copy-symbol

ToC

Allegro CL

ANSI Common Lisp

10 Symbols

10.2 Dictionary of Symbols

10.2.6 copy-symbol

Function

Syntax:

copy-symbol symbol &optional copy-properties

new-symbol

Arguments and Values:

symbol - a symbol.

copy-properties - a generalized boolean. The default is false.

new-symbol - a fresh, uninterned symbol.

Description:

copy-symbol returns a fresh, uninterned symbol, the name of which is string= to and possibly the same as the name of the given symbol.

If copy-properties is false, the new-symbol is neither bound nor fbound and has a null property list. If copy-properties is true, then the initial value of new-symbol is the value of symbol, the initial function definition of new-symbol is the functional value of symbol, and the property list of new-symbol is a copy₂ of the property list of symbol.

Examples:

 (setq fred 'fred-smith)   FRED-SMITH
 (setf (symbol-value fred) 3)  3
 (setq fred-clone-1a (copy-symbol fred nil))  #:FRED-SMITH
 (setq fred-clone-1b (copy-symbol fred nil))  #:FRED-SMITH
 (setq fred-clone-2a (copy-symbol fred t))    #:FRED-SMITH
 (setq fred-clone-2b (copy-symbol fred t))    #:FRED-SMITH
 (eq fred fred-clone-1a)  false
 (eq fred-clone-1a fred-clone-1b)  false
 (eq fred-clone-2a fred-clone-2b)  false
 (eq fred-clone-1a fred-clone-2a)  false
 (symbol-value fred)  3
 (boundp fred-clone-1a)  false
 (symbol-value fred-clone-2a)  3
 (setf (symbol-value fred-clone-2a) 4)  4
 (symbol-value fred)  3
 (symbol-value fred-clone-2a)  4
 (symbol-value fred-clone-2b)  3
 (boundp fred-clone-1a)  false
 (setf (symbol-function fred) #'(lambda (x) x))  #<FUNCTION anonymous>
 (fboundp fred)  true
 (fboundp fred-clone-1a)  false
 (fboundp fred-clone-2a)  false

Exceptional Situations:

Should signal an error of type type-error if symbol is not a symbol.

See Also:

make-symbol

Notes:

Implementors are encouraged not to copy the string which is the symbol's name unnecessarily. Unless there is a good reason to do so, the normal implementation strategy is for the new-symbol's name to be identical to the given symbol's name.

Allegro CL Implementation Details:

None.