Which expressions are evaluated during compilation only, which are written to the file to
be evaluated at load time, and which do both can be controlled by the EVAL and
IGNORE properties of function names. In addition, the following functions may also be
used.
(commentoutcode U:form): nil macro
Comment out a single expression.
(compiletime U:form): nil expr
Evaluate the expression U at compile time only.
(bothtimes U:form): U:form expr
Evaluate the expression U at both compile time and load time.
(loadtime U:form): U:form expr
Evaluate the expression at load time only.