[Adobe-source-devel] Re: asl-users: reverse fullorder for forest -

[Sean P. <sp...@ad...>]

On Dec 13, 2005, at 10:10 AM, Foster T. Brereton wrote:

> Just a couple comments at this point...
>
> On Dec 12, 2005, at 04:57p, Sean Parent wrote:
>
>> One option is to nuke the reverse fullorder iterator (Eric?) - you  
>> could still use a general reverse iterator adaptor, but you would  
>> lose the ability to toggle edges which in reverse is a  
>> questionable thing to do (it base iterator does a very odd flip  
>> around the pointed to node).
>
> What's the difference between a cursor and an iterator?

Well - generally a cursor is a more general form of an iterator - I  
go back and forth with Forest between wanting to call it a fullorder  
iterator and fullorder cursor - it meets the requirements of an  
iterator, but I find it odd to have an iterator which visits every  
node twice.... I might just stick with iterator though and pull the  
cursor terminology.

>
>> Another thing I somewhat dislike is the use of a bool (maybe it  
>> should be called edge and return an enum?) -
>>
>> if (i.edge() == adobe::forest_leading_s)...
>>
>> I like the idea but dealing with enum types is just plain  
>> cumbersome...
>
> adobe/future/enum_ops.hpp may help out with enumeration  
> manipulation. I like the idea of being more explicit about the edge  
> the iterator is on. It makes the code easier to read, and can lend  
> itself to better generalization IMO (see below).
>
>> Another option that I'm somewhat fond of is to simply use  
>> leading_of and trailing_of as stand alone functions - then maybe  
>> have an is_leading and is_trailing for completeness-
>>
>> <snip>
>>
>> is_edge<adobe::forest_leading_s>(i);
>> i = edge<adobe::forest_trailing_s>(i);
>
> This to me would be a natural extension of using the enumerations  
> above -- I like it. Wouldn't it also allow for the consolidation of  
> preorder_iterator and postorder_iterator into some  
> order_iterator<Enum>(), where the while statement is simply while (! 
> this->base().edge() == Enum) ? There could be more consolidation  
> than even this, but it was the first one that I saw.

A good observation - thanks,
Sean

>
> Blessings,
> Foster
>
>
> --
> Foster T. Brereton              <}}}><              Romans 3:21-26
> A d o b e   S o f t w a r e   T e c h n o l o g y   L a b
> "The fact is that the author of STL does not know how to write min,  
> the author of C++ is not quite sure, and the standards committee is  
> at a loss." -- Alexander Stepanov
>
>