1 / 45

Comparative Programming Languages

Language Comparison: Scheme, Smalltalk, Python, Ruby, Perl, Prolog, ML, C++/STL, Java. Comparative Programming Languages. Fundamentals of Functional Programming Languages.

msholar
Download Presentation

Comparative Programming Languages

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Language Comparison: Scheme, Smalltalk, Python, Ruby, Perl, Prolog, ML, C++/STL, Java Comparative Programming Languages

  2. Fundamentals of Functional Programming Languages • The objective of the design of a functional programming language (FPL) is to mimic mathematical functions to the greatest extent possible • The basic process of computation is fundamentally different in a FPL than in an imperative language • In an imperative language, operations are done and the results are stored in variables for later use • Management of variables is a constant concern and source of complexity for imperative programming • In an FPL, variables are not necessary, as is the case in mathematics CS 363 Spring 2005 GMU 2

  3. Fundamentals of Functional Programming Languages • In an FPL, the evaluation of a function always produces the same result given the same parameters • This is called referential transparency CS 363 Spring 2005 GMU 3

  4. Lisp • Lisp – based on lambda calculus (Church) • Uniform representation of programs and data using single general data structure (list) • Interpreter based (written in Lisp) • Automatic memory management • Evolved over the years • Dialects: COMMON LISP, Scheme CS 363 Spring 2005 GMU 4

  5. Smalltalk – Object Orientation • Smalltalk – a dynamically typed object oriented programming and functional language designed at Xerox PARC by Alan Kay, Dan Ingalls, Ted Kaehler, Adele Goldberg, during the 1970s. • Released as Smalltalk-80 • Influenced the development of languages such as Objective-C, Java and Ruby • Everything is an object • Everything is available for modification. If you want to change the IDE, you can do it • Types are dynamic -- you don't have to define types in the code • Garbage collection is built in, invisible to the developer. 5

  6. Squeak • Squeak is an open, highly-portable Smalltalk-80 implementation whose virtual machine is written entirely in Smalltalk • The image below was created in Squeak, and illustrates several of Squeak's abilities, including the ability to scale and rotate bitmap images at any colour depth, anti-aliased TrueType fonts and vector graphics 6

  7. Ruby • Ruby – combines syntax inspired by Python and Perl with Smalltalk-like object-oriented features • Ruby is an interpreted language. • Created by Yukihiro "Matz" Matsumoto, started working on Ruby in Feb. 1993 and released it to the public in 1995. • Name chosen to reflect the language's Perl heritage. • Designed Ruby to follow the principle of least surprise - the language should be free from traps and inconsistencies of other languages 7

  8. Python • Python is an interpreted, interactive programming language created by Guido van Rossum in 1990 • Originally as a scripting language for Amoeba OS capable of making system calls. • Amoeba distributed operating system is a microkernel-based research operating system written by Andrew S. Tanenbaum at Vrije Universiteit • The aim of the project was to build a timesharing system that appeared to the user as a single machine even though it was running on multiple machines. 8

  9. Python • Python • Often compared to Tcl, Perl, Scheme, Java, and Ruby • Developed as an open source project, managed by the non-profit Python Software Foundation. • Python is a multi-paradigm language, like Perl, Oz or C++ and unlike Smalltalk or Haskell • Rather than forcing coders to adopt one particular style of coding, it permits several • Object orientation, structured programming, functional programming are all supported • Python is dynamically type-checked and uses garbage collection for memory management • origin of the name - after the television series Monty Python's Flying Circus 9

  10. Python • Python (from wikipedia) • Many similarities to Perl • However, Python's designers reject Perl's exuberant syntax in favor of a more spare, less cluttered one • As with Perl, Python's developers expressly promote a particular "culture" or ideology (http://python.org/dev/culture.html) based on what they want the language to be, favoring language forms they see as "beautiful", "explicit" and "simple". • Although Python is sometimes classified as a "scripting language", it has been used to develop many large software projects such as the Zope application server 10

