In Toki Pona, the small word o has several meanings.
In the official book Toki Pona: The Language of Good, it says
The particle o has three uses: (1) after a noun phrase to show who is being called or addressed, (2) before a verb to express a command or request, (3) after the subject (and replacing li) to express a wish or desire.
The question is whether a sentence like ”my friend, come here” (using jan pona mi 'my friend', kama 'come', ni 'here') should be jan pona mi o, o kama ni or jan pona mi o kama ni. Or perhaps those phrases are both acceptable? In that case, are they used interchangeably, or are there different use cases or styles?
It seems there are Toki Pona speakers with different opinions on this. Who are they, and what are their arguments?