Smalltalk Assignment(AddressBook design and implementation)

• Grading (70 total points possible)
  • Presentation — 10 points
  • Design — 30 points
  • Smalltalk conventions — 5 points
  • Implementation — 15 points
  • Test cases — 10 points

• Mean was a 65/70 — Nice work!

General thoughts

• Spell check!

• Read what you turn in—some printouts used the default font which is nearly impossible to distinguish between () and []

• Label all arrows on pictures

Design first…Implement later!

• Not: “Because we use the dictionary we do not support multiple cards with the same name”

• Instead: “We feel it is imperative that the user has cards with unique names, and it is easy enough to add a distinguishing middle initial or name, so we chose to use the dictionary.”

Overuse of strings

• Fields could have been symbols instead of strings

• Values could have been any object, not just a string

• If it’s not a free-form, arbitrary string, consider using a symbol instead:#name, #address, #phone(comparing strings is expensive)

More overuse of strings

• Return true and false (not 'yes' or 'no', and not True or False)

• Do not return strings to indicate error conditions — remember the question about dynamic typing on the midterm.Use:self error: 'Card for that name not found'

Printing a value

• Returning a string is not printing it

• Overriding the printOn: method teaching the Smalltalk system how to display objects of a class that you write — argument is a Stream object

• Never use a global variable unless you absolutely must — instead, let the user pass you the global variable(e.g., Transcript)