MarcXmlEncoder ouputs "leader" wrongly

[dr0i]

Reported by @hagbeck, this ouput is wrong:

<marc:controlfield tag="type"></marc:controlfield>
<marc:controlfield tag="leader">00424nam a2200024 c 4500</marc:controlfield>

It's produced opening a MarcXml file, using the following flux:

sourceFile|
open-file|
decode-xml|
handle-marcxml|
morph(morphFile, *)|
encode-marcxml|
write(targetFile);

with this simple '_elseNested' morph:

<?xml version="1.0" encoding="UTF-8"?>
<metamorph xmlns="http://www.culturegraph.org/metamorph"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1" entityMarker=".">
    <rules>
        <data source="_elseNested" />
    </rules>
</metamorph>

@hagbeck : do you know how exactly: the output should look like?

Results from #107.

[hagbeck]

I'm expecting it like

    <marc:record type="...">
        <marc:leader>00424nam a2200024 c 4500</mx:leader>

respectively

    <marc:record>
        <marc:leader>00424nam a2200024 c 4500</mx:leader>

if type is empty or Null.

I've observed another effect.

<marc:datafield tag="856" ind1="4" ind2="0">
   <marc:subfield code="u">http://www.video2brain.com/</mx:subfield>
   <marc:subfield code="x">Agentur</mx:subfield>
</marc:datafield>

results in multiple entities like

<marc:datafield tag="856" ind1="4" ind2="0">
        <marc:subfield code="u">http://www.video2brain.com/</marc:subfield>
</marc:datafield>
<marc:datafield tag="856" ind1="4" ind2="0">
        <marc:subfield code="x">Agentur</marc:subfield>
</marc:datafield>

using the above morph.

[blackwinter]

This issue seems to be threefold:

1. Entity with more than one subfield results in multiple entities; see _elseNested: Entity with more than one subfield results in multiple entities #338.
2. XML attributes are transformed into elements; see XML Attributes and Element values #379.
3. MARC leader results in control field (<marc:controlfield tag="leader"> instead of <marc:leader>).

Part 1 is already solved and part 2 is covered by another issue; so I would propose to only deal with part 3 here (and update the title accordingly).