Hello Ricardo,

> > 	https://reposcope.com/man/en/3guile/gv  

> Yes, graphviz comes with Guile bindings.  Since they don’t provide a
> Guile module you need to define a module like this:

> --8<---------------cut here---------------start------------->8---
> (define-module (libgv)
>   #:export (digraph node edge layout render setv))
> 
> (load-extension "libgv_guile" "SWIG_init")
> --8<---------------cut here---------------end--------------->8---

Right, but the module I was looking at - but did not try - exports quite
a lot more functionality ...

	https://github.com/roelj/graphviz-guile/blob/master/graphviz.scm

David