1. Organization of Programming Languages
Hongwei Xi
University of Cincinnati
Winter, 2001
10 December 2018
Introduction

2. Welcome! 20-ECES-403: Organization of Programming Languages
Introduction to fundamental principles in programming language design and implementation
Emphasis on the use of mathematical methods in programming language studies
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Introduction

3. Software Crisis
Faulty and fragile software becomes more and more common
Security breaches happen more and more frequently
Maintenance cost skyrockets
Programming productivity stagnates
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4. Programming Languages
Ideally, a programming language should
be simple and general
permit extensive error checking
facilitate proofs of program properties
Possess a correct and efficient implementation
… …
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Introduction

5. Programming Languages
Invariably, there are conflicts among these expectations
Language design must resolve such conflicts with careful attention to the needs of the user
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Introduction

6. Programming Paradigms
Imperative programming
FORTRAN, Algol 60, C, Pascal
Functional programming
LISP, SML, Haskell
Object-oriented programming
Smalltalk, C++, Java
Logic programming
Prolog
… …
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Introduction

7. Course Overview Syntactic Structure Expression notations
Prefix, Postfix, Infix, Mixed
Abstract Syntax Trees
Lexical Analysis
Context-free Grammars
Backus-Naur Form (BNF)
Ambiguity
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8. Course Overview Structured programming Syntax-directed control-flow
Programming with invariants
Proofs rules for partial correctness
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9. Course Overview Procedure activations What is a procedure?
Parameter-passing methods
call-by-value, call-by-name, call-by-reference, call-by-value-result
Scope rules for names
Activation records
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10. Course Overview Object-oriented programming What is an object?
Object-oriented thinking
Inheritance
code reuse
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11. Course Overview Type Systems What is type safety?
What are the advantages of typed languages?
What are the disadvantages of typed languages?
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12. Course Overview Type Inference Polymorphism
Do types have to be obtrusive to programming?
Is it a good practice to omit writing types as much as possible?
Polymorphism
How can polymorphism help code reuse?
How can polymorphism enforce data abstraction?
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13. Course Overview Subtyping Objects, Classes and Inheritance
When is one type a subtype of another?
How can subtyping help code reuse?
Objects, Classes and Inheritance
How can we build flexible and extensible software?
How is subtyping related to inheritance?
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14. What is this course like?
You will have to work hard in order to keep up!
Many ideas may sound unfamiliar to you. They are often formal and take time to “sink in”.
Assignments often require both mathematical reasoning and implementation skill.
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15. What is this course like?
Most of all, it’s a lot fun!
Elegant interplay between theory and practice
Rapid exposure to many fundamental ideas
Enormous potential for pursuing further studies in language design and implementation
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Introduction

16. What this course is not!
This is not a course on your top 10 favorite programming languages
We care about fundamental principles, not fads!
This is not a compiler course
This course can be of great help for you to learn compiler construction
Nonetheless, you will be doing a lot of programming!
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Introduction

17. Schedules Lectures: Office Hours: 3-6PM Wednesdays
Time: MWF 10-10:50AM
Place: 821B Rvschl
Office Hours: 3-6PM Wednesdays
Or by appointment
Or stop by 826 Rhodes Hall
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18. Programming Languages
Standard ML (preferred)
C, C++, Java
If you use none of these languages, you need permission to register
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19. Homework Approximately one assignment each week
Individual work only unless specified otherwise!
Clarity and elegance count
It is not enough to just “work” on test data
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20. Exams and Grades Midterm Final Homework (25%) All exams are open-book
Friday, Feb 9, 2001
In-class (25%)
Final
8-10AM, Monday, Mar 12
In-class (50%)
Homework (25%)
All exams are open-book
Participation can make a difference on letter grade
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Introduction

21. Academic Integrity Strict adherence to the university guidelines
All work must be solely your own!
If you have difficulty keeping up, ask for help!
The instructor is always willing to help
Ask earlier, rather than later
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22. A Plea and A Warning This is my first time to offer such a course
I’m likely to be overly ambitious
I’m certain to make (many) mistakes
But I’ll do my best to run the course smoothly
Please be patient and ask a lot of questions
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23. Course Information Everything is on the web!
Course Homepage
Notes, Slides, Handouts, Assignments, Solutions
Please visit the homepage frequently!
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