Lisp EN -- Laboratory 1 -- 2006-2007 -- info.uvt.ro
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Lisp EN -- 2006-2007 -- info.uvt.ro
- Lisp EN -- Laboratory 1 -- 2006-2007 -- info.uvt.ro
- Lisp EN -- Laboratory 2 -- 2006-2007 -- info.uvt.ro
- Lisp EN -- Laboratory 3 -- 2006-2007 -- info.uvt.ro
- Lisp EN -- Laboratory 4 -- 2006-2007 -- info.uvt.ro
- Lisp EN -- Laboratory 5 -- 2006-2007 -- info.uvt.ro
- Lisp EN -- Laboratory 6 -- 2006-2007 -- info.uvt.ro
- Lisp EN -- Laboratory 7 -- 2006-2007 -- info.uvt.ro
- Lisp EN -- Test -- 2006-2007 -- info.uvt.ro
Introduction
[edit]Programming paradigms
[edit]
Concepts
[edit]- Side effects
- Recursion
- High order functions
- First class functions
- Closures
- Symbolic processing
Syntax
[edit]- Atoms
- Numbers
3.14 20 1/3 55.2e-20
- Symbols
a abc 1+ 2pi
- Special symbols
- t
- nil
- Lists
- Special symbols
(1 2) (1 (2 3) (4 (5 6)) 7)
- Special lists
- nil
- ()
- Special lists
- Strings
"abc" "123CDE"
- Symbolic expressions (S-expressions)
("abc" 1 (33 "4"))
- Comments
; this is a comment (print 1) ; this in another comment
Arithmetic expressions
[edit]Examples
[edit]- Comparisons with other programming languages or mathematical notation
- 1 + 2 + 3 * 4 => (+ 1 2 (* 3 4))
- sin(30) => (sin 30)
- (((1 / 2) / 3) / 4) => (/ 1 2 3 4)
Number types
[edit]- integer (extends number)
1 100 123456
- real (extends number)
- rational (extends real)
1/2 2/3
- float (extends real)
1.0 20.33e01 3e-14
- complex
Constants
[edit]- pi
Arithmetic functions
[edit]- + -* /:
(+ 1 2 3 4) => 10 (- 1 2 3 4) => -8 (* 1 2 3 4) => 24 (/ 1 2 3 4) => 1/24
- mod and rem
(mod 7 3) => 1 (rem 7 3) => 1
- 1+ and 1-
(1+ 2) => 3 (1- 2) => 1
- min and max
(min 1 2 3) => 1 (max 1/2 2 33/5) => 33/5
- abs
(abs -2.3) => 2.3
- floor, ceiling, truncate and round
(floor 1/2) => 1 (truncate 1/2) => 1 (ceiling 1/2) => 2 (round 1.5) => 2 (round 2.5) => 2
- sin, cos and tan
(sin (/ pi 2)) => 0.707106...
- signum
(signum -55) => -1 (signum -55/3) => -1 (signum -55.0) => -1.0
- sqrt, exp, expt and log
(sqrt 1/4) => 1/2 (exp 2) => 7.389056 (expt 5/3 2) => 25/9 (log (exp 2)) => 2
Boolean expression
[edit]Questions
[edit]- What is considered true: t and anything except nil.
- Does () represent true or false?
Predicates
[edit]Objec type or identity predicates
[edit]- atom
(atom 'a) => t (atom "a") => t (atom 1) => t (atom nil) => t (atom '(1 2)) => nil (atom ()) => ???
- listp
(listp ()) => t (listp '(1 2)) => t (listp t) => nil (listp nil) => ???
- symbolp
(symbolp t) => t (symbolp nil) => t (symbolp "a") => nil (symbolp 'a) => t (symbolp ()) => ???
- null
(null t) => nil (null 'a) => nil (null nil) => t (null '(1 2 3)) => nil (null ()) => ???
