%YAML 1.2
---
version: 1.1

condition: false  # a condition

var1:
  description: a first variable
  mandatory: false
  hidden:
    variable: _.unknown
    optional: true

var2:
  description: a first variable
  mandatory: false
  hidden:
    variable: _.unknown
    optional: true
    default: true

var3:
  description: a second variable
  mandatory: false
  hidden:
    variable: _.condition
    optional: true
    default: true

var4:
  description: a forth variable
  mandatory: false
  hidden:
    variable: _.condition
    optional: true
    default: false
...