The document discusses the idea that code "cries" when it is difficult to understand and modify. It suggests reframing "code smells" as issues where the code is trying to communicate something but is not being understood. The author argues that software becomes harder to work with over time because developers try to force their own designs rather than letting the code evolve naturally through an iterative process. Developers are encouraged to let go of preconceived designs and diagrams in order to build code in a more organic, timeless way.

1. When Code Cries
Cory Foy
@cory_foy
foyc@coryfoy.com
http://www.coryfoy.com
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
Reading from Timeless Way. Then: All of us here are technologists in some way. We desire to
build things that people will use. Living software. But if you look at our industry, the fruit of
our labors is not living software. The majority of software out there has a common attribute.
It is:
1

2. Bad Code
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
Bad Code is the bane of the software industry. Why is it that, over time, code becomes harder
and harder to work with - and how can we prevent ours from ending up with the same fate?
To answer that, perhaps we should start with identifying what quality code is. So, is this
quality code?
2

3. Is this quality code?
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
Why do we like Easy to Change code? Because it is a lower cognitive burden. Because writing
code is hard enough, as we’ll see.
3

4. Is this quality code?
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
Why do we like Easy to Change code? Because it is a lower cognitive burden. Because writing
code is hard enough, as we’ll see.
3

5. Cognitively Undemanding
Where we want our
software
Context
Embedded
Context
Reduced
Modifying Software we
wrote
@cory_foy
Modifying Software we
didn’t write
Cognitively Demanding
foyc@coryfoy.com
Thursday, November 14, 13
We want code that is in the upper right quadrant. But, if we’re lucky to be modifying our own
code, it’s in the lower left. Worse case, we don’t even have the context, so it’s in the lower
right. Now, if we have tests, that helps increase the context. But when we don’t, we can end
up with code that looks like
4

6. Cognitively Undemanding
Where we want our
software
Context
Embedded
Context
Reduced
Modifying Software we
wrote
@cory_foy
Modifying Software we
didn’t write
Cognitively Demanding
foyc@coryfoy.com
Thursday, November 14, 13
We want code that is in the upper right quadrant. But, if we’re lucky to be modifying our own
code, it’s in the lower left. Worse case, we don’t even have the context, so it’s in the lower
right. Now, if we have tests, that helps increase the context. But when we don’t, we can end
up with code that looks like
4

7. Cognitively Undemanding
Where we want our
software
Context
Embedded
Context
Reduced
Modifying Software we
wrote
@cory_foy
Modifying Software we
didn’t write
Cognitively Demanding
foyc@coryfoy.com
Thursday, November 14, 13
We want code that is in the upper right quadrant. But, if we’re lucky to be modifying our own
code, it’s in the lower left. Worse case, we don’t even have the context, so it’s in the lower
right. Now, if we have tests, that helps increase the context. But when we don’t, we can end
up with code that looks like
4

8. Cognitively Undemanding
Where we want our
software
Context
Embedded
Context
Reduced
Modifying Software we
wrote
@cory_foy
Modifying Software we
didn’t write
Cognitively Demanding
foyc@coryfoy.com
Thursday, November 14, 13
We want code that is in the upper right quadrant. But, if we’re lucky to be modifying our own
code, it’s in the lower left. Worse case, we don’t even have the context, so it’s in the lower
right. Now, if we have tests, that helps increase the context. But when we don’t, we can end
up with code that looks like
4

9. @cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
5
Code that isn’t a joy. That is anti-joy. Code which is frustrating to be around. This is not code
that is alive - this is code which has problems. And these problems - we tend to name them
something. When we see something not right in code, what do we say?

10. @cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
5
Code that isn’t a joy. That is anti-joy. Code which is frustrating to be around. This is not code
that is alive - this is code which has problems. And these problems - we tend to name them
something. When we see something not right in code, what do we say?

11. @cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
5
Code that isn’t a joy. That is anti-joy. Code which is frustrating to be around. This is not code
that is alive - this is code which has problems. And these problems - we tend to name them
something. When we see something not right in code, what do we say?

12. @cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
5
Code that isn’t a joy. That is anti-joy. Code which is frustrating to be around. This is not code
that is alive - this is code which has problems. And these problems - we tend to name them
something. When we see something not right in code, what do we say?

13. @cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
5
Code that isn’t a joy. That is anti-joy. Code which is frustrating to be around. This is not code
that is alive - this is code which has problems. And these problems - we tend to name them
something. When we see something not right in code, what do we say?

14. @cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
5
Code that isn’t a joy. That is anti-joy. Code which is frustrating to be around. This is not code
that is alive - this is code which has problems. And these problems - we tend to name them
something. When we see something not right in code, what do we say?

15. @cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
5
Code that isn’t a joy. That is anti-joy. Code which is frustrating to be around. This is not code
that is alive - this is code which has problems. And these problems - we tend to name them
something. When we see something not right in code, what do we say?

