What's your vanity rank?

A vanity search is when you type your own name into a search engine.

Now, most of us vanity searchers have learned that we are not alone -- there are pretenders out there using our names! So I propose a new term: "Vanity rank". To determine your vanity rank, simply do a vanity search and find the first link that refers to you rather than some doppelganger.

What's my vanity rank? At time of writing -- using Google -- it is 2 as Daniel Prager, and 1 as Dan Prager.

Please look out for my coming book, "How to boost your vanity rank", Narcissus Press, a subsidiary of Mirror Corp.

Why Scheme rocks

Scheme is a modern Lisp dialect. It's what I program in for fun, and to learn new stuff.

Why is it so great? In a word, meta-programming. I can bend the language to my will.

For example, I have just added my own tracing to function definitions, without touching the insides of the function. Instead of using the built-in (define ...) I use my own 12-line* macro (define-with-trace ...). Now all I need to do is figure out how to redefine define.

Here is a more poetic endorsement.


* Plus 4 lines of auxiliary code.

Let My Textbooks Go!

There are three problems with prescribed textbooks:

1. A generally low standard: Feyman's anecdote. Has anything changed since the 60's?
   
2. An inflated sticker price: A NY Times article explains how textbook publishers are like big pharma.
   
3. Limited content: So learn how to search the interweb!
   

Textbooks are starting to be given away for free. One free one that I have bought -- because I wanted a dead leaves version -- "one of the great classics of Computer Science" - Paul Graham.

This is free as in free beer, which addresses point 2. Point 1, the generally low standard, might be helped by more collaborative work on the content, taking a leaf out of the free software movement.

We'll see ...

Unit testing vs Scenario testing

Miško Hevery gives some excellent advice on designing testable software here, and elaborated here:

• Unit Testing as the name implies asks you to test a Class (Unit) in isolation.
• If your code mixes Object Construction with Logic you will never be able to achieve isolation.
• In order to unit-test you need to separate object graph construction from the application logic into two different classes
• The end goal is to have either: classes with logic OR classes with “new” operators.

Here's the explanation / summary:

Asking for your dependencies instead of constructing them withing the application logic is called “Dependency Injection” and is nothing new in the unit-testing world. But the reason why Dependency Injection is so important is that within unit-tests you want to test a small subset of your application.

The requirement is that you can construct that small subset of the application independently of the whole system. If you mix application logic with graph construction (the new operator) unit-testing becomes impossible for anything but the leaf nodes in your application.

Without Dependency Injection the only kind of testing you can do is scenario-testing, where you instantiate the whole application and than pretend to be the user in some automated way.

My emphasis.

Now, this is not to say that you don't need scenario testing, but I have found by bitter experience that trying to mock bits and pieces in scenario tends to be more trouble than it is worth: You end up with large and unwieldy pieces of testing infrastructure.

My current recommendation is that you need to test in both isolation and integration:

1. For isolation (unit testing) use TDD and dependency injection, or DBC
2. For integration, use scenario-based testing on the actual application using some kind of scripting interface.

Other specialist tools may be useful. For example, for highly graphic applications it is invaluable to be able to step-through the scenario tests to visually confirm what is happening on-screen. Visual diagnostics are also a great help for this "semi-manual" testing.

Amazon's recommendation system is too good

Amazon makes it too easy to reliably find -- and purchase -- good books.

The histogram of star-ratings, the user reviews, the cross-referencing with other books bought by people who bought a particular item, and what people ended up buying who looked at all make it easy to track down top books in any given area. Not to mention the access to second-hand books, especially for out-of-print items.

Coupled with the recent strength of the Aussie dollar and the exorbitant cost of purchasing locally, Amazon has proved a recent drain on my finances and a burden to my bookshelves.

So I am resolved: I am not ordering any more books from Amazon for the rest of 2008.

Tickle the Mickle

The kids and I invented a new game today, called "Tickle the Mickle".

1. A player announces, "I am the Mickle!", and lies supine (tummy up) on the couch or floor.
2. Everyone else says, "Tickle the Mickle!", and starts tickling the Mickle.
3. This continues until the Mickle says "Stop!".
4. Someone else takes a turn to be the Mickle.

In a competitive game the winner is the Mickle who can endure the most tickling.

Alan Kay on Research into Learning and Teaching

SecretGeek asked Alan Kay about the paper "The Camel Has Two Humps", and received a fascinating reply. Excerpts:

Notion 1: Good science can rarely be pulled off in an environment with lots of degrees of freedom unless the cause and effect relationships are really simple. Trying to assess curricula, pedagogy, teaching, and the learners all at once has lots of degrees of freedom and is *not* simple.

So for example we've found it necessary to test any curriculum idea over three years of trials to try to normalize as much as possible to get a good (usually negative) result.

Notion 2: Most assessments of students wind up assessing almost everything but. This is the confusions of "normal" with "reality".

For example, in our excursions into how to help children learn powerful ideas, we observed many classrooms and got some idea of "what children could do". Then I accidentally visited a first grade classroom (we were concerned with grades 3-6) in a busing school whose demographic by law was representative of the city as a whole. However, every 6 year old in this classroom could really do math, and not just arithmetic but real mathematical thinking quite beyond what one generally sees anywhere in K-8 [kindergarten and grades 1 through 8].

This was a huge shock, and it turned out that an unusual teacher was the culprit. She was a natural kindergarten and first grade teacher who was also a natural mathematician. She figured out just what to do with 6 year olds and was able to adapt other material as well for them. The results were amazing, and defied all the other generalizations we and others had made about this age group.

This got me to realize that it would be much better to find unusual situations with "normal" populations of learners but with the 1 in a million teacher or curriculum.

Kay gives two examples of quite famous teachers who have written books about their methods:

I found Tim Gallwey [Inner Tennis, Inner Work, etc.], who could teach anyone (literally) how to play a workable game of tennis in 20 minutes, and observed him do this with many dozens of learners over several years.

I found Betty Edwards [Drawing with the Right Side of the Brain] who could teach (again literally) anyone to draw like a 2nd year art student in one intense week.

It is also an interesting social question as to why it is ok to celebrate amazing teachers in film -- e.g. Jaime Escalante in Stand and Deliver -- but not to look more closely at their methods and try to work with them to re-jig teacher identification, training and school curricula.