qc-0.1.0 is not a library.
Quick Calc
SPACE
ABCDEFGHIJKLMNOPQRSTUVWXYZ
abcdefghijklmnopqrstuvwxyz
0123456789
@[]^_{}+,-./:
Dangerous:
\`|~<>"'#&()*;? TAB
Questionable:
{}!%=
~ - can use if not first character in a line
$ - on its own can be an operator, but not in fish
% - used for job control than zsh
= _ zsh ? is not ok