DOCBOOK-APPS: two issues with XSLT processors -- xsltproc and xalan

["Robert P. J. Day" <rpjday at mindspring dot com>]

  to follow up bob stayton's recent posting on adding 
<xsl:output indent="yes"> to get indented, hierarchical output:

1) works great with xalan.  xsltproc, on the other hand, doesn't
   seem to recognize this attribute although, in all fairness,
   no XSLT processor is *required* to do so

2) xalan aborts if you don't specify an "-out" option, which 
   certainly disagrees with its command line summary.  if i run
   xalan with the options

   -IN file.xml -XSL file.xsl		# but no -OUT option

   i would have expected to have the result printed to stdout,
   as xsltproc does.

   instead, i get

   (Location of error unknown)XSLT Error 
   (java.lang.IllegalArgumentException): 
   Unknown attribute http://xml.apache.org/xalan/features/incremental

   that came as a bit of a shock.  should i have expected this?

rday