[racket-dev] Transparent Structures in XML Library

What you need is a way to override certain aspects of a transparent struct's behavior, e.g., printing. -- Matthias



On Oct 3, 2011, at 6:17 PM, Doug Williams wrote:

> The main problem I see with transparent structures is that they are also inherently mutable. Some of the operation provided may well make use of that - for example removing whitespace. And, internally, it may be that the structures are created and then filled - as opposed to building the substructures and then creating the structure. I really haven't looked.
> 
> But, in a larger sense, it is what it is. The API provides transparent structures and there may be code that relies on it. I may even rely on it somewhere. So, leaving then as transparent is probably the best way to go - with prop:custom-write properties to limit the resulting print consequence.
> 
> Rewriting it could always be Neil T's next project. :)
> 
> Doug
> 
> On Mon, Oct 3, 2011 at 4:06 PM, John Clements <clements at brinckerhoff.org> wrote:
> 
> On Oct 3, 2011, at 3:01 PM, Doug Williams wrote:
> 
> > The fact that transparent structures also print all of their element - in this case recursively, ad nauseam - is more of a side effect. In that case, I think prop:custom-write properties should be added. I assume any of the print limiting options in my case still walk the entire structure and create a several tens of megabytes long string just to truncate it.
> 
> I see. I misread your first mail as suggesting that the XML structures should not be #:transparent.
> 
> John
> 
> 
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