override—a generalized boolean; evaluated.
The default is nil.
forms—an implicit progn.
results—the values returned by the forms.
Executes forms from left to right.
Within the dynamic environment of with-compilation-unit,
actions deferred by the compiler until the end of compilation will be
deferred until the end of the outermost call to with-compilation-unit.
The set of options permitted may be extended by the implementation, but the only standardized keyword is :override.
If nested dynamically only the outer call to
with-compilation-unit has any effect unless the value
associated with :override is true, in which case warnings are
deferred only to the end of the innermost call for which override is true.
The function compile-file
provides the effect of
(with-compilation-unit (:override nil) ...)
around its code.
Any implementation-dependent extensions can only be provided as the result of an explicit programmer request by use of an implementation-dependent keyword. Implementations are forbidden from attaching additional meaning to a use of this macro which involves either no keywords or just the keyword :override.
If an implementation would normally defer certain kinds of warnings, such as warnings about undefined functions, to the end of a compilation unit (such as a file), the following example shows how to cause those warnings to be deferred to the end of the compilation of several files.
(defun compile-files (&rest files)
(with-compilation-unit ()
(mapcar #'(lambda (file) (compile-file file)) files)))
(compile-files "A" "B" "C")
Note however that if the implementation does not normally defer any warnings, use of with-compilation-unit might not have any effect.