1. Principles of Programming Languages
Hongwei Xi
University of Cincinnati
Spring, 2001
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Introduction

2. Welcome! 20-ECES-730: Principles 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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3. 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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4. Course Overview Operational Semantics What is operational semantics?
Why do we need operational semantics?
How do we formally present operational semantics?
Natural semantics (big step)
Reduction semantics (small step)
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5. 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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Introduction

6. 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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7. What is this course like?
Stressing both mathematical reasoning and implementation skill
Prove theorems
Build systems
Emphasizing mathematical rigor and clarity
“If you can’t explain it, I won’t trust it ”
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8. 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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9. What this course is like?
There is no textbook for this course
Taking notes is a large part of the course
Both studying and experimentation are essential to gaining understanding of the material
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10. 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

11. 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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12. People Teaching Staff Hongwei Xi, Assistant Prof
Swaroop Kavalanekar, Graduate Student
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13. Schedules Lectures: TTh 3:30-4:45PM Classroom: Swift 500 Office Hours:
Thursday 4:30-6:30PM
Or by appointment (preferred)
Or stop by 826 Rhodes
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14. Programming Language Standard ML (SML)
If you know nothing of SML, learn it now!
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15. Homework Approximately 5 or 6 assignments Clarity and elegance count
About one every two weeks
Individual work only unless specified otherwise!
Clarity and elegance count
It is not enough to just “work” on test data
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16. Exams and Grades Midterm (30%) Final (40%) Homework (30%)
Date: Friday, 27 April, 2001
Format: In-class or Take-home
Final (40%)
Date: Thursday, 7 June, 2001
Time: 7:30-9:30AM
Place: Classroom
Homework (30%)
All exams are open-book
Participation can make difference on letter grade
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17. 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 teaching staff are always willing to help
Ask earlier, rather than later
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18. A Plea and A Warning This is my second 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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19. Course Information Everything is on the web!
Course Homepage
Notes, Slides, Handouts, Assignments, Solutions
Please visit the homepage frequently!
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20. Welcome on Board and Enjoy the Ride!
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