Lisp - Built-in Functions

LISP, especially Common LISP dialect, has a rich set of built-in functions covering a wide range of operations. In this chapter, we're listing down key catogories of functions in LISP.

LISP Manipulation

• car − returns first element of the list.

• cdr − returns rest of the list, excluding first element of the list.

• cons − creates a new list by adding an element to the beginning of the list.

• list − creates a new list of its arguments.

• append − concatenates lists.

• member − checks if an element is part of a list.

Airthmetic Operations

• + − Addition of arguments.

• - − Subtraction of arguments.

• * − Multiplication of arguments

• / − Division of arguments

• mod − Remainder of division of arguments

• max − Maximum of arguments

• min − Minimum of arguments

Predicates

• = − Equality checks on numbers

• eq − Identity comparison

• eql − Deep equality check

• atom − Check on argument as atom, not a list

• listp − To check if argument is a list

• null − To check if list is empty

• numberp − To check if argument is a number

Control Flow

• if − For conditional evaluation

• cond − For multiple conditions

• let − To create local variables

• defvar − To create global variables

• do − To create a loop

I/O

• print − prints expression to console

• write − write expression to console

• read − to read an expression from console

Functions Definition

• defun − to define a function

• lambda − to create an anonymous function

Apart from rich set of functions, LISP provides macros to extend the programming language.