![[CLISP home]](clisp.png){kind=small} | ![[Support CLISP]](http://images.sourceforge.net/images/project-support.jpg){kind=small} |
DEFCONSTANTThe initial value is not evaluated at compile time,
just like with DEFVAR and DEFPARAMETER.
Use EVAL-WHEN if you need the value at compile time.
constant variables may not be bound dynamically or lexically.
See also Section 3.3.2, “Declaration EXT:CONSTANT-NOTINLINE”.
If you need to undo the effects of a DEFCONSTANT form,
PROCLAIM the symbol SPECIAL (to turn the constant variable into a dynamic variable),
and then PROCLAIM it EXT:NOTSPECIAL (to turn the dynamic variable into a lexical variable).
If you follow the usual variable naming convention
(*FOO* for DEFVAR and DEFPARAMETER,
+BAR+ for DEFCONSTANT, ZOT
for LET/LET*), you will save yourself a lot of trouble.
See also Q: A.4.14.
CUSTOM:*SUPPRESS-SIMILAR-CONSTANT-REDEFINITION-WARNING*If the variable being defined by DEFCONSTANT is already bound to
a value which is not EQL to the new value, a WARNING is issued.
If, however, the new value is visually similar
(prints to the same string, as is commonly the case when re-loading files)
to the old one, the warning can be suppressed by setting
CUSTOM:*SUPPRESS-SIMILAR-CONSTANT-REDEFINITION-WARNING* to a non-NIL value.
The initial value of CUSTOM:*SUPPRESS-SIMILAR-CONSTANT-REDEFINITION-WARNING* is NIL.
| These notes document CLISP version 2.49 | Last modified: 2010-07-07 |
| |