicolon, "`;' expected");
if(token != JSToken.Semicolon)
{
cond = Expression();
}
else
{
cond = null;
}
Expect(JSToken.Semicolon, "`;' expected");
if(token != JSToken.RightParen)
{
incr = Expression();
}
else
{
incr = null;
}
Expect(JSToken.RightParen, "`)' expected");
temp = Statement();
stmt = new JFor(Context.BuildRange
(save, temp.context),
init, cond, incr, temp);
}
else
{
if(init is JCompound)
{
SyntaxError("only one variable name can be " +
"used with for(var ... in ...)");
}
else if(init != null && !(init is JVarDecl))
{
CheckLeftHandSideExpression(init);
}
NextToken();
cond = Expression();
Expect(JSToken.RightParen, "`)' expected");
temp = Statement();
stmt = new JForIn(Context.BuildRange
(save, temp.context),
init, cond, temp);
}
}
break;
case JSToken.Switch:
{
// Parse a "switch" statement.
NextToken();
temp = BracketedExpression();
Expect(JSToken.LeftCurly, "`{' expected");
stmt = CaseBlock();
Expect(JSToken.RightCurly, "`}' expected");
if(stmt != null)
{
stmt = new JSwitch(Context.BuildRange
(save, stmt.context),
temp, stmt);
}
else
{
// No clauses, so evaluate the expression
// for its side-effects only.
stmt = new JExprStmt
(temp.context.MakeCopy(), temp);
}
}
break;
case JSToken.Try:
{
// Parse a "try" statement.
String catchName = null;
JNode catchClause = null;
JNode finallyClause = null;
NextToken();
stmt = Block();
if(token == JSToken.Catch)
{
NextToken();
Expect(JSToken.LeftParen, "`(' expected");
if(token != JSToken.Identifier)
{
SyntaxError("identifier expected");
}
catchName = scanner.GetIdentifierName();
NextToken();
Expect(JSToken.RightParen, "`)' expected");
catchClause = Block();
}
else if(token != JSToken.Finally)
{
SyntaxError("`catch' or `finally' expected");
}
if(token == JSToken.Finally)
{
NextToken();
finallyClause = Block();
save = Context.BuildRange
(save, finallyClause.context);
}
else
{
save = Context.BuildRange
(save, catchClause.context);
}
stmt = new JTry(save, stmt, catchName,
catchClause, finallyClause);
}
break;
default:
{
// Should be an expression.
temp = StatementExpression();
if(token == JSToken.Colon)
{
// The expression is followed by a colon,
// so it is probably a label.
if(!(temp is JIdentifier))
{
SyntaxError("invalid statement label");
}
NextToken();
stmt = Statement();
Support.AddLabel
(((JIdentifier)temp).name, stmt);
stmt.context = Context.BuildRange
(save, stmt.context);
}
else
{
// Ordinary expression statement.
stmt = new JExprStmt
(Context.BuildRange(save, temp.context), temp);
MatchSemiColon();
}
}
break;
}
// Return the statement to the caller.
return stmt;
}
// Parse a list of statements within a "switch" case block.
private JNode CaseStatementList()
{
JNode stmt = null;
JNode stmt2;
while(token != JSToken.RightCurly &&
token != JSToken.Case &&
token != JSToken.Default)
{
stmt2 = Statement();
stmt = Support.CreateCompound(stmt, stmt2);
}
if(stmt == null)
{
stmt = new JEmpty(tokenInfo.MakeCopy());
}
return stmt;
}