16. @cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
5
Code that isn’t a joy. That is anti-joy. Code which is frustrating to be around. This is not code
that is alive - this is code which has problems. And these problems - we tend to name them
something. When we see something not right in code, what do we say?

17. Code Smells
@cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
6
Right - “Smelly Code”. But what I’d like to do today is reframe the discussion slightly. Instead
of telling our code that it smells, let’s recognize something else - our code is trying to talk to
us.

18. Code Talks
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
And imagine trying to talk to someone about something important - say, the building is on
fire - and them not understanding your strange gestures and telling you you are smelly.
Would that make you happy? It doesn’t make our code happy. And if I can take some poetic
license, I’d even say that code cries
7

19. Code Cries
@cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
8
And our code cries not because it is smelly, but because no one understands what it is trying
to say. It’s trying to point out what it wants to do, what is important, and how to use it. And it
isn’t happy about that! Too often we try to force what we want, what we think is best.

20. Code Cries
Because No One
Understands What It Is
Saying
@cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
8
And our code cries not because it is smelly, but because no one understands what it is trying
to say. It’s trying to point out what it wants to do, what is important, and how to use it. And it
isn’t happy about that! Too often we try to force what we want, what we think is best.

21. “...we have so far beset ourselves with rules, and
concepts, and ideas...that we have become afraid of
what will happen naturally, and convinced that we must
work within a “system” and with “methods” [or] our
surroundings will come tumbling down in chaos.”
Christopher Alexander - “The Timeless Way of Building”
@cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
9
We turn to our UML and architecture diagrams and design documents, trying to brute force a
system that will work, afraid that if we don’t - chaos. But nature *dictates* an iterative design
- one where the best path is not only discovered, but continually chosen. We literally can not
build software any other way.

22. @cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
10
This is a map of the Mississippi River in the United States. What’s special about it is that it is all of the routes the
river has run through the years. We create a design. We settle down, build a house, have a family. But the code
doesn't want that. It has plans beyond our design. And if we don't listen to those plans, our days will become filled
with holding off the impending - and inevitable - change (http://www.adammandelman.net/tag/harold-fisk/)

23. @cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
11
For example, in 2011, the Mississippi River tried to change course, I believe to the Orange
area. And it normally would have - except for the millions of dollars the Army Corp of
Engineers spent to erect dams, flood farm fields and otherwise keep it on the course best for
us - not for it. But trying to brute force design into nature’s iterative process isn’t the only
problem. (10k next)

24. @cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
12
There’s a common figure that is given to developers about what it takes to become great in
software. Does anyone know that number? <Click> This is the number of hours to “master” a
skill. But as much as we tout this, we don’t really act like this is important. People new to
software either get this

25. Ten Thousand Hours
@cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
12
There’s a common figure that is given to developers about what it takes to become great in
software. Does anyone know that number? <Click> This is the number of hours to “master” a
skill. But as much as we tout this, we don’t really act like this is important. People new to
software either get this

26. bloody
@cory_foy
Thursday, November 14, 13
So, confusion and frustration, or this
foyc@coryfoy.com
13

27. @cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
Empty promises! (Beaker story). Can you imagine learning C++ in 24 hours? Well, you might
be able to learn syntax, but building great software isn’t just about learning syntax. Or
diagrams. At the start of the talk, I quoted Alexander talking about a Timeless Way of
Building - and that this way - this timeless way - is the only way buildings - or software that are alive can be built. And if we go right to the kernel of that way, he says
14

28. @cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
Empty promises! (Beaker story). Can you imagine learning C++ in 24 hours? Well, you might
be able to learn syntax, but building great software isn’t just about learning syntax. Or
diagrams. At the start of the talk, I quoted Alexander talking about a Timeless Way of
Building - and that this way - this timeless way - is the only way buildings - or software that are alive can be built. And if we go right to the kernel of that way, he says
14

29. @cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
Empty promises! (Beaker story). Can you imagine learning C++ in 24 hours? Well, you might
be able to learn syntax, but building great software isn’t just about learning syntax. Or
diagrams. At the start of the talk, I quoted Alexander talking about a Timeless Way of
Building - and that this way - this timeless way - is the only way buildings - or software that are alive can be built. And if we go right to the kernel of that way, he says
14

30. @cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
Empty promises! (Beaker story). Can you imagine learning C++ in 24 hours? Well, you might
be able to learn syntax, but building great software isn’t just about learning syntax. Or
diagrams. At the start of the talk, I quoted Alexander talking about a Timeless Way of
Building - and that this way - this timeless way - is the only way buildings - or software that are alive can be built. And if we go right to the kernel of that way, he says
14

31. “To make a building {alive}...the
builder must let go of all his
willful images, and start with a
void...At this stage the building’s
life will come directly from your
language”
Christopher Alexander - “The Timeless Way of Building”
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
So for us to be able to build great software, we have to be willing to let go of the diagrams.
Of the syntax. Of the “Point A, Point B, flow”. And let go of the fear
15

