> The obvious use case is reading, altering AND writing back
That’s actually (if what you are reading is human-edited input thar you might transform but expect to be human edited) a hard case, because then you want to keep as much as possible the format entered in, while accommodating changes, which is easy to subjectively evaluate but seems potebtially hard to express mechanically in a way which would provide generally optimal UX. You don’t want to hand edit config and have a UI, but have an “I touched it with the UI and made a couple small changes out of dozens of entries and now its unrecognizable”.
That’s actually (if what you are reading is human-edited input thar you might transform but expect to be human edited) a hard case, because then you want to keep as much as possible the format entered in, while accommodating changes, which is easy to subjectively evaluate but seems potebtially hard to express mechanically in a way which would provide generally optimal UX. You don’t want to hand edit config and have a UI, but have an “I touched it with the UI and made a couple small changes out of dozens of entries and now its unrecognizable”.