[ANN] XML parser (v0.1)

[Gabor Szokoli]

From: "Denys Duchier" <Denys.Duchier at ps.uni-sb.de>

> Since Gabor just brought up my expat interface, I'll announce a pure
> Oz alternative.

The expat thing is lightning-fast and its external dependency is a
single .dll or .so in runtime, so I'll stick with that.

It may look like a horrible abuse of the delicate XML technology, but
we use it to pass around plain recods of data, and in case anyone else
needs to do only that, here's a little script that might help:
(Should be easy to adopt to the parser package, now it relies on the
parser.oz example of the expat package)

functor
import
   Browser
   X('class' : Parser) at 'Parser.ozf'
define

   %Turns the element into a record.
   % The label is the element type.
   % The features are the attributes and all contained elemet types.
   fun {ParseElement Element}
      {Record.adjoin
       {Parsealist
 {Value.condSelect Element alist nil}
       }
       {ParseContent Element.content {Value.condSelect Element type
root}}

      }
   end

   % Turns the contents of an element into a record.
   % The label is passed at Label.
   % The features are the unique element types.
   % Under each feature there is a list of elements of said type.

   fun {ParseContent Content Label}
      D
   in
      {Dictionary.new D}
      for E in Content do
  %Only elements are considered, everything else is ditched.
  if {Record.is E}
     andthen {Record.label E} == element
  then
     ElementRecord = {ParseElement E}
  in
     %There should be support for this, Dictionary.append or
something.
     {Dictionary.put D {Record.label ElementRecord}
      ElementRecord|{Dictionary.condGet D
       {Record.label ElementRecord} nil
      }
     }
  end
      end
      {Dictionary.toRecord Label D}
   end



   fun {Parsealist AttributeList}
      {List.toRecord attributes
       {List.map AttributeList
 fun {$ Attribute}
    AString = {ByteString.toString Attribute.value}
 in
    %Who needs an XSD? :-))))))
    if {String.isInt AString}
    then
       Attribute.name#{String.toInt AString}
    else
       Attribute.name#{String.toAtom AString}
    end

 end
       }
      }
   end



   P={New Parser initFromFile('noz.xml')}
   {P parse}
   {Browser.object browse({ParseElement P.root})}

end


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