commonlisp.md

title	Common Lisp
description	Common Lisp cheatsheet gives you a quick reference to code syntax with examples makes it handy while coding.
created	2020-07-05
updated	2020-07-05

Sample program

(setq name (read))
(princ "Hello ")
(write name)

• read : used to read the data from console
• setq : used to create and assign values to the variables
• princ : used to print the output to the console
• write : used to write output to the console
• ; : Indicates a comment line.

Variables

Multiple ways to declare variables

Example

(defvar x 10)
(write x)

• let and progare used to declare local variables.

(let ((var1  value1) (var2  value2).. (varn  valuen))<expressions>)

• setq is used to declare both global and local variables.

(setq a 10)

Macros

(defmacro macroName (parameter-list))
"Optional string for documentation"
;body

Constants

(defconstant constName value)

Example

(defconstant PI 3.141592)

Operators

Operator type	Description
Arithmetic Operator	+ , - , * , / , rem, mod,incf,decf
Relational Operator	< , > , <= , >=, /= , ==, max, min
Logical Operator	and, or, not
Bitwise Operator	logand, logior, lognor, logxor, logeqv

Conditional statements

1. If

(if [test] [then do this] [else do this])

2. When

(when ([conditional-expr])
    ([do this])
    ([do this])
    ([do this, which returns value]))

3. Case

(cond   (condition1    action1)
        (condition2    action2)
        ...
        (conditionn   actionn))

Loops

1. Loop

(loop (s-expressions))

2. For

(loop for loop-variable in <a list>
   do (action)
)

3. Do

(do ((var1    val1   updated-val1)
      (var2   val2   updated-val2)
      (var3   val3   updated-val3)
   ...)
   (test return-value)
   (s-expressions)
)

4. Dotimes

(dotimes (n val)
  statements

Arrays

(setf arrayName (make-array '(length)))

Lists

(list 1 2 3 4 5)
(list 'a 'b 'c 'd 'e)

List methods	Usage	Description
cons	(cons 'a '(b c)) --> (A B C)	used to put together list items
append	(append '(a b) '(c d)) --> (A B C D)	Used to append lists
reverse	(reverse '(a b c)) --> (C B A)	used to reverse the list items
sort	(sort '(0 5 1 3 2) #'>) --> (5 3 2 1 0)	used to sort the list items
substitute	(substitute 'y 'x '(x 1 x 2)) --> (Y 1 Y 2)	used to substitute the list items with the given value
length	(length '(1 2 3 4 5)) --> 5 used to find the length of a list
count	(count '1 '(1 2 1 2 1)) --> 3	to count the occurence of a list item
remove	(remove 'item list)	removes the given item from list

Hash Table

make-hash-table &key :test :size :rehash-size :rehash-threshold

Structures

(defstruct structureName 
    ; structureElements
)