And if you're really desperate to write infix notation in Lisp, you can use CMU-INFIX [1]: #I( (-b + sqrt(b^^2 - 4*a*c))/(2*a) ) That is completely valid

And if you're really desperate to write infix notation in Lisp, you can use CMU-INFIX [1]: #I( (-b + sqrt(b^^2 - 4*a*c))/(2*a) ) That is completely valid Lisp if you need it. In fact, you can change your editor to highlight #I(...) if you want it to stick out a little more since it's "different" than usual prefix notation. Suffice it to say, a binary expression like (+ b (* m x)) probably doesn't warrant bringing in a library, but if you're calculating orbital dynamics of the solar system, then perhaps having the above library would be useful. [1] https://github.com/quil-lang/cmu-infix https://github.com/quil-lang/cmu-infix