Smalltalk

1
Smalltalk

• Interpreted by
• Alan Frazier
• Brian Sparks

2
History

• Smalltalk was originally designed as a PL that
  would be easy to learn. One of its original
  design intentions was to be a learning
  environment for children.
• It is used for application development for
  teaching purposes.
• 1st language to support a multi-window GUI.

3
Technical design factors

• Paradigm
• Binding times
• Parameter passing
• Data types
• Simplicity Readability
• Runtime Efficiency
• Library Support Debugging help
• Longevity Portability

4
Paradigms Binding

• Smalltalk is known mainly for its efforts to be
  as object oriented as possible.
• Quite possibly the epitome of the object oriented
  paradigm.
• Smalltalk is an interpreted language, like Perl.
• It also uses dynamic binding, a trait common to
  most interpreted languages.

5
Parameter Passing

• Smalltalk uses messages to pass information to
  objects to get them to follow certain behaviors
  specific to that object.
• Ex1 5 factorial
• Ex2 hello size

6
Data Types

• As mentioned before, all data are encapsulated
  into objects.
• Fundamental Data Types, literals
• String hello string bob _at_\
• Number 123 -234 ¾ -½ 4.567 -2.34e10
• Character Y G _at_
• Symbol name atput
• Array (1 2 3 4) (1 two Y) (ab cd ef)

7
Simplicity Readability

• Smalltalk syntax consists of
• Statements (cascaded statements)
• Assignments
• Comments
• Temporary variables
• Blocks of code
• Has a readable syntax and is considered a
  literate language by some.

8
Runtime Efficiency

• Its an interpreted PL,
• With dynamic binding,
• no type declarations.
• What do you expect??

9
Library Support Debugging Help

• A multitude of free class libraries can be found
  on the web.
• Native Smalltalk debugging tools, Oh Yea!

10
Longevity Portability

• Rinse, Wash, Repeat!
• Currently a hot product for prototyping.
• Many commercial free implementations
• GNU Smalltalk
• Squeak
• IBM
• ObjectShare

11
Closing Comments

• Our program
• Smalltalk is definitely a niche language. It
  does have its high points and is very useful for
  certain applications.
• Its popularity is growing and it is being used
  for more commercial projects and may become more
  prominent in the future.

12
References

• http//cgibin.erols.com
• http//www.object-arts.com
• http//www.cs.ucf.edu/courses/cop4331/hughes/Summe
  r1998/Tutorials/Smalltalk/oop.html
• http//www.s-direktnet.de/homepages/neumann/lang_c
  mp.en.htm
• http//www.dylanworld.com/advocacy/competitive.htm
  l