Flash Cards Kata and the transformation priority premise

I began the new year by resolving to complete the PCL (Peter Siebel's) book. Around the same time, another interesting post by Uncle Bob appeared on the WWW. A discussion on the TDD yahoogroups spurred me to try a Kata - two-sided Flash Cards.

Looked easy enough to test my new-found Lisp skills. Although I was not consciously choosing the next test / step based on the transformation priority, I was curious to know if I had been doing it all along without knowing it.

This innocuous looking kata had me stuck initially - what is the right first step? Trash-canned the first couple of attempts. The third attempt was slow but I succeeded. I did it again in C# just to see if the language had any bearing on my method. This time I was faster because I was familiar with the trail now.

1. I am not wiser with regard to the priority premise - I found I used a bunch of transformations that were not part (bold) of the original list (shown in blue below). As a result, their priorities are unknown. This was the proverbial rain on my parade.
2. Also in the C# variant, I found a couple of tests where I needed multiple transformations to get to the next green & I could not figure out a smaller test.

Note: Check the "speaker notes" in case things get dense especially with the Lisp one. Use the menu button at the bottom-right to get to the presentation link

Attempt#1 Flash Cards Kata in Lisp

TEST User should be asked a question

• {} => statement

TEST A right ans should be confirmed

• P5 (statement->statements) adding more unconditional statements.

TEST A wrong ans should be corrected

• P6 (unconditional->if) splitting the execution path

TEST Diff card and a right ans

• P4 (constant->scalar) replacing a constant with a variable or an argument

TEST Diff card and a wrong ans

• constant => expr

TEST Multiple cards

• {} => loop (statement)

TEST Answers are case insensitive

• exprX => exprY

TEST Answers can have leading/trailing whitespace

• value => expr

Attempt#2 Flash Cards Kata in C#
TEST User is asked the question

• P2 nil -> constant

TEST User is asked another question (triangulate)

• {} => statement *** Play()
• constant => field *** LastQuestionAsked
• void => statement *** Ask() - is there a smaller step here?

TEST A correct ans is confirmed

• P2 nil -> constant

TEST A wrong ans is corrected

• P5 (unconditional->if) splitting the execution path *** Play()
• P4 (statement->statements) adding more unconditional statements
• nil => expr *** User.WhoAnswers
• field assignment *** User.ctor
• constant => field *** User.LastConfirmationReceived
• void => statement *** User.Notify

TEST A diff question and a right answer

• P4 constant => scalar arg

TEST A diff question and a wrong ans

• constant => expression

TEST Two cards

• {} => statements

TEST Multiple cards

• {} => loop
• P4 (statement->statements) adding more unconditional statements *** User
• field assignment *** User.ctor

TEST Case insensitive answers

• exprX => exprY

TEST Trim leading/trailing spaces

• value => expr