get-macro-character char &optional readtable ⇒ function, non-terminating-p
set-macro-character char new-function &optional non-terminating-p readtable ⇒ t
| char | a character. |
| non-terminating-p | a generalized boolean. The default is false. |
| readtable | a readtable designator.
The default is the current readtable. |
| function | nil, or a designator for a function of two arguments. |
| new-function | a function designator. |
get-macro-character returns as its primary value, function, the reader macro function associated with char in readtable (if any), or else nil if char is not a macro character in readtable. The secondary value, non-terminating-p, is true if char is a non-terminating macro character; otherwise, it is false.
set-macro-character causes char to be a macro character associated with the reader macro function new-function (or the designator for new-function) in readtable. If non-terminating-p is true, char becomes a non-terminating macro character; otherwise it becomes a terminating macro character.
(get-macro-character #\{) ⇒ NIL, false
(not (get-macro-character #\;)) ⇒ false
The following is a possible definition for the single-quote reader macro in standard syntax:
(defun single-quote-reader (stream char)
(declare (ignore char))
(list 'quote (read stream t nil t))) ⇒ SINGLE-QUOTE-READER
(set-macro-character #\' #'single-quote-reader) ⇒ T
Here single-quote-reader reads an object following the single-quote
and returns a list of quote and that object.
The char argument is ignored.
The following is a possible definition for the semicolon reader macro in standard syntax:
(defun semicolon-reader (stream char)
(declare (ignore char))
;; First swallow the rest of the current input line.
;; End-of-file is acceptable for terminating the comment.
(do () ((char= (read-char stream nil #\Newline t) #\Newline)))
;; Return zero values.
(values)) ⇒ SEMICOLON-READER
(set-macro-character #\; #'semicolon-reader) ⇒ T
The readtable is modified.