xcode user script - Apple Script - Sort selected lines by length

Question

I need to create a user scripts in xcode where I can sort a selection of multiple lines, by their length (number of characters)

I know of this macro variable PBXTextLength, but not sure how to write the script.

this is the sort selection script in Xcode:

echo -n "%%%{PBXSelection}%%%"
sort <&0
echo -n "%%%{PBXSelection}%%%"

how can i modify that script to sort the selection by the length of the line (PBXTextLength)?

thanks