[ CL means by this "display formatting".]
[Explain what's available in TclDOM and tdom.]
For TclDOM, just use the -indent option. For example,
dom::serialize $dom -indent yes
The man page [L1 ] explains the use of -indent and -indentspec.
[Explain pretty_print package--application, why not at SF, plans, ...] [License, too.] [Last one CL packaged was http://www.phaseit.net/claird/comp.lang.tcl/dom_pretty_print/dom_pretty_print-0.2.tar.Z ]
Also see XML and http://software.decisionsoft.com/software/xmlpp.pl