32. “You are able to do this only
when you no longer fear that
nothing will happen”
Christopher Alexander - “The Timeless Way of Building”
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
of the fear that if we let go, nothing will happen. Or chaos will happen. So, how do we get to
the point where we feel comfortable enough to let go. And, more importantly, how do we
teach others to get to that point? I think that the way that we do that is by recognizing that
the heart of programming isn’t code, but communication. That’s why we call them
programming languages. And we can learn a lot from how people learn languages to help us
along our ten thousand hour path to get to the point where we can build alive systems by
letting go
16

33. Imperative Programming
Functional Programming
Logic Programming
Dynamic Typing
Static Typing
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
This first is the understanding of how languages/paradigms affect our viewpoints. Roman
Jakobson points out “Languages differ...must convey vs what they may convey”. “dinner with
a neighbor last night”, doesn’t reveal if it was a male or female. But if I said in German, I
would be obliged to (Nachbar vs Nachbarin). Functional: context of reduction of terms.
Imperative: statement of the process, and logic: statement of the result. Static: abstractions
sooner, dynamic: abstraction to be held off
17

34. Coding Standards Define Dialects
@cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
18
The second is that even within languages we have dialects. We have to agree on what that
common dialect is going to be. This is traditionally the essence of coding standards - what is
our agreed upon dialect?

35. Coding Standards Define Dialects
@cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
18
The second is that even within languages we have dialects. We have to agree on what that
common dialect is going to be. This is traditionally the essence of coding standards - what is
our agreed upon dialect?

36. Coding Standards Define Dialects
@cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
18
The second is that even within languages we have dialects. We have to agree on what that
common dialect is going to be. This is traditionally the essence of coding standards - what is
our agreed upon dialect?

37. BICS
CALP
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
The third is that the way we approach and learn languages is somewhat haphazard. You only
need to look at any programming language book to see they all do them differently. But the
process of learning a natural language is well known, and standardized regardless of the
language. We can apply a similar framework to develop the skills we need to listen and
understand our code
19

38. BICS
CALP
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
The third is that the way we approach and learn languages is somewhat haphazard. You only
need to look at any programming language book to see they all do them differently. But the
process of learning a natural language is well known, and standardized regardless of the
language. We can apply a similar framework to develop the skills we need to listen and
understand our code
19

39. BICS
Context
Embedded
Context
Reduced
CALP
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
The third is that the way we approach and learn languages is somewhat haphazard. You only
need to look at any programming language book to see they all do them differently. But the
process of learning a natural language is well known, and standardized regardless of the
language. We can apply a similar framework to develop the skills we need to listen and
understand our code
19

40. Cognitively Undemanding
- Copying from the board
- Reading a Map
- Face to Face Conversation
- Selecting food in the
lunchroom
BICS
Context
Embedded
Context
Reduced
CALP
@cory_foy
Cognitively Demanding
foyc@coryfoy.com
Thursday, November 14, 13
The third is that the way we approach and learn languages is somewhat haphazard. You only
need to look at any programming language book to see they all do them differently. But the
process of learning a natural language is well known, and standardized regardless of the
language. We can apply a similar framework to develop the skills we need to listen and
understand our code
19

41. Cognitively Undemanding
- Copying from the board
- Reading a Map
- Face to Face Conversation
- Selecting food in the
lunchroom
BICS
- Following a class schedule
- Telephone Conversation
- Oral Presentations
- Getting an absence excuse
Context
Embedded
Context
Reduced
CALP
@cory_foy
Cognitively Demanding
foyc@coryfoy.com
Thursday, November 14, 13
The third is that the way we approach and learn languages is somewhat haphazard. You only
need to look at any programming language book to see they all do them differently. But the
process of learning a natural language is well known, and standardized regardless of the
language. We can apply a similar framework to develop the skills we need to listen and
understand our code
19

42. Cognitively Undemanding
- Copying from the board
- Reading a Map
- Face to Face Conversation
- Selecting food in the
lunchroom
BICS
- Following a class schedule
- Telephone Conversation
- Oral Presentations
- Getting an absence excuse
Context
Embedded
Context
Reduced
- Demonstrations
- Basic Math
Computations
- Science Experiments
CALP
@cory_foy
Cognitively Demanding
foyc@coryfoy.com
Thursday, November 14, 13
The third is that the way we approach and learn languages is somewhat haphazard. You only
need to look at any programming language book to see they all do them differently. But the
process of learning a natural language is well known, and standardized regardless of the
language. We can apply a similar framework to develop the skills we need to listen and
understand our code
19

