5.5. Macro DEFCONSTANT

5.5.1. Variable CUSTOM:*SUPPRESS-SIMILAR-CONSTANT-REDEFINITION-WARNING*

The 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 3.3.3, “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).

Note

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.

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 2.49.60+Last modified: 2017-11-21