tools: stop using string stream
Currently we store everything in strings, including automata passed as file names. This is stupid, as we then turn these strings into stringstreams to parse them... Note that I observed no performance improvements.
We should use streams instead. See https://gitlab.lrde.epita.fr/vcsn/vcsn/tree/ad/tools/streams. The problem is that then we stop guessing the input file format. This is troublesome. We need some rewindable streams for the case of std::cin
.
BTW, this could also simplify the implementation of automaton readers such as efsm
, which works in two-passes: one to guess the type of the automaton (context), then another to build it.