43. Cognitively Undemanding
- Copying from the board
- Reading a Map
- Face to Face Conversation
- Selecting food in the
lunchroom
BICS
- Following a class schedule
- Telephone Conversation
- Oral Presentations
- Getting an absence excuse
Context
Embedded
Context
Reduced
- Demonstrations
- Basic Math
Computations
- Science Experiments
- Standardized Tests
- Math Concepts and
Applications
- Listening to a Lecture
CALP
@cory_foy
Cognitively Demanding
foyc@coryfoy.com
Thursday, November 14, 13
The third is that the way we approach and learn languages is somewhat haphazard. You only
need to look at any programming language book to see they all do them differently. But the
process of learning a natural language is well known, and standardized regardless of the
language. We can apply a similar framework to develop the skills we need to listen and
understand our code
19

44. Cognitively Undemanding
BICS
Context
Embedded
Context
Reduced
CALP
@cory_foy
Cognitively Demanding
foyc@coryfoy.com
Thursday, November 14, 13
This framework, which I’m calling the “Foy-Z” model (with great irreverence), looks like this.
We need to start by providing context. Katas provide a container to operate with in. Koans
provide language specific nuances. Principles help us analyze our code in a higher context
way, while patterns forces us to think about our overall goals. So let’s look at these a little
more.
20

45. Foy-Z
Cognitively Undemanding
BICS
Context
Embedded
Context
Reduced
CALP
@cory_foy
Cognitively Demanding
foyc@coryfoy.com
Thursday, November 14, 13
This framework, which I’m calling the “Foy-Z” model (with great irreverence), looks like this.
We need to start by providing context. Katas provide a container to operate with in. Koans
provide language specific nuances. Principles help us analyze our code in a higher context
way, while patterns forces us to think about our overall goals. So let’s look at these a little
more.
20

46. Foy-Z
Cognitively Undemanding
BICS
Katas
Context
Embedded
Context
Reduced
CALP
@cory_foy
Cognitively Demanding
foyc@coryfoy.com
Thursday, November 14, 13
This framework, which I’m calling the “Foy-Z” model (with great irreverence), looks like this.
We need to start by providing context. Katas provide a container to operate with in. Koans
provide language specific nuances. Principles help us analyze our code in a higher context
way, while patterns forces us to think about our overall goals. So let’s look at these a little
more.
20

47. Foy-Z
Cognitively Undemanding
BICS
Katas
Koans
Context
Embedded
Context
Reduced
CALP
@cory_foy
Cognitively Demanding
foyc@coryfoy.com
Thursday, November 14, 13
This framework, which I’m calling the “Foy-Z” model (with great irreverence), looks like this.
We need to start by providing context. Katas provide a container to operate with in. Koans
provide language specific nuances. Principles help us analyze our code in a higher context
way, while patterns forces us to think about our overall goals. So let’s look at these a little
more.
20

48. Foy-Z
Cognitively Undemanding
BICS
Katas
Koans
Context
Embedded
Context
Reduced
Principles
CALP
@cory_foy
Cognitively Demanding
foyc@coryfoy.com
Thursday, November 14, 13
This framework, which I’m calling the “Foy-Z” model (with great irreverence), looks like this.
We need to start by providing context. Katas provide a container to operate with in. Koans
provide language specific nuances. Principles help us analyze our code in a higher context
way, while patterns forces us to think about our overall goals. So let’s look at these a little
more.
20

49. Foy-Z
Cognitively Undemanding
BICS
Katas
Koans
Context
Embedded
Context
Reduced
Principles
Patterns
CALP
@cory_foy
Cognitively Demanding
foyc@coryfoy.com
Thursday, November 14, 13
This framework, which I’m calling the “Foy-Z” model (with great irreverence), looks like this.
We need to start by providing context. Katas provide a container to operate with in. Koans
provide language specific nuances. Principles help us analyze our code in a higher context
way, while patterns forces us to think about our overall goals. So let’s look at these a little
more.
20

50. Katas
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
Let’s start with Katas. First described in the software world by Pragmatic Dave Thomas, they
offer the ability to practice without the solution being the cognitive challenge. In short, they
allow developers to practice varying externally motivated viewpoints.
21

51. Conway’s Game of Life
- Infinite Grid of Cells
- Each Cell has two states - alive or dead
- Interacts with neighbors in a well known way
http://en.wikipedia.org/wiki/Conway%27s_Game_of_Life
@cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
22

52. Conway’s Game of Life
- Infinite Grid of Cells
- Each Cell has two states - alive or dead
- Interacts with neighbors in a well known way
http://en.wikipedia.org/wiki/Conway%27s_Game_of_Life
@cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
22

53. Conway’s Game of Life
- Infinite Grid of Cells
- Each Cell has two states - alive or dead
- Interacts with neighbors in a well known way
http://en.wikipedia.org/wiki/Conway%27s_Game_of_Life
@cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
22

54. Conway’s Game of Life
- Infinite Grid of Cells
- Each Cell has two states - alive or dead
- Interacts with neighbors in a well known way
http://en.wikipedia.org/wiki/Conway%27s_Game_of_Life
@cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
22

