private void ProcessTerm(NodeBase term)
{
Expect(term, NodeType.Term);
Queue <NodeBase> children = GetChildren(term);
if (PeekValue(children) == "(")
{
Expect(children.Dequeue(), NodeType.Symbol, "(");
ProcessExpression(children.Dequeue());
Expect(children.Dequeue(), NodeType.Symbol, ")");
}
else
{
NodeType?type = PeekType(children);
switch (type)
{
case NodeType.IntegerConstant:
vmWriter.PushConstant(GetValue(children.Dequeue()));
break;
case NodeType.StringConstant:
vmWriter.PushStringConstant(GetValue(children.Dequeue()));
break;
case NodeType.Keyword:
string keywordValue = GetValue(children.Dequeue());
switch (keywordValue)
{
case "true":
vmWriter.PushTrue();
break;
case "false":
vmWriter.PushFalse();
break;
case "this":
vmWriter.PushThis();
break;
case "null":
vmWriter.PushConstant("0");
break;
default:
throw GenerateNotImplementedException(keywordValue);
}
break;
case NodeType.Symbol:
string unaryOp = Expect(children.Dequeue(), NodeType.Symbol);
ProcessTerm(children.Dequeue());
vmWriter.Unary(unaryOp);
break;
case NodeType.Identifier:
Identifier identifier = GetIdentifier(children.Dequeue());
if (PeekValue(children) == "." || PeekValue(children) == "(")
{
ProcessSubroutineCall(children, identifier);
}
else if (PeekValue(children) == "[")
{
Expect(children.Dequeue(), NodeType.Symbol, "[");
ProcessExpression(children.Dequeue());
vmWriter.Push(identifier);
vmWriter.AccessArray();
}
else
{
vmWriter.Push(identifier);
}
break;
default:
throw GenerateNotImplementedException(type.ToString());
}
}
}