Do Explorative Programming in tclsh with Readline Support

[Ryan Schmidt]

I'm trying to follow these instructions for the first time and am not  
having any luck, so I don't know if I'm doing something wrong or if  
the instructions need to be changed e.g. for MacPorts 1.8.0 or if  
there is a bug in MacPorts 1.8.0.

http://trac.macports.org/wiki/CommittersTipsAndTricks#DoExplorativeProgrammingintclshwithReadlineSupport

I have created the file macports_testing.tcl with the specified  
contents (except that on the first line I use "/opt/local/Library/Tcl"  
etc. because that is where my macports1.0 lives).

Leaving rlwrap out of it for the moment, I can run "tclsh" (or  
"tclsh8.4" or "tclsh8.5"). But as soon as I try to "source ~/path/to/ 
macports_testing.tcl" I don't see the successful "1.0" message but  
instead:

can't read "workpath": can't read "portbuildpath": no such variable

Can anybody help?