55. Conway’s Game of Life - If Statement
@cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
23

56. Conway’s Game of Life - If Statement
@cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
23

57. Conway’s Game of Life - No Conditional
@cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
24

58. Foy-Z
Cognitively Undemanding
BICS
Katas
Context
Embedded
Context
Reduced
CALP
@cory_foy
Cognitively Demanding
foyc@coryfoy.com
Thursday, November 14, 13
So Katas allow us to not focus on solving the problem, but instead using the problem to
explore the space of viewpoints. The context is very high - we cognitively understand the
problem, so we can focus on practice. But at some point we need more - and that’s where
25

59. Foy-Z
Cognitively Undemanding
BICS
Katas
Koans
Context
Embedded
Context
Reduced
CALP
@cory_foy
Cognitively Demanding
foyc@coryfoy.com
Thursday, November 14, 13
So Katas allow us to not focus on solving the problem, but instead using the problem to
explore the space of viewpoints. The context is very high - we cognitively understand the
problem, so we can focus on practice. But at some point we need more - and that’s where
25

60. Koans
@cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
26
Koans come in. Koans provide language-specific nuances - the grammar if you will. They
tend to be language specific, but lower context. It’s like practicing nouns and verbs - great to
do, but much better if you have some context to put them in. For example (next Edgecase
Koans)

61. https://github.com/neo/ruby_koans
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
one of the more famous software Koans was by Edgecase (now called Neo). You can see in
the structure it was very specific to the Ruby language - arrays, assets, blocks, etc.
27

62. Ruby Koans Asserts
@cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
28

63. Ruby Koans Arrays
@cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
29

64. Foy-Z
Cognitively Undemanding
BICS
Katas
Koans
Context
Embedded
Context
Reduced
CALP
@cory_foy
Cognitively Demanding
foyc@coryfoy.com
Thursday, November 14, 13
So far, we’ve stayed in the BICS realm. BUT! We’ve learned something interesting. The Koans
taught us Ruby array management, and we needed that for our exercise, so let’s revisit the
Katas
30

65. Conway’s Game of Life - With Map
@cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
31

66. Conway’s Game of Life - With Map
@cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
31

67. Foy-Z
Cognitively Undemanding
BICS
Katas
Koans
Context
Embedded
Context
Reduced
CALP
@cory_foy
Cognitively Demanding
foyc@coryfoy.com
Thursday, November 14, 13
At this point, we have enough basic skills that we can begin to get into cognitively
demanding work. We have the context, and the grammar, but we don’t know the optimal
ways to apply the grammar. That’s where coding principles come in to play
32

68. Foy-Z
Cognitively Undemanding
BICS
Katas
Koans
Context
Embedded
Context
Reduced
Principles
CALP
@cory_foy
Cognitively Demanding
foyc@coryfoy.com
Thursday, November 14, 13
At this point, we have enough basic skills that we can begin to get into cognitively
demanding work. We have the context, and the grammar, but we don’t know the optimal
ways to apply the grammar. That’s where coding principles come in to play
32

69. Principles
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
Our principles guide us in how we apply our code within the context of what we’re writing.
33

70. SOLID Principles
Do we have
duplication
(implementation or
conceptual)?
Single
responsibilities?
LoD violations?
LSP violations?
@cory_foy
Thursday, November 14, 13
Transition to patterns
foyc@coryfoy.com
34

71. 4 Rules of Simple Design
Does this code express all of the ideas
we want to express?
@cory_foy
Thursday, November 14, 13
Patterns. 4 Rules of Simple Design. Fowler. SOLID
foyc@coryfoy.com
35

72. 4 Rules of Simple Design
Does this code express all of the ideas
we want to express?
@cory_foy
Thursday, November 14, 13
Patterns. 4 Rules of Simple Design. Fowler. SOLID
foyc@coryfoy.com
35

73. 4 Rules of Simple Design
Does this code express all of the ideas
we want to express?
@cory_foy
Thursday, November 14, 13
Patterns. 4 Rules of Simple Design. Fowler. SOLID
foyc@coryfoy.com
35

74. 4 Rules of Simple Design
Does this code express all of the ideas
we want to express?
Are there concepts from our domain that can be
expressed?
@cory_foy
Thursday, November 14, 13
Patterns. 4 Rules of Simple Design. Fowler. SOLID
foyc@coryfoy.com
35

75. 4 Rules of Simple Design
Does this code express all of the ideas
we want to express?
Are there concepts from our domain that can be
expressed?
@cory_foy
Thursday, November 14, 13
Patterns. 4 Rules of Simple Design. Fowler. SOLID
foyc@coryfoy.com
35

76. Fowler’s Perspectives (from UML Distilled)
Are we operating at
the right level Conceptual,
Specification or
Implementation?
@cory_foy
Thursday, November 14, 13
Patterns. 4 Rules of Simple Design. Fowler. SOLID
foyc@coryfoy.com
36

77. Fowler’s Perspectives (from UML Distilled)
Are we operating at
the right level Conceptual,
Specification or
Implementation?
@cory_foy
Thursday, November 14, 13
Patterns. 4 Rules of Simple Design. Fowler. SOLID
foyc@coryfoy.com
36

