Last note before I’d like to wrap this up here and move the discussion to Github:
I just released v0.3.0 with support for pluralization! With this release, it should now covers all the gettext features (that I’m aware of - except maybe custom interpolators 
). Feel free to open an issue on GIthub for suggestions or if you encounter any problems.
Thanks a lot for all the feedback and take care! 
Idea: maybe the pluralization does not require any special characters-just use a single string in code and handle pluralization in translations files. This would require another sigil or a modifier to mark a pluralized string.
Not sure I understand. Are you suggesting something like this?
~t"#{count} post(s)"N
msgid "%{count} post(s)"
msgid_plural "%{count} post(s)"
msgstr[0] "One post"
msgstr[1] "%{count} posts"
Hmmm, interesting (assuming you can use the same msgid for singular/plural). I could make the || separator optional (or remove this completely).
What do others think?
That’s a great idea! 
I think I would even get rid of the separator again as this felt a bit hacky from the start. Unless there is a good reason to keep it.
You can even use something like gettext_pseudolocalize | Hex to catch the strings that have missing singular/plural forms.
Interesting concept! 
I think your libaray should work as well while using the sigils.
I really like the proposal regarding pluralization because it allows using gettext progressively without changing the msgid:
# no translation
"#{count} error(s)"
# gettext w/o pluralization
~t"#{count} error(s)"
# gettext with pluralization
~t"#{count} error(s)"N
Granted, you’re still in the situation of having special characters for pluralization that people might want to use in the message:
~t"#{count} child(ren) (other parenthesized text)"N
The message can be anything and there is nothing special about the string in my example.
The proposal is to use the same string for singular and plural msgid. I just chose to use parentesis so the message (and fallback, if there is no translation) works in both cases (something you would do if there wasn’t pluralization).