Functional programming -- 2008-2009 -- info.uvt.ro/Laboratory 1

Functional programming (Spring 2010): front; laboratory: agenda, references, projects, tools; notes (normal paced): 1, 2, 3, 4, 5, 6, 7, 8 (Spring 2009); notes (fast paced): 1, 2, 3, 4 (Spring 2010) (discontinued); applications: robots; mailing list: send mail, view archive, subscribe; author: Ciprian Dorin Craciun, [email protected];

Optional (but highly recommended) reading

The following essays are stolen from Shriram Krishnamurthi:

• Beating the Averages, by Paul Graham;
• Teach Yourself Programming in Ten Years, by Peter Norvig;
• The Perils of JavaSchools, by Joel Spolsky;

References

From the book Practical Common Lisp:

• (m) Chapter 1., Introduction: Why Lisp? (the entire chapter);
• (m) Chapter 2., Lather, Rinse, Repeat: A Tour of the REPL (all sections from the Free Your Mind: Interactive Programming section, up to, and including, the "Hello, World," Lisp Style section; optionally the entire chapter);
• (m) Chapter 4., Syntax and Semantics (all sections from the beginning up to, but excluding, the Macros section, but also read the Truth, Falsehood, and Equality section);

Overview

Concepts

• programming paradigms:
  • imperative;
  • declarative:
    • functional;
    • logic;
• functional programming specific concepts:
  • side-effects;
  • recursion;
  • high-order functions;
  • first class functions;
  • (lexical) closures;
  • continuations;
  • lazy evaluation;
  • (hygienic) macros;

Languages

• pure functional:
  • Haskell;
• mainly functional:
  • Lisp:
    • Scheme;
    • Common Lisp;
  • Erlang;
• supporting functional style:
  • Python;
  • Ruby;
  • JavaScript;
  • Lua;

Tools

GNU CLISP

• Common Lisp implementation;
• GNU CLISP -- official site;
• GNU CLISP Win32 package;

PuTTY

• SSH client for remote access to the university's server goliat.info.uvt.ro;
• PuTTY -- official site;
• PuTTY Win32 package;

SciTE

• Lisp aware text editor for Windows;
• SciTE -- official site;

Basic expressions

Numbers

3.14
20
1/3
55.2e-20

Symbols

abc
function-1
min-max
1 
2pi
<<
>>
string->

Strings

 "abc"
 "123CDE"

Lists

(1 2)
(1 (2 3) (4 (5 6)) 7)
(1 abc 2 cde)
("abc" 1 (33 "4"))
()
(1 () a)
(() ())

Comments

; this is a comment
(print "hello") ; this in another comment

Basic operations

Arithmetic expressions

• , -, *, /, mod, rem:

(  1 2 3 4) ; => 10
(- 1 2 3 4) ; => -9
(* 1 2 3 4) ; => 24
(/ 1 2 3 4) ; => 1/24
(mod 7 3) ; => 1
(rem 7 3) ; => 1

• 1 , 1-:

 (1  2) ; => 3
 (1- 2) ; => 1

• min, max:

(min 1 2 3) ; => 1
(max 1/2 2 33/5) ; => 33/5

• abs, floor, ceiling, trucncate, round:

(abs -2.3) ; => 2.3
(floor 1/2) ; => 1
(truncate 1/2) ; => 1
(ceiling 1/2) ; => 2
(round 1.5) ; => 2
(round 2.5) ; => 2

• sqrt, exp, expt, log:

(sqrt 1/4) ; => 1/2
(exp 2) ; => 7.389056
(expt 5/3 2) ; => 25/9
(log (exp 2)) ; => 2

• signum:

(signum -55) ; => -1
(signum -55/3) ; => -1
(signum -55.0) ; => -1.0

• sin, cos, tan:

(sin (/ pi 2)) ; => 0.707106...

Arithmetic predicates

• zerop, plusp, minusp:

(zerop 0) ; => t
(zerop 1) ; => nil
(plusp 1) ; => t
(plusp -1) ; => nil
(plusp 0) ; => nil
(minusp -1) ; => t
(minusp 1) ; => nil
(minusp 0) ; => nil

• <, <=, =, >=, >, /=:

(< 1 2 3) ; => t
(< 1 3 1) ; => nil
(= 1 2 3) ; => nil
(/= 1 2 3) ; => t

• evenp, oddp:

(evenp 1) ; => nil
(oddp 1) ; => t

Boolean expressions

• not, null:

(not nil) ; => t
(not ()) ; => t
(not t) ; => nil
(not 1) ; => nil
(null nil) ; => t
(null ()) ; => t
(null '(1 2 3)) ; => nil
(null 1) ; => nil

• and, or:

(and t nil) ; => nil
(and t t) ; => t
(and 1 2 3) ; => 3
(and 1 nil) ; => nil
(or t nil) ; => t
(or nil nil) ; => nil
(or 1 2 nil) ; => 1
(or nil 1 nil) ; => 1

Type predicates

• atomp:

(atom 'a) ; => t
(atom "a") ; => t
(atom 1) ; => t
(atom nil) ; => t
(atom '(1 2)) ; => nil
(atom ()) ; => t

• listp:

(listp ()) ; => t
(listp '(1 2)) ; => t
(listp t) ; => nil
(listp nil) ; => t

• symbolp:

(symbolp t) ; => t
(symbolp nil) ; => t
(symbolp "a") ; => nil
(symbolp 'a) ; => t
(symbolp ()) ; => nil

• numberp, integerp, realp, rationalp, floatp, complexp;

Equality predicates

• eq, eql, equal, equalp

(eq 1 1) ; => t
(eq 'a 'a) ; => t

(eq 1.0 1.0) ; => nil
(eq "a" "a") ; => nil
(eq 1 1.0) ; => nil
(eq "a" "A") ; => nil
(eq "a" 'a) ; => nil

(eql 1.0 1.0) ; => t
(eql "a" "a") ; => nil
(eql 1 1.0) ; => nil
(eql "a" "A") ; => nil
(eql "a" 'a) ; => nil

(equal 1.0 1.0) ; => t
(equal "a" "a") ; => t
(equal 1 1.0) ; => nil
(equal "a" "A") ; => nil
(equal "a" 'a) ; => nil

(equalp 1.0 1.0) ; => t
(equalp "a" "a") ; => t
(equalp 1 1.0) ; => t
(equalp "a" "A") ; => t
(equalp "a" 'a) ; => nil

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The current page is a simplified view of the page Laboratory 1 from the previous years, which in turn is based on Laboratory 1 by Cornel Izbasa;