What is SETQ in Elisp?
(setq var1 form1 var2 form2 …) is the simple variable assignment statement of Lisp. First form1 is evaluated and the result is stored in the variable var1, then form2 is evaluated and the result stored in var2, and so forth. setq may be used for assignment of both lexical and dynamic variables.
What is Defvar Lisp?
In Emacs Lisp, a variable such as the kill-ring is created and given an initial value by using the defvar special form. The name comes from “define variable”. The defvar special form is similar to setq in that it sets the value of a variable.
What is SETQ in Emacs?
‘setq’ does not evaluate SYMBOL; it sets the symbol that you write. Since it is a function rather than a special form, the expression written for SYMBOL is evaluated to obtain the symbol to set. This is useful if you have stored the actual symbol to be set, say SYM , in a variable, say VAR . Then you use.
What does progn do in Lisp?
Description: progn evaluates forms, in the order in which they are given. The values of each form but the last are discarded. If progn appears as a top level form, then all forms within that progn are considered by the compiler to be top level forms.
What is the difference between Setf and SETQ?
What is the difference between setf and setq? Explanation: Setq is used only for setting the values of symbols but setf can be used for anything. Explanation: Setq is used only for symbols and setf is used for any data type, so Setf can be used in place of setq but setq cannot be used in place of setf.
What does cons mean in Lisp?
cons constructs memory objects which hold two values or pointers to values. These objects are referred to as (cons) cells, conses, non-atomic s-expressions (“NATSes”), or (cons) pairs. In Lisp jargon, the expression “to cons x onto y” means to construct a new object with (cons x y) .
How are variables defined in LISP?
Since there is no type declaration for variables in LISP, you directly specify a value for a symbol with the setq construct.
What does SETQ stand for?
quoted
The ‘ q ‘ in setq stands for “quoted”. The value of the setq form is the value of the last form . (setq x (1+ 2)) ⇒ 3 x ; x now has a global value. ⇒ 3 (let ((x 5)) (setq x 6) ; The local binding of x is set.
What is Cond LISP?
COND. COND is an unusual function which may take any arbitrary number of arguments. Each argument is called a clause, and consists of a list of exactly two S-expressions. We will call the first S-expression in a clause a condition, and the second S-expression a result.
What is Setf in Lisp?
setf is actually a macro that examines an access form and produces a call to the corresponding update function. Given the existence of setf in Common Lisp, it is not necessary to have setq, rplaca, and set; they are redundant. They are retained in Common Lisp because of their historical importance in Lisp.
What is the value of Q after this statement?( Setf Q 14?
What is the value of q after this statement? Explanation: Setf will give the value 2 to q. And q being a variable stores the value in it. And hence it’s value becomes 2.