See first 25 entries or so in the permuted CL symbol index: http://www.lispworks.com/documentation/lw51/CLHS/Front/X_Perm_P.htm http://www.lispworks.com/docume

See first 25 entries or so in the permuted CL symbol index: http://www.lispworks.com/documentation/lw51/CLHS/Front/X_Perm_P.htm http://www.lispworks.com/documentation/lw51/CLHS/Front/X_Per... Scheme does use ?, and you can in CL if you really want. But CL reserves ? as a programmable reader macro [1]. It is often used, for example, to designate a stand-in domain variable designation in, say an embedded Prolog. Another reason that CL avoids the "?" convention is that it's "unpronounceable" [2]. CL is the only language spec I've seen that discusses pronunciation; they actually gave thought to how programmers might converse about their code unambiguously [3]. Another manifestation of this is CL's sort-of case-insensitivity [4]. -- [1] The other reserved characters are !, [ ], and { } [2] Although at least one wag suggested pronouncing it as "eh?", like a good Canadian. [3] CLtL2 provides quite a bit of this. My fav is a brief excursion into how some hackers pronounce "macrolet" to rhyme with Chevrolet. :) [4] This is not actually the case, but appears to be true to new Lispers, until they understand that by default, the reader converts everything to upcase.