Arithmetic predicates
[edit]- numberp
- integerp
- realp
- rationalp
- floatp
- complexp
- minusp and plusp
(minusp 1) => nil (plusp 1) => t (minusp 0) => nil (plusp 0) => nil
- zerop
(zerop 1) => nil
- <, <=, =, >=, >, and /=
(< 1 2 3) => t (< 1 3 1) => nil (= 1 2 3) => nil (/= 1 2 3) => t
- evenp and oddp
(evenp 1) => nil (oddp 1) => t
Boolean predicates
[edit]- not and null
- and
(and t nil) => nil (and t t) => t (and 1 2 3) => 3 (and 1 nil) => nil
- or
(or t nil) => t (or nil nil) => nil (or 1 2 nil) => 1 (or nil 1 nil) => 1
Equality predicates
[edit]- eq -- verifies identity
(eq 1 1) => t (eq 1 1.0) => nil (eq "a" "a") => nil
- eql -- verifies value
(eql 1 1.0) => nil (eql '(1 2) '(1 2)) => nil (eql "a" "a") => nil
- equal -- verifies representation
(equal 1 1.0) => nil (equal "a" "a") => t (equal "a" "A") => nil (equal '(1 2) '(1 2)) => t
- equalp -- verifies representation ignoring case
(equalp 1 1.0) => t (equalp "a" "A") => t
Lists
[edit]Examples
[edit](1 2 3 4) (a b c d) (1 a b 2 c 3) ((1) (2) (()))
Quoting
[edit]- quote and '
(+ 1 2) => 3 '(+ 1 2) => (+ 1 2)
Functions
[edit]- length
(length ()) => 0 (length nil) => ??? (length '(1 2 3)) => 3 (length '(1 (2 3 4 5) 6)) => 3
- car
(car ()) => nil (car '(1 2)) => 1
- cdr
(cdr ()) => nil (cdr '(1 2 3)) => (2 3)
- Using car and cdr together
(car (cdr '(1 2 3))) => 2 (cadr '(1 2 3)) => 2 (cddr '(1 2 3)) => (3) (caddr '(1 2 3)) => 3
- first, second, ..., tenth
(sixth '(1 2 3 4 5 6 7)) => 6
- nth and nthcdr
(nth 3 '(1 2 3 4 5 6)) => 4 (nthcdr 3 '(1 2 3 4 5 6)) => (4 5 6)
- list
(list 'a 'b 'c 'd) => (a b c d) (list '(1 2) '(3 4)) => ((1 2) (3 4))
- append
(append '(1 2) '(3 4)) => (1 2 3 4) (append 1 2 3) => error!
- reverse
(reverse '(1 2 3 4)) => (4 3 2 1) (reverse '(1 (2 3) 4)) => (4 (2 3) 1)
- member
(member 5 '(1 2 3)) => nil (member 2 '(1 2 3)) => (2 3) (member 2 '(1 (2 3) 4)) => nil
- subst
(subst 'a 1 '(1 2 1 3)) => (a 2 a 3) (subst 'a 1 '(1 (2 1) 3)) => (a (2 a) 3)
User defined functions
[edit]- defun
(defun <function-name> (<argument-1> ...) <statement-1> ...)
(defun my-sum (a b) (+ a b)) (my-sum 1 2) => 3 (defun my-evenp (n) (zerop (mod n 2))) (my-evenp 2) => t
Assignment 1
[edit]Until next Wednesday (2007-03-07) 24:00 you will have to send me by email the following assignment.
When you send the email please include in the subject "[LISP-EN-2] First_name Last_name" for the second year and "[LISP-EN-3] First_name Last_name" for the third year. Please paste the code inside the email, DO NOT ATTACH any files.
Write 10 user defined functions (by using defun), with a minimum of 2 parameters (one parameter is accepted but only as an exceptional case), which uses some of the library functions described in this lab. Please also include a short description for each one and 2 or 3 test cases with the results.
For example:
(defun pol2 (x a b c) (+ (* a x x) (* b x) c)) (pol2 1 2 3 4) => 9 (defun my-< (a b) (minusp (- a b))) (my-< 1 2) => t
Ciprian Dorin Craciun
2007-03-01