LISP : Practice Questions and Answers

Atoms are also considered as S-expressions. Rather S-expressions are formed from atoms.

In LISP programming if X and Y are S-expressions then the dotted pair (X.Y) is also considered as S-expression.

Atoms are building blocks of S-expressions. Even atoms are considered as a fundamental unit of LISP.

Yes, all the program statements and data are represented by S-expressions in LISP. S-expressions or symbolic expressions are the syntactic elements of the LISP programming language.

S-expression consists of both Atoms and Lists. It also consists of numeric and literals.

In this 3 times braces () are used. Other possible way is (+ 1 (+ 2 (+ 3 4))) in which again 3 braces () are used.

Yes, the LISP programs can be nested.

Correct syntax of the LISP is ( ...).

Any number of arguments can come in LISP single program. As an example, the addition (+) primitive takes any number of arguments.

Argument is a part of basic syntax of LISP. Even if there is no argument given then NIL is considered to be one of the arguments.

Primitives are part of basic syntax of LISP. + is not considered as a part of basic syntax of LISP. It is rather an example of the primitives.

In (setq arg1 arg2), the arg1 is like a variable in which value is stored. It can be a symbol. The value of arg2 got stored in it.

These all can be used as an argument for a primitive. Arguments depend on the type of primitive used. Example for arithmetic operators: numbers are used. For list functions: lists are used.

Prefix notation is always used in LISP Syntax. It doesn't change for different LISP Primitives. That is infix and postfix notations are not used.

In general, the arg2 or argument2 is the value that is to be set on arg1. It can be a number, a list, a symbol, a formula, etc.

The arg1 or argument 1 is like a variable in which value is stored. The arg1 can be anything like a symbol, a list or maybe the first element of a list, etc.

The value of the actual parameter does not change only when the name of actual and formal parameters is same. In all other cases, the value of the actual parameter can change.

Yes, the actual and formal parameters can be of same name. The scope of the formal parameter remains within the procedure in this case.

Yes, the parameters can be passed to procedures. Parameter passing is the most important part of the procedures. Actual parameters are passed to the procedures while function invoking.

Defun is used for defining procedures. defun is the shorthand notation of deine function in LISP programming.