This is really interesting. The case pointed out in Ex.3 is pretty hilarious:
(from the bash manual)
The ERR trap [same rules as set -e] is not executed if the
failed command is part of the command list immediately following
a while or until keyword, part of the test in an if statement,
part of a command executed in a && or || list except the command
following the final && or || [...]
I like cabal because I can read & write messages when I'm offline or there's no internet. It's also nice because I can start a private chat room for my friends without anyone needing to host and maintain any servers or infrastructure.
If you want the best Web App in the world take my codebase (quanta.wiki) and built on top of it. The whole thing is a simple tree structure, on MongoDB, using a 'path-based' tree so you don't even have to learn a specific relational database structuring, and you can put something else on the back end to replace MongoDB. If you like Java+TypeScript+React then I've given you a 250,000 loc head start.
The User Guide and screencasts only show about 10% of the functionality, so you really don't have any way to judge it, but you can still guess can't you.
(from the bash manual)