[quasigloam]

Although in a Lisp such as Scheme, you could pass around the negation operator in something like (map - '(1 2 3)), so it would be a valid concern that it might clash.

[tmtvl]

The problem with that is that there are spaces between map, -, and '(1 2 3). The only way to get spaces into a name is by using vertical bars:

  (defvar |do i 10| 1.100)