[Elixir][Erlang]difference of binary

double quote and single quote have different meanings between Elixir and Erlang. In addition, “$” and “?” also have.

They make me confuse a bit … 😦

> ?a
97

> [?a] == 'a'
true
> [?a] == "a"
false

> is_bitstring "a"
true
> is_bitstring 'a'
false

> $a.
97

> [$a] == "a".
true
> [$a] == 'a'.
false

> is_bitstring("a").
false
> is_bitstring('a').
false