Welcome to the CIS Seminar

1
Welcome to the CIS Seminar

• Fall, 2006

2
Taking this for Credit

• Youll do a ½ hour presentation (or you and a
  friend will do a 1 hour presentation).
• This presentation includes background and
  discussion in the wiki.
• You need to participate
• You need to attend every week.

3
Grading

• Presentation 50
• Participation Attendance 50

4
About Your Presentation

• We will pick topics today if possible.
• You need to do background research (hint Google
  doesnt yet cover all information in the
  universe! Try the library )
• You need to make a good wiki page, including
  discussion prompts or problems.
• You need to make good slides
• You need to practice! I will ask for a trial run
  at least 3 days before. If youre not ready Ill
  ask for more trial runs.

5
Scheduling

• History of programming languages (Prof Peterson)
• Haskell (Prof Peterson)
• Mathematica as a programming language (Prof Keck)
  
• Hindley-Milner Type systems (Daniel)
• Computer camp wrapup (Prof Peterson)
• Ruby on Rails (Tim)
• Internship report (Kate)
• Running CMT (Randy Spydell)
• Alex Chiang (HP)
• Tim Chamilard (UCCS)
• Gareth Eaton (DU)
• Eric Friedman (CNet)
• Kate's Dad (???)
• Amanda Tarr (Some crazy game company)
• Possible Student talks C and templates ,
  Prolog, Snobol / Icon,

6
This Terms Theme

• Programming Languages!

7
A Brief History of Programming Languages

• Computer Science is unique in that no one
  language of expression has emerged to supplant
  all others.
• Most other disciplines have one "official"
  language
• standard music notation
• standard math notation
• standards for blueprints technical
  descriptions

8
Why So Many Languages?

• What keeps computing from having one standard
  language that absorbs all others??

9
In The Beginning

• Computers were really expensive!
• Few programs.
• Just write everything in the native language of
  the machine.

LDQ X FMP X
CALCULATE X X STO SUM LDQ Y FMP
Y CALCULATE Y
Y FAD SUM X X
Y Y STO SUM
STORE SUM
Old IBM Assembly
10
The First Real PL Fortran
1954

• It soon became obvious that assembly was hard to
  write andhard to understand. Mathematicians
  wanted to use more familiar notation.

A Fortran II example written byJohn Backus
11
Fortran Innovations

• Math notations (infix expressions)
• Basic control structures IF, DO loops,
  subroutines / functions
• No real linker "Common Blocks" were a
  substitute
• Column oriented syntax (punched cards)

12
Lambda Calculus Strikes!
1958

• Lisp was a language WAY ahead of it's time!
• John McCarthy proposed a language based on
  lambda-calculus and S-expressions (pairs).

13
Lisp Innovations

• Automatic Storage Management
• Purely functional subset
• Defined by a meta-interpreter
• Syntactic simplicity
• Single recursive structure type
• Lisp is still alive and well nowadays it's
  called "Python"

14
Algol
1958

• Algol "Algorithmic Language"
• Algol was a language for both programming and
  formal description of algorithms.

15
Contributions of Algol

• First language with "Modern" syntax
• A language of scholarly publication
• Better "function call" mechanism more
  descriptive
• Led to Pascal and eventually Java
• Adopted as the "machine language" by Burroughs

16
COBOL
1959

• Cobol was a language designed
• to fill the needs of the business
• community (mathematicians and other shady
  academics were responsible for the other
  languages!)
• It was influenced by Grace Hopper's ideas in
  Flow-Matic.

17
Pity the Cobol Programmer

• MULTIPLY B BY B GIVING B-SQUARED.
• MULTIPLY 4 BY A GIVING FOUR-A.
• MULTIPLY FOUR-A BY C GIVING FOUR-A-C.
• SUBTRACT FOUR-A-C FROM B-SQUARED GIVING
  RESULT-1.
• COMPUTE RESULT-2 RESULT-1 .5.
• SUBTRACT B FROM RESULT-2 GIVING NUMERATOR.
• MULTIPLY 2 BY A GIVING DENOMINATOR.
• DIVIDE NUMERATOR BY DENOMINATOR GIVING X.

18
Cobol Innovations

• Extensive I/O capabilities
• Natural language (why?)
• Abandoned native numeric representation
• Emphasized data layout (nested naming)
• This is the language that will not die. You
  could earn big becoming a Cobol programmer.

19
APL
1962

• Ken Iverson was probably the first "mad genius"
  to design a programming that was completely
  unprecedented and unique.
• Good luck figuring this one out

20
APL Contributions

• An amazing economy of expression
• Extreme functional programming many APL
  operators made it into Haskell
• Explored the difficulty of introducing new
  symbols into the PL
• Everyone knew about APL but nobody actually
  used it except crazy math dudes
• Still alive as the "J" programming language

21
Simula
1962
External Class Geometry Geometry Begin !
Subclasses declared in the prefixed block
Point Class Color_Point(C) Character C Begin
... End Rectangle Class Square Begin ...
End ! Variables declared in the prefixed
block Ref(Color_Point) A1 Ref(Point) C,
D Ref(Circle) K Ref(Line) E, F
Ref(Rectangle) R1 Ref(Square) S1 ! Block
body C - New Point(5,6) D - New
Point(20,30) A1 - New Color_Point(3, 4,
'G') K - New Circle(10, C) E - New
Line(C, D) F - X K.Shift (1,1) R1 -
New Rectangle("Rec_R1", 5, 4) S1 - New
Square("Square_S1", 4, 6) S1.Show End of
prefixed block

• Simula expanded on Algol to add objects, classes,
  methods, GC. It is the ancestor of object
  oriented programming.

Ole-Johan Dahl and Kristen Nygaard
22
Simula

• Simula was designed for discrete event based
  simulation something that O-O does very well!
• It took a long time for O-O ideas to hit the
  mainstream (C)