XML and table interpretation

[Johannes Graumann <johannes_graumann@web.de>]

Why do these two things work:

1)\defineXMLnested
  [td]
  [rows=1,cols=1]
  {\bTD[nr=\XMLop{rows},nc=\XMLop{cols}]}
  {\eTD}
(in conjunction with '<tr><td rows="2">Gene product</td><td cols="3">HPM
tag</td><td rows="2">TAP tag</td><td rows="2">mod. TAP tag</td><td
rows="2">Frequ. in ref. set</td></tr>')


2) \bTR[bottomframe=on,rulethickness=0.3pt]\bTD a \eTD\bTD b \eTD\bTD b
\eTD\bTD c \eTD\eTR%

But this doesn't?

\defineXMLnested 
  [tr]
  [bottomframe=off,rulethickness=0.3pt]
 {\bTR[bottomframe=\XMLop{bottomframe},rulethickness=\XMLop{rulethickness}]}
  {\eTR}

together with '<tr bottomframe="on"><td rows="2">Gene product</td><td
cols="3">HPM tag</td><td rows="2">TAP tag</td><td rows="2">mod. TAP
tag</td><td rows="2">Frequ. in ref. set</td></tr>'

Thanks, Joh