[reikonomusha]

Which of course, we shall remember comes from our beloved Scheme. :)

[cutler]

.... and Perl and Smalltalk, the latter arguably being the greater influence.

[masklinn]

Smalltalk did not have the ?/! delineation that GP is specifically talking about. Not that Ruby used it consistently (it was largely just for enumerators e.g. Array#push rather than Array#push!).