error-handling - 可以使用make-instance创建条件吗？

Question

在Common Lisp中，使用make-instance而不是make-condition制作条件对象是否可移植？
例如:

(define-condition foo (condition)
  ())

(make-condition 'foo)
(make-instance 'foo)

这与在CLOS类层次结构中放置条件的方式有关吗？ (subtypep 'condition 'standard-class)在SBCL和CLISP中返回false。但是， make-instance可以在两个实现中都产生条件。这是由标准保证的吗？

Answer 1

不，这样做显然是不可移植的。从specification:

Conforming code must observe the following restrictions related to conditions:

• define-condition, not defclass, must be used to define new condition types.
• make-condition, not make-instance, must be used to create condition objects explicitly.
• The :report option of define-condition, not defmethod for print-object, must be used to define a condition reporter.
• slot-value, slot-boundp, slot-makunbound, and with-slots must not be used on condition objects. Instead, the appropriate accessor functions (defined by define-condition) should be used