Macro: (aps x) : Returns a list of all bound Arc symbols for which x (coerced to a string) is a substring of the symbol (coerced to a string). Come to think of it, I'll make it sort them, too. Extremely useful if you wonder what precisely a function was named, or whether certain functions exist.
Implementing this requires access to the underlying Racket (or something similar in non-Racket Arc implementations). If, as in Anarki, ($ expr) causes expr to pass straight through the Arc compiler into underlying Racket, then the following implementation will work: