[Haskell] HaXml

[Dominic Steinitz]

I'd be grateful for some help on using HaXml.

1. I can parse a String into a Document but it's not clear how you operate on 
it as the combinators all operate on Content. The only function I could find 
that operated on a Document was "document" in Pretty.

2. I can construct a CFilter but it's not clear how you operate on it. How do 
I calculate the number of components of an Element? What I would like to do 
is accept "vname" (with 3 elements) and reject "iname" (with 4 elements). I'd 
also like to check that the characters in givenName, initial and familyName 
are in a given range (for example upper case or between ' ' and '~').

Thanks, Dominic.

import Text.XML.HaXml
import Text.XML.HaXml.Pretty

xmlName =
   "<Name><givenName>John</givenName>" ++
         "<initial>P</initial>" ++
         "<familyName>Smith</familyName>" ++
   "</Name>"

d = document $ xmlParse "tmp" xmlName

gn = mkElemAttr "givenName" [] [literal "John"]
i  = mkElemAttr "initial" [] [literal "P"]
fn = mkElemAttr "familyName" [] [literal "Smith"]

validName = mkElemAttr "Name" [] [gn,i,fn]
invalidName = mkElemAttr "Name" [] [gn,i,i,fn]

vname = processXmlWith validName
iname = processXmlWith invalidName

*Main> d
<Name
  ><givenName
    >John</givenName
  ><initial
    >P</initial
  ><familyName
    >Smith</familyName></Name>
*Main>

*Main> vname
<?xml version='1.0'?>
<Name
  ><givenName
    >John</givenName
  ><initial
    >P</initial
  ><familyName
    >Smith</familyName></Name>
*Main>