🚀 go-pugleaf

In article <11100002@snail> carroll@snail.CS.UIUC.EDU writes:
>
>	I still don't understand how you would reference a recursive
>data element that was far down in the structure. How would you parametrize
>the reference to, say, the 10th data field of a recursively defined type?
>Would you have to type in 10 "." operators, with the field names
>between them? And how would you handle variable depth references?

If Modula-2 had data type recursion, then roughly like this:
List would be defined by:
	
                  List = RECORD CASE Null:Boolean OF
				   TRUE:              |
				   FALSE: Data:Atom;
					  Next:List
                                END
                         END;

<ACCESING THE TENTH ELEMENT OF THE LIST L:List>

ReadHead is declared to be of type List:

		    ReadHead := L;
		    FOR I := 1 TO 9 DO
			 ReadHead := ReadHead.Next
                    END;
		    RETURN ReadHead.Data;