在认证 ACL2 书籍时,我经常收到以下错误消息:
| ACL2 Error in ( INCLUDE-BOOK "something" ...): The ttag :FAST-CAT
| associated with file /elided/acl2/books/std/string\
| s/fast-cat.lisp is not among the set of ttags permitted in the current
| context, specified as follows:
| NIL.
| See :DOC defttag.
怎么了?