  11. Scheme (dr scheme, guile) (define (gcd u v) (if ( = v 0) u (gcd v (remainder u v)) ) ) (define (reverse l) (if (null? l) l (append (reverse (cdr l))(list (car l))) ) ) CS 363 Spring 2005 GMU 11

  12. Scheme (dr scheme, guile) Using guile (gnu scheme): (load "slides.scm") (gcd 56 108) --> 4 (reverse '(2 3 556)) --> (556 3 2) CS 363 Spring 2005 GMU 12

  13. Common Lisp (clisp) (defun mygcd (u v) (if (= v 0) u (mygcd v (rem u v)) ) ) (defun myreverse (l) (if (null l) l (append (myreverse (cdr l))(list (car l))) ) ) ;; (load "slides.lsp"), (mygcd 56 108) --> 4 ;; (myreverse '(2 3 556)) --> (556 3 2) 13

  14. Smalltalk (Squeak - inisqueak) myGcd: numTwo " 112 myGcd: 224 --> 112” (numTwo = 0) ifTrue: [^self]. ^numTwo myGcd: self \\ numTwo. myReverse "#(1 2 3 43 a b) myReverse -> ($b $a 43 3 2 1 )" (self size = 0) ifTrue: [^self]. ^self allButFirst myReverse, self first asOrderedCollection. 14

  15. Gnu-Smalltalk – gst !SequenceableCollection methodsFor: 'algorithms'! "Or use Array, but that limits your objects." myCount " #(1 2 3 $a $b $c myCount! --> 6 In gst: Filestream inFile: count.st " (self size = 0) ifTrue: [^0]. ^(1 + (self copyFrom: 2) myCount). ! 15

  16. Gnu-Smalltalk – gst (cont.) myReverse "#(1 2 3 43 a b) myReverse -> • ($b $a 43 3 2 1 )" | temp | (self size = 0) ifTrue: [^self]. temp := OrderedCollection new: 1. temp add: self first. ^(self copyFrom: 2) myReverse, temp. !! 16

  17. Gnu-Smalltalk – gst (cont.) !Number methodsFor: 'algorithms'! myGcd: numTwo "120 myGcd: 200! --> 40" (numTwo = 0) ifTrue: [^self]. ^numTwo myGcd: self \\ numTwo. !! 17

  18. Ruby (ruby) def myGcd(numOne, numTwo) if numTwo == 0 return numOne end return myGcd(numTwo, numOne % numTwo) end def myReverse(list) if list.length == 1 return list end return myReverse(list[1..list.length-1]).concat([list[0]]) end 18

  19. Ruby - “Class version”count.rb class Integer def myGcd(numTwo) if numTwo == 0 return self else return numTwo.myGcd(self % numTwo) end end end - load “file.rb” into the Ruby interpreter (eval.rb) - 120.myGcd(500) --> 20 19

  20. Ruby - “Class version” class Integer def greet print "Hello world\n" end def plus(numTwo) return self + numTwo end def times(numTwo) return self * numTwo end end - load “file.rb” into the Ruby interpreter (eval.rb) - 120.greet --> “Hello..”, 3.plus(4).times(5) -> 35 20

  21. Ruby (non-class vers.) def myCount (mylist) if mylist.length == 0 return 0 else return 1 + myCount(mylist[1..mylist.length-1]) end end print "Length of [1,2,3,4,5,6]= ", myCount([1,2,3,4,5,6]), "\n" To run: ruby count.rb 21

  22. Ruby (class vers.) class Array def myCount if self.length == 0 return 0 else return 1 + self[1..self.length].myCount end end end This version is “object oriented”... [3,4,5,6,7,78].myCount --> 6 22

  23. Python (python) def myGcd(numOne, numTwo): if(numTwo == 0): return numOne return myGcd(numTwo, numOne % numTwo) def myReverse(mylist): if len(mylist) == 1: return mylist return myReverse(mylist[1:len(mylist)]) + myReverse([mylist[0]]) 23

  24. Python (python) def myCount (mylist): if len(mylist) == 0: return 0 else: return 1 + myCount(mylist[1:len(mylist)]) print "Length of [1,2,3,4,5,6]= ", myCount([1,2,3,4,5,6]) To run: python count.py 24

