Re: XML as a transition to s-expr

[address@hidden]

Lauri Alanko <la@iki.fi> writes:

> On Tue, Dec 18, 2001 at 11:38:47AM -0500, Scott McKay wrote:
> > You have over-simplified here, by cramming together two different
> > concepts: "attributes" and "bodies".
> 
> If that is the case, then you also have crammed together two different
> concepts: "attribute names" and "attribute values". A plist is also a
> user-friendly simplification of an alist. If you want a "clean" syntax,
> wouldn't you prefer the one used by PLT Scheme's XML package:
> 
> (table ((cellpadding "0") (cellspacing "0"))
>  (tr ()
>   (td ((width "50%"))
>     "Cell one")
>   (td ((width "50%"))
>     "Cell two")))
> 
> Still more verbose, but "purer".

When I was writing a markup language embedded in scheme (yes, this is
the second project everyone does after writing their own web server in
scheme), I found that the originally suggest syntax:

((table :cellpadding 0 :cellspacing 0)
  ((tr)
   ((td :width "50%") "Cell one")
   ((td :width "50%") "Cell two")))

had much to recommend it.  The biggest advantage is that the tags
still make sense when they stand alone.  For instance, you can write: 

((table :cellpadding 0 :cellspacing 0)
  ((tr)
   (map (td :align "right") 
        '("Cell one" "Cell two" "Cell three"))))


Now admittedly you can read and parse any sort of parenthesized
expression into something useful, but I was able to avoid writing a
parser and evaluator and I got higher-order tags out of it to boot.