public static List <CollectedIndex> Indices(MatchIterator iterator)
{
List <CollectedIndex> indices = new List <CollectedIndex>();
iterator.AssertNext();
while (iterator.HasNext)
{
iterator.AssertKeySymbol(Symbols.OpenSquareBracket, out Token open);
iterator.AssertExpression(out Expression index);
iterator.AssertKeySymbol(Symbols.CloseSquareBracket, out Token close);
CollectedIndex entry = new CollectedIndex
{
Open = open,
Index = index,
Close = close
};
indices.Add(entry);
}
return(indices);
}
public static Expression Create(MatchIterator iterator)
{
LinkedList <object> items = new LinkedList <object>();
iterator.AssertNext();
// postfix unary operators are not supported here
// (Like i--, etc)
// I don't think they are really needed for sprak, and defaulting
// to assuming prefix simplifies things.
while (true)
{
items.AddLast(GetValue(iterator));
if (iterator.AtEnd())
{
break;
}
iterator.AssertTokenType(TokenType.Operator, out Token op);
items.AddLast(op);
if (iterator.AtEnd())
{
break;
}
}
void ParseOperatorToken(LinkedListNode <object> opNode)
{
Token token = (Token)opNode.Value;
LinkedListNode <object> leftNode = opNode.Previous;
LinkedListNode <object> rightNode = opNode.Next;
Expression left = (Expression)leftNode.Value;
Expression right = (Expression)rightNode?.Value;
OperatorCall result = new OperatorCall(token, left, right);
items.AddBefore(leftNode, result);
items.Remove(leftNode);
items.Remove(opNode);
if (rightNode != null)
{
items.Remove(rightNode);
}
}
LinkedListNode <object> current, next;
foreach (Operator[] group in Operator.OperatorPrecedenceGroups)
{
current = items.First.Next;
while (current != null)
{
next = current.Next?.Next;
Token token = (Token)current.Value;
if (Operator.TryParse(out Operator op, text:token.Content))
{
if (group.Contains(op))
{
ParseOperatorToken(current);
}
}
current = next;
}
}
current = items.First.Next;
while (current != null)
{
ParseOperatorToken(current);
current = current.Next?.Next;
}
if (items.First.Next != null)
{
throw new Exception("Unable to parse all operators");
}
return((Expression)items.First.Value);
}