This would be useful and shouldn't be overly complicated to implement. I doubt I have time for that personally in the near future, but if someone else is interested, there ought to be still time to get it into RF 3.1 even.

Would be also handy to be able to use other non-string values. Not sure are custom objects worth the effort, but at least numbers, Booleans, None would be nice. I see two possibilities how to implement that:

• Add a prefix like EVAL__ to mean that the value should be passed through ast.literal_eval. For example, --variable X:EVAL__42. This could be implemented as part of this issue.

• Add support for using variables in the values. This would allow using the built-in variables to specify numbers, Booleans and None like --variable 'X:${42}'. Would also allow other possibly useful usages such as --variable HOST:1.2.3.4 --variable 'URL:http://${HOST}/example'. This would require its own issue.

Issue #2946 proposes adding support for non-string variable values from the CLI. That covers also lists/dicts so let's close this one as its duplicate.