78. Foy-Z
Cognitively Undemanding
BICS
Katas
Koans
Context
Embedded
Context
Reduced
Principles
CALP
@cory_foy
Cognitively Demanding
foyc@coryfoy.com
Thursday, November 14, 13
At this point, we have enough basic skills that we can begin to get into cognitively
demanding work. As I mentioned earlier, Design Patterns
37

79. Foy-Z
Cognitively Undemanding
BICS
Katas
Koans
Context
Embedded
Context
Reduced
Principles
Patterns
CALP
@cory_foy
Cognitively Demanding
foyc@coryfoy.com
Thursday, November 14, 13
At this point, we have enough basic skills that we can begin to get into cognitively
demanding work. As I mentioned earlier, Design Patterns
37

80. Patterns
@cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
38
Design Patterns provide a guide for the forces encountered. What does that mean? We have a
tendency to think of Design Patterns as recipes to make our code look a certain way. But

81. @cory_foy
Thursday, November 14, 13
Patterns are something else.
foyc@coryfoy.com
39

82. Naming something the name of a pattern
does not make it that pattern
@cory_foy
Thursday, November 14, 13
Patterns are something else.
foyc@coryfoy.com
39

83. Naming something the name of a pattern
does not make it that pattern
Putting patterns in our code does not
make our code good
@cory_foy
Thursday, November 14, 13
Patterns are something else.
foyc@coryfoy.com
39

84. Porch Swing
@cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
40

85. Porch Swing
@cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
40

86. Swimming Pool
@cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
41

87. Swimming Pool
@cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
41

88. Hedge Trimmer
@cory_foy
Thursday, November 14, 13
Not a pattern, but a death trap (next GoF Book / Structure of Patterns)
foyc@coryfoy.com
42

89. Hedge Trimmer
@cory_foy
Thursday, November 14, 13
Not a pattern, but a death trap (next GoF Book / Structure of Patterns)
foyc@coryfoy.com
42

90. • Pattern Name
• Intent
• Also Known As
• Motivation / Forces
• Applicability
• Structure
• Participants
• Collaboration
• Consequences
• Implementation
• Sample Code
• Known Uses
• Related Patterns
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
The GoF Book wasn’t a beginners guide. It was Erich’s PhD Thesis. Patterns are designed to
put into form the forces you may run into while building code. What does that mean?
43

91. Server
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
Let’s imagine a mobile application to upload pictures. So what forces are at play here? We
know we have to associate multiple pictures to data. Data can have new types added, which
need to be available on all other phones. The phone needs to be able to send the pictures to
the server, as well as send and receive data updates. And deal with offline conditions.
44

92. - Countries
- Products
- Locations
Server
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
Let’s imagine a mobile application to upload pictures. So what forces are at play here? We
know we have to associate multiple pictures to data. Data can have new types added, which
need to be available on all other phones. The phone needs to be able to send the pictures to
the server, as well as send and receive data updates. And deal with offline conditions.
44

93. - Countries
- Products
- Locations
- Send Data
- Receive Data
Server
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
Let’s imagine a mobile application to upload pictures. So what forces are at play here? We
know we have to associate multiple pictures to data. Data can have new types added, which
need to be available on all other phones. The phone needs to be able to send the pictures to
the server, as well as send and receive data updates. And deal with offline conditions.
44

94. Multiple
Pictures
- Countries
- Products
- Locations
- Send Data
- Receive Data
Server
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
Let’s imagine a mobile application to upload pictures. So what forces are at play here? We
know we have to associate multiple pictures to data. Data can have new types added, which
need to be available on all other phones. The phone needs to be able to send the pictures to
the server, as well as send and receive data updates. And deal with offline conditions.
44

95. Multiple
Pictures
- Countries
- Products
- Locations
Send
Pictures
- Send Data
- Receive Data
Server
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
Let’s imagine a mobile application to upload pictures. So what forces are at play here? We
know we have to associate multiple pictures to data. Data can have new types added, which
need to be available on all other phones. The phone needs to be able to send the pictures to
the server, as well as send and receive data updates. And deal with offline conditions.
44

96. Multiple
Pictures
- Countries
- Products
- Locations
Send
Pictures
- Send Data
- Receive Data
Server
@cory_foy
Storage Options
foyc@coryfoy.com
Thursday, November 14, 13
Let’s imagine a mobile application to upload pictures. So what forces are at play here? We
know we have to associate multiple pictures to data. Data can have new types added, which
need to be available on all other phones. The phone needs to be able to send the pictures to
the server, as well as send and receive data updates. And deal with offline conditions.
44

97. Offline
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
One way is by knowing the forces at play and comparing them to previous events. For
example, the phone (or server) could be offline. What can we do if we are offline?
45

98. Offline
Not allow send
@cory_foy
Queue items to send
foyc@coryfoy.com
Thursday, November 14, 13
One way is by knowing the forces at play and comparing them to previous events. For
example, the phone (or server) could be offline. What can we do if we are offline?
45

