//---------------------------------------------------------------------------------------
// ParseSwitchStatement
//
// SwitchStatement :
// 'switch' '(' Expression ')' '{' CaseBlock '}'
//
// CaseBlock :
// CaseList DefaultCaseClause CaseList
//
// CaseList :
// <empty> |
// CaseClause CaseList
//
// CaseClause :
// 'case' Expression ':' OptionalStatements
//
// DefaultCaseClause :
// <empty> |
// 'default' ':' OptionalStatements
//---------------------------------------------------------------------------------------
private AstNode ParseSwitchStatement()
{
Context switchCtx = m_currentToken.Clone();
AstNode expr = null;
AstNodeList cases = 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);
}
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);
}
GetNextToken();
}
}
}
finally
{
m_noSkipTokenSet.Remove(NoSkipTokenSet.s_SwitchNoSkipTokenSet);
m_noSkipTokenSet.Remove(NoSkipTokenSet.s_BlockConditionNoSkipTokenSet);
}
// parse the switch body
cases = new AstNodeList(m_currentToken.Clone(), this);
bool defaultStatement = false;
m_noSkipTokenSet.Add(NoSkipTokenSet.s_BlockNoSkipTokenSet);
try
{
while (JSToken.RightCurly != m_currentToken.Token)
{
SwitchCase caseClause = null;
AstNode caseValue = null;
Context caseCtx = m_currentToken.Clone();
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);
}
// 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
{
Block 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, statements);
cases.Append(caseClause);
throw;
}
}
finally
{
m_noSkipTokenSet.Remove(NoSkipTokenSet.s_StartStatementNoSkipTokenSet);
m_noSkipTokenSet.Remove(NoSkipTokenSet.s_SwitchNoSkipTokenSet);
}
if (JSToken.RightCurly == m_currentToken.Token)
{
statements.Context.UpdateWith(m_currentToken);
}
caseCtx.UpdateWith(statements.Context);
caseClause = new SwitchCase(caseCtx, this, caseValue, 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, expr, cases);
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, expr, cases);
}