rougail-output-doc/tests/docs/no_namespace/00_9default_calculation_param_optional.sh

# dictionaries/rougail/00-base.yml

```yaml
---
version: '1.1'
var1:
  description: a first variable
  default:
    jinja: '{% if var2 is defined %} {{ var2 }} {% elif var3 is defined %} {{ var3
      }} {% elif var4 is defined %} {{ var4 }} {% else %} {{ _.var2 }} {% endif %} '
    params:
      var2:
        variable: _.var2
        optional: true
      var3:
        variable: _.var3
        optional: true
      var4:
        variable: _.unknown_family.var
        optional: true
    description: returns a value
  mandatory: false
var2: no    # a second variable
```
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┃                                                                                                                 Variables                                                                                                                  ┃
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  Variable                           Description                       
 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 
  var1                                                                 
  string standard                    A first variable.                 
  Default: returns a value.                                            
  var2                                                                 
  string standard mandatory          A second variable.                
  Default: no