99. Offline
Not allow send
Automatically
@cory_foy
Queue items to send
Manually
foyc@coryfoy.com
Thursday, November 14, 13
One way is by knowing the forces at play and comparing them to previous events. For
example, the phone (or server) could be offline. What can we do if we are offline?
45

100. Offline
Not allow send
Automatically
Queue items to send
Manually
Forces:
- User has to remember to
send
- User can’t do other tasks
until sent
- User has to send each one
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
One way is by knowing the forces at play and comparing them to previous events. For
example, the phone (or server) could be offline. What can we do if we are offline?
45

101. Offline
Not allow send
Automatically
Forces:
- Store multiple requests
- Schedule to run them
- Handle failed requests
- Allow user to see
status
@cory_foy
Queue items to send
Manually
Forces:
- User has to remember to
send
- User can’t do other tasks
until sent
- User has to send each one
foyc@coryfoy.com
Thursday, November 14, 13
One way is by knowing the forces at play and comparing them to previous events. For
example, the phone (or server) could be offline. What can we do if we are offline?
45

102. http://www.soapatterns.org/asynchronous_queuing.php
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
So the patterns we choose are a result of the forces we are trying to resolve - the forces
inherent in the solution itself.
46

103. Foy-Z
Cognitively Undemanding
BICS
Context
Embedded
Context
Reduced
CALP
@cory_foy
Cognitively Demanding
foyc@coryfoy.com
Thursday, November 14, 13
So now that we’ve got a framework on how to get the point of understanding, now what?
Well, our code is getting happier, because
47

104. @cory_foy
Thursday, November 14, 13
we’ve begun addressing some of the key issues in being able to listen to it.
foyc@coryfoy.com
48

105. We don’t
understand the
language
@cory_foy
Thursday, November 14, 13
we’ve begun addressing some of the key issues in being able to listen to it.
foyc@coryfoy.com
48

106. We don’t
understand the
language
We don’t have
common context
@cory_foy
Thursday, November 14, 13
we’ve begun addressing some of the key issues in being able to listen to it.
foyc@coryfoy.com
48

107. We don’t
understand the
language
We don’t have
common context
We don’t know
the grammar
@cory_foy
Thursday, November 14, 13
we’ve begun addressing some of the key issues in being able to listen to it.
foyc@coryfoy.com
48

108. We don’t
understand the
language
We don’t have
common context
We don’t know
the grammar
We don’t know
how to apply the
grammar
@cory_foy
Thursday, November 14, 13
we’ve begun addressing some of the key issues in being able to listen to it.
foyc@coryfoy.com
48

109. We don’t
understand the
language
We don’t have
common context
We don’t know
how to apply the
grammar
We don’t know
the grammar
We don’t know
what’s
appropriate
@cory_foy
Thursday, November 14, 13
we’ve begun addressing some of the key issues in being able to listen to it.
foyc@coryfoy.com
48

110. http://www.flickr.com/photos/jakeandlindsay/5524669257
@cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
49
So how to we apply it? How do we use that to now let go? First, diagrams aren’t bad. There’s
nothing wrong with sketching out a plan. But, “No plan survives first contact with the enemy”.
So pay attention to the forces more than the plan.

111. http://www.soapatterns.org/asynchronous_queuing.php
@cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
50
For example, looking at this pattern again, notice the impacts. We may say to ourselves, we
want an Aysnc Queue, so fine, be on the lookout for that. But don’t blindly just shove an
async queue in. Watch for your code to tell you it needs it. (This also applies to databases and
many other things we “Know we need”)

112. http://marchoeijmans.blogspot.com/2013/03/test-driven-development-tdd.html
(Although I disagree with the article)
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
Second: If you haven’t done TDD, or aren’t doing it, I’d highly recommend spending some
time with Katas trying it out. What I find powerful is that it makes no qualms about your
design. Don’t write a design, and then write tests to prove you are writing your design. Let
the tests guide you. See what design emerges from them.
51

113. @cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
Third: Technical Vision. In a team environment, you want to make sure you all are on the
same page. Traditionally we’ve built software bottom up. But this doesn’t give us an
opportunity to learn. “Tracer Bullets”
52

114. Database
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
Third: Technical Vision. In a team environment, you want to make sure you all are on the
same page. Traditionally we’ve built software bottom up. But this doesn’t give us an
opportunity to learn. “Tracer Bullets”
52

115. Stored Procedures
Database
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
Third: Technical Vision. In a team environment, you want to make sure you all are on the
same page. Traditionally we’ve built software bottom up. But this doesn’t give us an
opportunity to learn. “Tracer Bullets”
52

116. Service Layer
Stored Procedures
Database
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
Third: Technical Vision. In a team environment, you want to make sure you all are on the
same page. Traditionally we’ve built software bottom up. But this doesn’t give us an
opportunity to learn. “Tracer Bullets”
52

