PlantUML - Long description with nest brackets

Question

I'm trying to draw a long description square with nested components.

Something like

node mynode [
<<device>>
--
long description here
] {
    artifact "a nested element"
}

The processor give me error until I remove the long description bracket (or viceversa, I decide to remove the nested element). Therefore, if both elements are presents, some problems occurs.

Answer 1

How about this:

@startuml
node "<<device>>\n----\nlong description here" as mynode {

artifact "a nested element"
}
@enduml

Answer 2

If simple text long description is enough, then you can just put description in quotation marks and use alias:

database "Some long description" as oracle1 {
  storage data
}
actor user 
user --> oracle1

If more complex description is required then you can use nested diagrams. But in this case you can't link elements of nested diagrams with elements of the outer diagram.

rectangle rect1 [
Long long description
---
Some more
===
{{
  rectangle nested1
  rectangle nested2
  nested1 --> nested2
}}
]
rectangle rect2

rect1 ---> rect2