The @<guard-form> is evaluated, and then the @<form>s are evaluated in
sequence within a pretty-printer logical block writing to the stream named
by the symbol @<stream-var>. If the @<guard-form> evaluates to nil, then
The @<guard-form> is evaluated, and then the @<form>s are evaluated in
sequence within a pretty-printer logical block writing to the stream named
by the symbol @<stream-var>. If the @<guard-form> evaluates to nil, then