117. API Layer
Service Layer
Stored Procedures
Database
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
Third: Technical Vision. In a team environment, you want to make sure you all are on the
same page. Traditionally we’ve built software bottom up. But this doesn’t give us an
opportunity to learn. “Tracer Bullets”
52

118. Front End Layer
API Layer
Service Layer
Stored Procedures
Database
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
Third: Technical Vision. In a team environment, you want to make sure you all are on the
same page. Traditionally we’ve built software bottom up. But this doesn’t give us an
opportunity to learn. “Tracer Bullets”
52

119. Front End Layer
API Layer
Service Layer
Stored Procedures
Database
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
Third: Technical Vision. In a team environment, you want to make sure you all are on the
same page. Traditionally we’ve built software bottom up. But this doesn’t give us an
opportunity to learn. “Tracer Bullets”
52

120. Front End Layer
API Layer
Service Layer
Stored Procedures
Database
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
Third: Technical Vision. In a team environment, you want to make sure you all are on the
same page. Traditionally we’ve built software bottom up. But this doesn’t give us an
opportunity to learn. “Tracer Bullets”
52

121. Front End Layer
API Layer
Service Layer
Stored Procedures
Database
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
Third: Technical Vision. In a team environment, you want to make sure you all are on the
same page. Traditionally we’ve built software bottom up. But this doesn’t give us an
opportunity to learn. “Tracer Bullets”
52

122. Front End Layer
API Layer
Service Layer
Stored Procedures
Database
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
Third: Technical Vision. In a team environment, you want to make sure you all are on the
same page. Traditionally we’ve built software bottom up. But this doesn’t give us an
opportunity to learn. “Tracer Bullets”
52

123. Front End Layer
API Layer
Service Layer
Stored Procedures
Database
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
Third: Technical Vision. In a team environment, you want to make sure you all are on the
same page. Traditionally we’ve built software bottom up. But this doesn’t give us an
opportunity to learn. “Tracer Bullets”
52

124. Front End Layer
API Layer
Service Layer
Stored Procedures
Database
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
There’s nothing wrong with a vision. And as you work on slices, you can check against the
overall vision to see if you are on the path you expected, or if your vision needs to change.
Not the code, but the vision.
53

125. Vision
Front End Layer
API Layer
Service Layer
Stored Procedures
Database
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
There’s nothing wrong with a vision. And as you work on slices, you can check against the
overall vision to see if you are on the path you expected, or if your vision needs to change.
Not the code, but the vision.
53

126. Vision
Front End Layer
API Layer
Service Layer
Stored Procedures
Database
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
There’s nothing wrong with a vision. And as you work on slices, you can check against the
overall vision to see if you are on the path you expected, or if your vision needs to change.
Not the code, but the vision.
53

127. Vision
Front End Layer
API Layer
Service Layer
Stored Procedures
Database
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
There’s nothing wrong with a vision. And as you work on slices, you can check against the
overall vision to see if you are on the path you expected, or if your vision needs to change.
Not the code, but the vision.
53

128. Pay attention to the forces
Let the code (and tests!) guide your design
Develop a vision, but use it as a guide, not a whipping post
@cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
54
These things together, along with the solid understanding of the different paradigms and
approaches are going to get you to the point where you can let go of the “willful images” and
start really listening to your code. And when you listen to your code

129. @cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
you end up with happy code. And when you don’t, you end up with unhappy code, baffled at
why you are even bothering to build it if you aren’t going to listen.
55

130. if coder_listens?
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
you end up with happy code. And when you don’t, you end up with unhappy code, baffled at
why you are even bothering to build it if you aren’t going to listen.
55

131. if coder_listens?
puts “:-)”
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
you end up with happy code. And when you don’t, you end up with unhappy code, baffled at
why you are even bothering to build it if you aren’t going to listen.
55

132. if coder_listens?
puts “:-)”
else
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
you end up with happy code. And when you don’t, you end up with unhappy code, baffled at
why you are even bothering to build it if you aren’t going to listen.
55

133. if coder_listens?
puts “:-)”
else
puts “:`-(“
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
you end up with happy code. And when you don’t, you end up with unhappy code, baffled at
why you are even bothering to build it if you aren’t going to listen.
55

134. if coder_listens?
puts “:-)”
else
puts “:`-(“
end
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
you end up with happy code. And when you don’t, you end up with unhappy code, baffled at
why you are even bothering to build it if you aren’t going to listen.
55

135. if coder_listens?
puts “:-)”
else
puts “:`-(“
end
@cory_foy
foyc@coryfoy.com
Thursday, November 14, 13
you end up with happy code. And when you don’t, you end up with unhappy code, baffled at
why you are even bothering to build it if you aren’t going to listen.
55

136. Cory Foy
(@cory_foy)
foyc@coryfoy.com
www.coryfoy.com
@cory_foy
Thursday, November 14, 13
foyc@coryfoy.com
56