2021年8月10日(火) 4:10 Lassi Kortela <xxxxxx@lassi.io>:

I too strongly prefer the prefix : for uniformity with other Lisp
dialects. At least CL, Emacs Lisp, Clojure, and Hy all have it. Lisp is
also a prefix language, so a prefix syntax is consistent with the rest.

Scheme consistently uses suffixes to indicate semantic information - question mark for predicates, exclamation mark for mutation, and colon for keyword usage.

-- 

Alex