public override AstNode Visit(AssignmentExpression node)
{
// Get the variable and value expression.
Expression variable = node.GetVariable();
Expression value = node.GetValue();
// Visit them.
variable.Accept(this);
value.Accept(this);
// Get their types.
IChelaType variableType = variable.GetNodeType();
IChelaType valueType = value.GetNodeType();
// Set the node type.
node.SetNodeType(variableType);
// The variable must be a reference.
if(!variableType.IsReference())
Error(node, "trying to set something that isn't a reference.");
// Check the variable is not a constant.
variableType = DeReferenceType(variableType);
if(variableType.IsConstant())
Error(node, "cannot modify constants.");
// Check for the read-only constraint.
Variable variableSlot = variable.GetNodeValue() as Variable;
if(variableSlot != null && variableSlot.IsReadOnly())
CheckReadOnlyConstraint(node, variableSlot);
// Set the coercion type.
node.SetCoercionType(variableType);
// Check the type compatibility.
//System.Console.WriteLine("{0}->{1}", valueType, variableType);
if(variableType != valueType &&
Coerce(node, variableType, valueType, value.GetNodeValue()) != variableType)
{
// Delay integer constants casting.
if(valueType.IsConstant())
{
valueType = DeConstType(valueType);
if(valueType.IsInteger() &&
valueType != ChelaType.GetBoolType() &&
valueType != ChelaType.GetCharType())
node.DelayedCoercion = true;
}
if(!node.DelayedCoercion)
Error(value, "cannot implicitly cast from {0} to {1}.",
valueType.GetDisplayName(), variableType.GetDisplayName());
}
return node;
}
