Computer Programming with GNU Smalltalk - Free

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2 Computer Programming with GNU Smalltalk MOVE d'3', W ADD d'4' I don't know if you can guess what this code does but it is obvious that it is more readable than a machine code. So we can say that Assembly language is a higher lever language than machine code. By the way, if you are curious about what the code above does, it just sums up two numbers. Now look at the same code above written in a language named GNU Smalltalk (Hmm, I never heard of it before): 3 + 4 I won't ask if you have guessed what the code above does because I don't know of any way to describe it better than the code line above, if you say no. So, the highest level language when we compare machine code, Assembly and GNU Smalltalk is GNU Smalltalk. Although, the examples we have given to describe the language levels are pretty simple and obvious, don't expect GNU Smalltalk as almost the same with English. It can get sometimes as confusing as Assembly, although it has a reputation as being a very high level language compared to other programming languages commonly used today. We will finish this topic with an important statement, being a higher level language does not mean being a better language. Assembly is also a very commonly used language today because when a language is close to hardware, the control of you over hardware becomes stronger. So, for doing very fundamental hardware programming Assembly is probably a good choice. Also the lower level the language you use the higher control of you over optimization of the code which results in faster programs. Of course, using Assembly to code an office suit like Microsoft Office just because of the advantages of Assembly would be a silly choice because it will result hundreds of times longer, more complex, unreadable and that's why unmaintainable code when it would be coded in a higher level language. So, you should consider all the pros and cons before choosing a programming language for the current project. This also means that you may need to choose different languages for different projects.
Away f rom Hardware Easy -to-Maintain Slower Portable Compiled and Interpreted Languages Higher Lev el Lower Lev el Introduction to Programming World 3 Close to Hardware Hard-to-Maintain Not Portable We mentioned that writing a program is done by using programming languages and there is a step of converting the programs we write from human understandable form to computer understandable form. This process is called compilation if the entire program is converted into machine language at once and kept in computer memory in that form. If the software written in a programming language requires to be compiled before run then this language is called a compiled language. The software doing the compiling process is called compiler. But if the program is converted as we write, that is line by line or more correctly statement by statement then this process is named as interpretation and such languages are called interpreted languages. Software written in interpreted languages are kept in computer memory as the way we write them and every time we execute (or launch, run) them, they are interpreted again into machine language. The software doing the interpretation process is called interpreter. Faster
Page 1 and 2: Computer Programming using GNU Smal
Page 3: To the ant I accidentally crushed y
Page 6 and 7: II We will often use this kind of b
Page 9 and 10: Contents Preface I Who is This Book
Page 11 and 12: Postface 107 About the Author......
Page 13: Chapter 1: Introduction to Programm
Page 17 and 18: Introduction to Programming World 5
Page 21 and 22: like image viewer or PDF reader to
Page 25 and 26: Chapter 2: Introduction to GNU Smal
Page 27 and 28: Introduction to GNU Smalltalk 15 me
Page 29 and 30: Introduction to GNU Smalltalk 17 4.
Page 31 and 32: Objects, Messages and Classes: Part
Page 33 and 34: Unary, Binary and Keyword Messages
Page 37 and 38: Common Classes and Their Usage: Par
Page 43 and 44: setNumerator:setDenominator: Object
Page 47 and 48: Carl tellUsYourLastName Here Carl r
Page 51 and 52: aSet Set ('Soap' 'Toothbrush' ) Obj
Page 53 and 54: new We create a dictionary with new
Page 57 and 58: Chapter 4: Controlling the Flow of
Page 59 and 60: anObject ifTrue: [block-expression-
Page 61 and 62: Controlling the Flow of Execution 4
Page 63 and 64: ] This is the 1. line. This is the
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Controlling the Flow of Execution 5
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Objects, Messages and Classes: Part
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The general syntax for creating cla
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ourObjectName := SubclassName new O
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] ] 'Woof!' printNl. Animal subclas
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Animal setAnimalNumber: 1. dog setN
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printString, ' years old.'; cr. ] ]
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me := Human new. me setName: 'Canol
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getAge [ ^age ] Objects, Messages a
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Chapter 6: What to Do Next How Can
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What to Do Next 81
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Installing Programming Environment
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./configure make make install Insta
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Appendix B: ASCII Table Number (Dec
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Appendix C: Answers of Review Quest
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Chapter 2 Answers of Review Questio
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value, directly. Answers of Review
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Answers of Review Questions 95 exam
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]. Transcript cr. Answers of Review
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2. called inheritance. Encapsulatio
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setHonesty: rateOfHonesty [ "Honest
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Answers of Review Questions 103 of
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Alphabetical Index accessor 66 Argu
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Postface Postface 107 Now, we are a
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Computer Programming with GNU Smalltalk - Free

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