CSC302 2007S, Class 30: Ruby (3)

Admin:
* Beware!  Friday the 13th falls on Friday this month.
* Don't forget next week's Tuesday extra.
* I'd like to hear prospective presentation groups on Monday and prospective topics on Friday.
* Reading for Wednesday distributed (there is no reading for Monday).

Overview:
* About the Presentations.
* Rails.
* Convention and Introspection.
* Ruby vs. Java, Revisited.

/Looking forward to the last two weeks of class/

* Week 13: Presentations
* Week 14:
  * Monday: Presentations
  * Wednesday: Epigrams on Programming
  * Friday: Review and Evaluation
* Finals week:
  * Final - Take home; think about due date

/About Presentations/

* Important curricular issue - Need the experience of presenting
  technical matter (that is, CS STUFF) to your peers and to other 
  people, in a relatively formal setting
  * Sometimes presentations happen in Tutorial (but not always)
  * Usually presentations happen in Software Design (but not always)
  * 302 is another natural candidate
* In addition, gives you the opportunity to pick a few more topics

* Presentations done in groups of three
* You get the whole class period
  * Typically five minutes gets used for adminstrative stuff
  * Thirty minutes for the presentation itself
  * Ten minutes for Q&A
  * Five minutes of slack
* How should you present?
  * Norm: Powerpoint
  * Also: Whiteboard
  * NOT! Read a script with no visuals
  * Maybe - Lab ; Round Robin Recitation ; ...
* Readings? - YES  (Preferably one per class)
* What?
  * See the web page
  * Yes, you can do more practical stuff, too, without penalty

/Today's Readings: Rails/

* Rails is responsible for much of Ruby's popularity
* Rails is a popular Web development environment
  * Rails is enabled by Ruby
* What aspects of Web app development does Rails automate that
  are a pain to do by hand?
  * Generating some web pages for you
    * For each table in the database
      * A page to view an entry
      * A page to edit an entry
      * A page to add an entry
      * A page that lists all entries
  * Most key queries are abstracted into library routines
  * The interface between CGI/Post/Get and methods
  * EACH OF THE THINGS RAILS GENERATES IS MODIFIABLE
* What aspects does Rails seem to neglect?
  * Doesn't really help design wicked-neat looking Web pages
* What view of the world does Rails promote?
  * MVC
* Rails depends on Ruby.  How?
* What about this "ten times faster" claim?
  * Lots of articles say this, including ones by former sceptics
  * But often for straightforward applications, without much
    complicated application logic
  * Long standing evidence that "lines per day" is consistent for
    most programmers and is independent of language
  * Try it?

/Why Ruby? - Convention and Introspection/

* Introspection - The ability to ask about methods and stuff
  More generally, the ability to ask objects about themselves
  (and to have the answers represented as objects)
  * In Ruby, class, methods, etc.
* Example: Unit Testing Framework
  * Look for all classes whose name matches a certain pattern ;
    assume such classes represent unit tests (e.g., UT_)
  * Within that class, look for all zeroary methods whose 
    names start with a certain pattern (e.g., test_)
  * Call each such method

Other reasons to like Ruby
* Scripting model
* Who cares about types?