Hi Offray,

The chapter about Roassal contains several examples on how to name nodes:

To label the nodes, the simplest way is to use @ RTLabelled. (However, you need first to add the element in the view before doing @ RTLabelled). This works pretty well. Here is your code:

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"Definimo los elementos, que denominamos simplemente e1, e2, etc, con
su color y su tamaño"
e1 := (RTEllipse new color: (Color blue alpha: 0.4); size: 20) elementOn: 'hello'.
e2 := (RTEllipse new color: (Color red alpha: 0.4); size: 20) elementOn: 'Bonjour'.
e3 := (RTEllipse new color: (Color yellow alpha: 0.4); size: 20) elementOn: 'Gutten Tag'.
e4 := (RTEllipse new color: (Color green alpha: 0.4); size: 20) elementOn: 'BuenGiorno'.

"Adicionamos los elementos a la vista"
vista add: e1; add: e2; add: e3; add: e4.

"Decimos que los elementos antes definidos se podrán arrastrar"
e1 @ RTDraggable @ RTLabelled.
e2 @ RTDraggable @ RTLabelled.
e3 @ RTDraggable @ RTLabelled.
e4 @ RTDraggable @ RTLabelled.

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You have something like that: 

For the edges, you can simply use @RTLabelled on an edge.

Consider:

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line1 := line edgeFrom: e1 to: e2.
line2 := line edgeFrom: e2 to: e1.
line3 := line edgeFrom: e1 to: e2.
line4 := line edgeFrom: e2 to: e2.
line5 := line edgeFrom: e3 to: e4.
vista add: line1.
vista add: line2.
vista add: line3.
vista add: line4.
vista add: line5.

line1 @ RTLabelled.
line2 @ RTLabelled.
line3 @ RTLabelled.
line4 @ RTLabelled.
line5 @ RTLabelled.

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You can particularize the edge label with something like: line1 @ (RTLabelled new text: 'my edge').

Cheers,

Alexandre