Pattern match on any single UTF-8 character - utf-8

Question

I would like to have a function clause that matches any single UTF-8 character.
I can match on specific characters like this
def foo("a") do
"It's an a"
end
But I cannot determine if it possible to do the same for any single UTF8 character.
My current solution is to split the string to a char list and pattern match on that, but I was curious if I could skip that step.

Answer 1

You can do this with:
def char?(<<c::utf8>>), do: true
def char?(_), do: false
Note that this only matches a binary with a single character, to match on the next character in a string, you can just do:
def char?(<<c::utf8, _rest::binary>>), do: true

Answer 2

From the Regex docs:
The modifiers available when creating a Regex are: ...
unicode (u) - enables Unicode specific patterns like \p and changes modifiers like \w, \W, \s and friends to also match on Unicode. It expects valid Unicode strings to be given on match
dotall (s) - causes dot to match newlines and also set newline to anycrlf; the new line setting can be overridden by setting (*CR) or (*LF) or (*CRLF) or (*ANY) according to :re documentation
So you might try:
~r/./us
From http://elixir-lang.org/crash-course.html
In Elixir, the word string means a UTF-8 binary and there is a String module that works on such data
So I think you should be good to go.

Answer 3

TL;DR:
for <<char <- "abc">> do
def foo(unquote(<<char>>)), do: "It's an #{unquote(<<char>>)}"
end
Take a look at https://github.com/elixir-lang/elixir/blob/3eb938a0ba7db5c6cc13d390e6242f66fdc9ef00/lib/elixir/unicode/unicode.ex#L48-L52 You can on compile time generate function for each character in binary ("abc" in my example). It's how Elixir unicode support works, check out whole module to better understand.