In the specific case where I want the ternary operator to give me an operator, it fails, but the if then else approach works. I expect there is an explanation, or maybe it is a bug.
What does not work
julia> a = "1+2"; julia> op = contains(a, '+') ? + : - ERROR: syntax: whitespace not allowed after ":" used for quoting Stacktrace:  top-level scope @ none:1
and what does work
julia> a = "1+2"; julia> if contains(a, '+') op = + else op = - end + (generic function with 206 methods) julia> op(4,5) 9