char-to-octets

Arguments: ef-name char state-loc &key put-next-octet external-format

ef-name should be a symbol. char should be a character. state-loc should be a place suitable as the first argument to setf. put-next-octet should be a form. external-format should be an external-format object or symbol naming an external-format.

The char-to-octets macro expands to the macro stored in the char-to-octets-macro slot of the external-format named by name. See the description of def-char-to-octets-macro for descriptions of the macro's expansion as well as of the get-next-char, put-next-octet, and external-format arguments.

Users generally do not need to invoke the char-to-octets macro. In most cases, it is more convenient to use string-to-octets.

Examples:

;; Ensure utf8 conversion macros are available by explicitly loading the
;; external-format definition.  This suppresses the macro removal
;; optimizations that may occur when external-format is autoloaded.
;;
(let ((*modules* (remove "ef-utf8" *modules* :test #'string-equal)))
  (require "ef-utf8"))

(let ((utf8-vector (make-array 10
			       :element-type '(unsigned-byte 8)
			       :initial-element 255))
      (state nil)
      (str "hello"))
  (do ((s 0 (1+ start-s))
       (start-s 0 s)
       (v 0))
      ((>= s (length str)) utf8-vector)
      ;; :utf8-base is (crlf-base-ef :utf8)
      (char-to-octets :utf8-base (prog1 (schar str s) (incf s)) state
		      :put-next-octet (lambda (b)
					 (setf (aref utf8-vector v) b)
					 (incf v)))))

	   ==> #(104 101 108 108 111 255 255 255 255 255)

See iacl.htm for more information on international character support in Allegro CL.

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This page was not revised from the 10.0 page.
Created 2019.8.20.