;;; -*- Mode:Lisp; IBase:10.; -*-		Package created by KMP, 11/2/80
;;;
;;; OCTAL: A package for doing shorthand octal input (PDP10 only)
;;;
;;; Sets up "&" as a readmacro to read shorthand octal numbers. (Note that a
;;;  side-effect of this is that &-keywords must be written as /&optional, 
;;;  etc.)
;;;
;;; Style Suggestion:
;;;  This package is not intended for production use (use in programs), since
;;;  it ties down a valuable character, but it can be useful as an interactive
;;;  debugging tool. It is strongly recommended that programs for release use
;;;  the #o octal syntax already which is primitive to Maclisp.
;;;
;;; If a comma (or two) is read in the middle of the number, it divides the
;;;  right and left half of the word being assembled.
;;;
;;; Examples:
;;;
;;;  &77	= 000000,,000077
;;;  &-1,,	= 777777,,000000
;;;  &-1,,1	= 777777,,000001
;;;  &0,,-1	= 000000,,777777
;;;  &,-1	= 000000,,777777
;;;  &37,	= 000037,,000000
;;;
;;; See also the BINPRT package for display of octal numbers.

#-PDP10 (ERROR "This package not written to work except on a PDP10.")

(DECLARE (FIXNUM (READ-OCTAL-AUX) (READ-OCTAL)))

(HERALD OCTAL /3)

(DEFUN READ-OCTAL-AUX ()
  (DO ((I 0. (+ (LSH I 3) (- (TYI) #/0)))
       (S (IF (OR (= (TYIPEEK) #/+) (= (TYIPEEK) #/-))
	      (= (TYI) #/-))))
      ((OR (< (TYIPEEK) #/0) (> (TYIPEEK) #/7))
       (IF (NOT S) I (- I)))
    (DECLARE (FIXNUM I))))

(DEFUN READ-OCTAL ()
  (LET ((TEMP (READ-OCTAL-AUX)))
    (DECLARE (FIXNUM TEMP))
    (COND ((= (TYIPEEK) #/,)
	   (TYI)
	   (IF (= (TYIPEEK) #/,) (TYI))
	   (LOGIOR (LSH TEMP 18.) (LOGAND (READ-OCTAL-AUX) #o777777)))
	  (T TEMP))))

(SSTATUS MACRO /& 'READ-OCTAL)