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PDP-10 Maclisp

The ITS Lisp is called Maclisp, or PDP-10 Maclisp if necessary to disambiguate it against Multics Maclisp. Its direct ancestor is PDP-6 LISP.

A sample MACLISP session on ITS using LEDIT MODE in EMACS LEDIT will work on both ITS}} and [[TOPS-20 ;tnx1.0e6 to GLS

KA ITS 1648 DDT 1547 TTY 52 ;System herald

    
    :login smith                              ;The luser logs in
    
    :lisp                                     ;MACLISP is started
    
    LISP 2154                                 ;MACLISP version
    ALLOC? N                                  ;Take the world defaults
    
    (plus 3.14 2.71)                          ;Add two numbers
    5.85
    
    (car '(simple list))                      ;Return the CAR of a LIST
    SIMPLE
    
    (ledit)                                   ;Enters EMACS in LEDIT MODE
    
    (defun sum-squares (a b)                  ;Typed into the EMACS buffer
           (plus (times a a
                 (times b b))))               ;META-Z pushes DEFUN to the world
                                              ;CTRL-X Z returns to LISP
    
    ;READING FROM LEDIT SUN-SQUARES           ;Back in LISP
    ;EDIT COMPLETED
    
    (sum-squares 2.0 3.0)                     ;call SUM-SQUARES
    36.0                                      ;Returns the wrong number
    
    (ledit)                                   ;Re-enter EMACS in LEDIT MODE
    
    CTRL-S (times a a                         ;Typed into EMACS
                                              ;Search for STRING (times a a
    
    (defun sum-squares (a b)                  ;Correct SUM-SQUARES
           (plus (times a a)
                 (times b b)))                ;META-Z pushes new DEFUN to world
                                              ;CTRL-X Z returns to LISP
    
    ;READING FROM LEDIT SUM-SQUARES           ;Back in LISP
    ;EDIT COMPLETED
    
    (sum-squares 2.0 3.0)                     ;Call SUM-SQUARES again
    13.0                                      ;Correct result

The LISP … Editor … LISP … loop will no doubt be repeated many times.