Support sticky punctuation (no whitespace allowed)

[pprindeville]

There are certain structured notational elements that should be represented as an uninterrupted string to reflect their primacy/atomicity.

Examples might be 10.0.0.51:53 or eth0.10.

It would be nice to have a way of bracketing punctuation that signifies that can be no spaces around it.

[olofhagsand]

Cligen works by interspaced keywords and variables (keywords are actual a special case of variables). It is not possible in the current design (or at least very difficult) to violate that.

Examples might be 10.0.0.51:53 or eth0.10

Both your examples are best modelled by variables with a regexp. I am sure you can find examples in som of the standards (https://github.com/YangModels/yang/tree/main/standard) or even vendor specs (https://github.com/YangModels/yang/tree/main/vendor), or openconfig (https://github.com/openconfig/public/tree/master/release/models) or even SNMP-modelled YANG.