Yes, GSL is the successor. It's a living project on github. It is relatively easy to generate state machines in GSL, e.g. https://github.com/CodeJockey/glar150/blob/master/src/fsm_c..... This GSL script builds a FSM that uses switch statements; the code isn't as compact as Libero produces yet it works nicely.
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Oops -- these end-points are dead too :) Back to the scavenger hunt.
q: Is there a logical successor to libero? A few of my searches took me to references to GSL...
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https://github.com/imatix-legacy