a generalized boolean.
true.
If it is true, the #.
reader macro has its normal effect.
Otherwise, that reader macro signals an error of type reader-error
.
If *read-eval*
is false and *print-readably*
is true,
any method for print-object
that would output a reference
to the #.
reader macro either outputs something different
or signals an error of type print-not-readable
.