Proper way to concatenate variable strings in Ansible

Question 1

I need to create new variable from contents of other variables. Currently I’m using something like this:

- command: echo "{{ var1 }}-{{ var2 }}-{{ var3 }}"
  register: newvar

1

2

3

- command: echo "{{ var1 }}-{{ var2 }}-{{ var3 }}"

register: newvar

The problem is:

Usage of {{ var1 }}...{{ varN }} brings too long strings and very ugly code.
Usage of {{ newvar.stdout }} a bit better but confusing.
Usage of set_fact module caches fact between runs. It isn’t appropriate for me.

Is there any other solution?

Question 2

Good question. But I think there is no good answer which fits your criteria. The best I can think of is to use an extra vars file.

A task like this:

- include_vars: concat.yml

1 2	- include_vars: concat.yml

And in concat.yml you have your definition:

newvar: "{{ var1 }}-{{ var2 }}-{{ var3 }}"

1 2	newvar: "{{ var1 }}-{{ var2 }}-{{ var3 }}"

Question: