What is the function “defs” in Lisp?

Question

In the "Dictio" file, located at the link "Text-only console version" of this site , I've noticed a Lisp command (?) called defs .

I assume that this is something similar to defun , but am unable to find any information on what defs does; is it used to define a function, or maybe a variable? I am looking to reproduce this code using modern techniques and it would help to know the purpose of defs .

The defs calls seem to also include more than a name before the arguments (I would expect it to read ( defs name () body ).

Looking at the first function in the list, there appears to be more included in this "function definition" [the word 'features' specifically] and in the third function, there is ['semantics'] included after what appears to be the name of the function (before the arguments).

Answer 1

DEFS is defined by the software in the file SYSCOM .

It is a FEXPR , which is a function which gets the arguments unevaluated. Common Lisp has no such feature. It uses macros instead.

Example use:

(DEFS \#COLOR 
    FEXPR (LAMBDA (A)
            (EVAL (SUBST (CAR A)
                         'COLOR
                         '(OBJECT 
                           (MARKERS\: (\#PHYSOB COLOR) 
                                      PROCEDURE\: ((\#COLOR *** COLOR))))))) 
    PRIORITY 192. 
    SYS (\#PROPERTY))

Here you have a symbol #COLOR . It gets a function (actually a FEXPR ) defined under this name. Also it puts a PRIORITY and SYS onto the property list of the symbol. Thus DEFS is used to define symbols with functions and properties in one defining form.