Generalization of automatic sequences for numeration systems on a regular language

Let L be an infinite regular language on a totally ordered alphabet (Σ,<). Feeding a finite deterministic automaton (with output) with the words of L, enumerated lexicographically with respect to <, leads to an infinite sequence over the output alphabet of the automaton. This process generalizes the concept of k-automatic sequence for abstract numeration systems on a regular language (instead of systems in base k). Here, we study the first properties of these sequences and their relations with numeration systems.