For this standard, some features from the language described in Common Lisp: The Language have been removed, and others have been deprecated (and will most likely not appear in future Common Lisp standards). Which features were removed and which were deprecated was decided on a case-by-case basis by the X3J13 committee.
Conforming implementations that wish to retain any removed features for compatibility must assure that such compatibility does not interfere with the correct function of conforming programs. For example, symbols corresponding to the names of removed functions may not appear in the the COMMON-LISP package. (Note, however, that this specification has been devised in such a way that there can be a package named
LISP which can contain such symbols.)
Conforming implementations must implement all deprecated features. For a list of deprecated features, see Section 1.8 (Deprecated Language Features).
string-char was removed.
commonp were removed.
The special operator
compiler-let was removed.
The font argument to digit-char was removed. The bits and font arguments to code-char were removed.
*break-on-warnings* were removed.
#,” reader macro in standard syntax was removed.
The packages LISP, USER, and SYSTEM are no longer required. It is valid for packages with one or more of these names to be provided by a conforming implementation as extensions.