Not necessarily. Some Prolog implementations have module/packaging systems, some don't. Prolog is a weird language - many details feel very antiquated* , yet on the whole it's way ahead of its time (esp. constraint programming). I think it would fare much better as an embedded library (like e.g. Lua or SQLite), rather than a freestanding language. Working on it, though I will likely finish other projects first.
* Case in point: Loading a file is "consult"; I assume this is historically because Prolog was originally a language for doing NLP in French. (See e.g. HoPL-2.)
* Case in point: Loading a file is "consult"; I assume this is historically because Prolog was originally a language for doing NLP in French. (See e.g. HoPL-2.)