RE: mapping (Was: Re: [xsl] Re: . in for)

[DPawson at rnib dot org dot uk]

Hi Jeni.
> > +1 on mapping, but I dislike the above syntax Jeni.
> > Scheme gives (map fn sequence).
> >
> > How about 
> >
> > select='map lower-case(.) $departments'/>
> > or
> > select='map (lower-case(.) $departments)'/>
> >
> > or does this go against the idea of extending keywords?
> 
> Well, neither follows the pattern of other operators/keywords in the
> XPath 2.0 WD (in particular the second will get confusing because it
> looks like a function but without a comma between the arguments) 

Yes, I suppose to follow a standard function form it should be

select ='map (lower-case(), $departments)'.
(Accepting Dimitre's comment too).



> but this organisation doesn't make it particularly easy to pipe
> functions together (or at least not in a similar way to location
> paths).

I'm sure David C or Dimitre could extend this to a piped form?
Guessing,
  select='map (fnA(), (map (fnb(), $departments)))'

which maps function A over the result set of mapping function b
over $departments?

Like this more and more!


 Using the example:
> 
>   $coordinates -> (. * 2)
>                -> if (position() mod 2) then . + 50 else .
> 
> I think that the above syntax would be:
> 
>   map (if (position() mod 2) then . + 50 else .) over
>   map (. * 2) over $departments

How about map (plus50-if-odd(), .)

then the function would check for position and do the 
adding 50 if applicable?


> If you want keywords, we could keep the for expression, just drop the
> range variable, so that you had:
> 
>   for $departments return lower-case(.)

Having got used to xml syntax, the for in the xpath bit
strikes me as really out of place, I don't like it at all.
IMHO it should be brought back into xml syntax.

Regards DaveP

******** snip here **************

- 

NOTICE: The information contained in this email and any attachments is 
confidential and may be legally privileged. If you are not the 
intended recipient you are hereby notified that you must not use, 
disclose, distribute, copy, print or rely on this email's content. If 
you are not the intended recipient, please notify the sender 
immediately and then delete the email and any attachments from your 
system.

RNIB has made strenuous efforts to ensure that emails and any 
attachments generated by its staff are free from viruses. However, it 
cannot accept any responsibility for any viruses which are 
transmitted. We therefore recommend you scan all attachments.

Please note that the statements and views expressed in this email 
and any attachments are those of the author and do not necessarily 
represent those of RNIB.

RNIB Registered Charity Number: 226227

Website: http://www.rnib.org.uk 


 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list