public override AstNode Visit(CaseLabel node)
{
// Get the constant expression.
Expression constant = node.GetConstant();
// Expand it.
if(constant != null)
{
constant = (Expression)constant.Accept(this);
node.SetConstant(constant);
// Get the constant value.
IChelaType coercionType = currentSwitch.GetCoercionType();
ConstantValue constantValue = (ConstantValue)constant.GetNodeValue();
constantValue = constantValue.Cast(coercionType);
// Make sure the case definition is unique.
IDictionary<ConstantValue, CaseLabel> caseDict = currentSwitch.CaseDictionary;
CaseLabel oldCase;
if(caseDict.TryGetValue(constantValue, out oldCase))
Error(node, "previous definition of the same case in {0}.", oldCase.GetPosition().ToString());
// Register the case.
caseDict.Add(constantValue, node);
}
// Visit the children.
VisitList(node.GetChildren());
return node;
}
public override AstNode Visit(CaseLabel node)
{
// Get the constant expr.
Expression constantExpr = node.GetConstant();
if(constantExpr != null)
{
// Visit the constant expression.
constantExpr.Accept(this);
// Perform coercion.
IChelaType constantType = constantExpr.GetNodeType();
IChelaType coercionType = node.GetCoercionType();
if(Coerce(coercionType, constantType) != coercionType)
Error(node, "incompatible constant type {0} -> {1}.", constantType.GetDisplayName(), coercionType.GetDisplayName());
// Delay the case registration to the constant expansion pass.
}
else
{
// Make sure there's only one default statement.
AstNode oldDefault = currentSwitch.GetDefaultCase();
if(oldDefault != null)
Error(node, "only one default case is allowed in a switch statement. Previous definition in {0}", oldDefault.GetPosition().ToString());
// Register the default case.
currentSwitch.SetDefaultCase(node);
}
// Visit the children statements.
AstNode children = node.GetChildren();
VisitList(node.GetChildren());
// The last case cannot be empty.
if(children == null && node.GetNext() == null)
Error(node, "last case in a switch cannot be empty.");
return node;
}