Are these constants effectively saving computations?

[juancarlospaco]

Code looks good. You can "unroll" the `if` into a `case`:
    
    
    case c
    of 'A'..'Z': rotateLetter(c, 90, n)
    of 'a'..'z': rotateLetter(c, 122, n)
    else: c
    
    Run

Switching to ROT26 will also save computations.