  25. Perl sub gcd { if ($_[1] == 0) { return $_[0]; } else { return gcd($_[1], $_[0] % $_[1]); } } sub count { my @ls; @ls = @_; if (scalar(@ls) == 1) { 1; } else { count(@ls[1..$#ls]) + 1; } } 25

  26. Perl sub myReverse { my @templis; if (scalar(@_) == 0) { return (); } else { @templis = myReverse(@_[1..$#_]); push(@templis, $_[0]); return @templis; } } 26

  27. Prolog gcd(Num1, 0, Num1). gcd(Num1, Num2, GCD) :- Rem is Num1 mod Num2, gcd(Num2, Rem, GCD). count([],Total , Total). count([_|Rest], Counter, TotalCount) :- NewCount is Counter + 1, count(Rest, NewCount,TotalCount). /* consult('gcd.pl'). gcd(28, 100, X). count([3,4,5,6,7],0, X). */ 27

  28. Prolog append([],List, List). append([First|Rest], List2, [First|List3]) :- append(Rest, List2, List3). myreverse([],[]). myreverse([First|[]],[First]). myreverse([First|Rest], NewList) :- myreverse(Rest, ReversedList), append(ReversedList,[First], NewList). /* ?- consult('reverse.pl'). ?- myreverse([11,23, 0,42,18,90, 1],X). X = [1, 90, 18, 42, 0, 23, 11] */ 28

  29. ML (sml) fun gcd(num1, 0) = num1 | gcd(num1,num2) = gcd(num2, num1 mod num2); fun count([]) = 0 | count(first::rest) = 1 + count(rest); (* - use "gcdcount.sml"; - gcd(28, 124); val it = 4 : int - count([45,2,7,8,1,23,18]); val it = 7 : int *) 29

  30. ML (sml) fun reverse(L) = if L = nil then nil else reverse(tl(L)) @ [hd(L)]; fun reverse2([]) = [] | reverse2(first::rest) = reverse2(rest) @ [first] (* [] can be used for nil - use "reverse.sml"; - reverse2([1,2,3,4]); val it = [4,3,2,1] : int list -val x = [[1,2],[3,4]] : int list list - reverse(x); - val it = [[3,4],[1,2]] : int list list *) 30

  31. C++ int gcd(int num1, int num2) { if (num2 == 0) return num1; else return gcd(num2, num1 % num2); } 31

  32. C++ (STL) int count(list<int> lis) { if (lis.size() == 0) return 0; else { lis.pop_front(); return 1 + count(lis); } } 32

  33. C++ (STL) list<int> reverse(list<int> lis) { if (lis.size() == 0) return lis; else { int first = *lis.begin(); lis.pop_front(); list<int> reversed; reversed = reverse(lis); reversed.push_back(first); return reversed; } } 33

  34. Java int gcd(int num1, int num2) { if (num2 == 0) return num1; else return gcd(num2,num1 % num2); } 34

  35. Java int count(List lis) { if (lis.isEmpty()) // or lis.size() == 0 return 0; else return 1 + count(lis.subList(1, lis.size())); } 35

  36. Java List reverse(List lis) { if (lis.isEmpty()) return lis; else { Integer first = (Integer)lis.get(0); List temp = reverse(lis.subList(1,lis.size())); temp.add(temp.size(), first); return temp; } } 36

  37. Squeak Browser Window – Lists classes and methods in classes

  38. Squeak Workspace WindowTo “run” each line, middle-button click, choose “do it” or “print it”

  39. Squeak Transcript WindowTo “run” each line, middle-button click, choose “do it” or “print it”

  40. Gnu Smalltalk Browser Window

  41. Worksheet window Transcript window To “run” a line, right click and choose “do it” and/or “print it” Gnu Smalltalk, X11Worksheet and Transcript

  42. Note the use of “!” at the end of each line. Also, printNl is specific to gst. Gnu Smalltalk - gst

  43. Ruby – example run, see count.rb

  44. Ruby – example run from eval.rb

  45. Python – example run, see count.rb

More Related