How to use XElement ?

[PGilbert]

If you define the variable 'myMusic' with the following:

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<Music>
  <Album Title="Chris Sells Live" Artist="Chris Sells" ReleaseDate="2/5/2008" />
  <Album Title="The Road to Redmond" Artist="Luka Abrus" ReleaseDate="4/3/2008" />
  <Album Title="The Best of Jim Hance" Artist="Jim Hance" ReleaseDate="6/2/2008" />
</Music>

and ⎕USING with the following:

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⎕USING←'System.Xml.Linq,System.Xml.Linq.dll'

then you can get an XElement the following way:

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xel←XElement.Parse(⊂myMusic)

the following line is expected to work but cause a DOMAIN ERROR:

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      xel.Elements(⊂'Album')
DOMAIN ERROR
      xel.Elements(⊂'Album')
     ∧

I have tried many things but nothing is working. Is there a way to make this work ?

Thanks in advance,

Pierre Gilbert

[gil]

Hi Pierre

I've never used this before, but testing in v15.0 I got an error message suggesting the syntax for the method call is at fault:

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System.Collections.Generic.IEnumerable`1[System.Xml.Linq.XElement] Elements()
System.Collections.Generic.IEnumerable`1[System.Xml.Linq.XElement] Elements(System.Xml.Linq.XName)

Reading about it on msdn I see that the Elements method requires an instance of the XName class as an argument. XName in turn doesn't have a constructor, but offers a Get method that will return an instance from String. This works for me:

myMusic defined as:

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<Music>
  <Album Title="Chris Sells Live" Artist="Chris Sells" ReleaseDate="2/5/2008">
    <Song Title="Track 1" />
    <Song Title="Track 2" />
    <Song Title="Track 3" />
  </Album>
  <Album Title="The Road to Redmond" Artist="Luka Abrus" ReleaseDate="4/3/2008">
    <Song Title="Track A" />
    <Song Title="Track B" />
    <Song Title="Track C" />
    <Song Title="Track D" />
  </Album>
  <Album Title="The Best of Jim Hance" Artist="Jim Hance" ReleaseDate="6/2/2008">
    <Song Title="Track I" />
    <Song Title="Track II" />
  </Album>
</Music>

I then query the document like this:

      (⌷ xel.Descendants ⍬).Name
 Album  Song  Song  Song  Album  Song  Song  Song  Song  Album  Song  Song 
    (⌷ xel.Elements ⍬).Name
 Album  Album  Album 
   ⍴ ⌷ xel.Elements XName.Get⊂'Song'
0
   ⍴ ⌷ xel.Descendants XName.Get⊂'Song'
9

Merry Christmas!

[PGilbert]

Many Thanks Gil, this has been troubling me for a long time and you found the answer.

Merry Christmas to you to !