> I'm not completely sold on its contents for the core, however: a lot of
> it looks like a compatibility layer for Clojure's familiarity's sake,
> with very thin wrappers (which basically just add the cost of function
> invocation).
>
> 1. s-prepend/s-append: trivially replaced by 'concat'.


I'd like to get more insights about this point. I think it's a point that
comes back fairly often here, and I'm not sure I fully understand why.

I'll try to explain my side first so you see where I'm coming from. So, I
guess a lot of s.el users think it's a massive improvement over what emacs
has to offer reguarding string manipulations. This is visible in issues
like https://github.com/magnars/s.el/issues/88. I never coded with clojure,
but my argument for these helpers is that in code we do string
manipulations all the time, they are trivial to write, so why not have
trivial helpers. I understand there's a limit to such helpers because you
could write thousands of them, so good taste should be used to introduce
"the minimal set". I usually don't care about these extra function calls,
what matters more to me is how beautiful the code looks and how readable it
is. If performance becomes a concern, then I usually first improve the
algorithm or switch to C++, and only at last measure do I resort to these
"micro optimisations" like avoiding a function call. Because string
manipulation is so trivial, I'd like them to be grouped together so they
are easy to find. In other languages I can usually go to one page and have
the list of all strings related functions. In Emacs the manual at
https://www.gnu.org/software/emacs/manual/html_node/elisp/Strings-and-Characters.html
while
helpful makes it hard to "read it all" and find what you are looking for.
For example I couldn't find concat on that page.

From your side, I understand that your definition of the minimal set is
much thiner, and maybe what would help is to give the complete list of the
functions you find superfluous and why (list at
https://github.com/magnars/s.el so far you mention `s-prepend` and
`s-append`). For example I'd disagree if you said `s-left` and `s-right`
are not useful to import because it can be done with `substring`.

Philippe