Man: In response to recent demands that Lambdaconf ban an outspoken racist from speaking at our conference...
Man: We've logically proven, using graphs, that to capitulate would violate the property of immutability - a property required by a purely functional conference.
Graphs: a mostly insane set of graphs labelled with things like "Truth", "all species together", "assault", "circular reasoning", "morality is impossible", "psychopath", and "murder"
Man: And the conference must remain pure.
Another man, tied to a chair: Mmf! MMMF!
If you change the output based on external stimulus, you're no better than a LISP.