Re: [TED] ACTION-294: Propose a treatment of sequences

an empty list is simply List()
in XML it is
<EnumeratedList/>

By design, there is no such thing as an empty RecursiveList., for the 
same reason that your listconstructor requires at least one element.

Francois Bry (Bry-Haußer) wrote:

>Gary Hallmark wrote:
>  
>
>>I find the pairs really tedious.  How about
>>
>>class LIST
>>   subclass EnumeratedList
>>      property element : TERM*
>>   subclass RecursiveList
>>      property element : TERM+
>>      property rest : TERM
>>    
>>
>Does it mean that a recursive list cannot be empty and that its "rest"
>ist a list term? If yes, this would be strange, I think.
>
>Why not recursive type definitions like:
>
>class LIST
>     emptylist
>     or listconstructor(element LISTITEM, LIST)
>
>with whatever syntax deemed appropriate. My point is that a list
>definition must define both the emptylist and an operator 'list
>constructor' (or however it might be called) with two arguments, a list
>item (or however it might be called) and a list.
>
>Francois
>
>  
>

-- 


Oracle <http://www.oracle.com>
Gary Hallmark | Architect | +1.503.525.8043
Oracle Server Technologies
1211 SW 5th Avenue, Suite 800
Portland, OR 97204

Received on Tuesday, 26 June 2007 17:05:13 UTC