Gregor's World

Comic 2011-03-31

2011-03-31T10:37:00.001-07:00

The Four Duties of Coding

2011-03-23T21:26:00.000-07:00

"Concision," a noun form of the adjective "concise" makes for a handy one-word summary of what we are seeking in the artifacts we produce from our work as software developers. Lets look at a definition of concise:

giving a lot of information clearly and in a few words; brief but comprehensive.

(from Mac OS X Leopard Dictionary.app)

That sounds great, but what does it really mean, in real-world application to our work?

The "four C's" of coding are all aimed at making your code concise. They are, in priority order:

Correct
Complete
Clear
Compact

The gold standard for code is to meet all four of these simultaneously, but we would not be doing engineering if there were not trade-offs, at least at intermediate points along the way in development if not in the final product.

The First Duty is to write code that is Correct. That can mean meeting a specification for semantics or for performance or for robustness in the face of bad inputs. Of course, the way to achieve Correct code could include a mix of refining the specification where it is ambiguous, negotiating requirements to make them more amenable to implementation, and of course the particulars of the approach and implementation. These same four C's could equally be applied to the specification as to the code that is produced in response to it.

The Second Duty is to write code that is Complete. In a way, this is an extension of the dictum to write Correct code, since if the code is incomplete, it cannot be correct, but the distinction is we should strive to write smaller bits of correct code with higher priority, and fill in and integrate it into a larger whole to achieve completeness as a secondary objective. Well-constructed code should be composable into a larger whole to achieve a well-constructed whole.

The Third Duty is to write code that is Clear. Code is written by one human to tell other humans across space and time what it is intended that a computer should do. Code should be written in a way that respects its nature as a write-once, read-many (and possibly modify-many) artifact. As long as Correctness and Completeness have been achieved, one should strive for code that is as clear as possible within those constraints.

The Fourth Duty is to write code that is Compact. If there are multiple representations that satisfy the first three Duties with equal or nearly equal success, then selecting for the representation that is more Compact will help keep incidental complexity as low as possible. Just as Complete can be thought of as subsumed within Correct, Compact can be thought of as subsumed within Clear, but is called out separately precisely to assert that its priority is strictly lower than overall Clearness. Do not optimize for compactness at the expense of clarity.

mordant

2009-09-07T12:00:00.000-07:00

According to Merriam-Webster's Online Dictionary: “biting and caustic in thought, manner, or style : incisive <a mordant wit>”

milksop

2009-08-31T12:00:00.000-07:00

According to Dictionary.com: “a weak or ineffectual person.” According to The Oxford Dictionary of English Etymology: “milksop orig. SOP dipped in milk, (hence) one who is fed on such food, young infant, (transf.) effeminate fellow” Also: milquetoast

horology

2009-08-24T12:00:00.000-07:00

(No, I'm not going to give a hint for this one!) The science of measuring time.

hondo

2009-08-17T12:00:00.000-07:00

According to Wikipedia, “The lariat has a small reinforced loop at one end, called a honda or hondo, through which the rope passes to form a loop.”

encomium

2009-08-10T12:00:00.000-07:00

According to Merriam-Webster's Online Dictionary: “glowing and warmly enthusiastic praise ; also : an expression of this.” Definitely not to be confused with meconium!

dysteleology

2009-08-03T12:00:00.000-07:00

The doctrine of purposelessness in nature See also: Wikipedia.

dubnium

2009-07-29T12:00:00.000-07:00

HINT: It is not "former President George W. Bush's favorite element". One of the elements (Symbol Db; atomic number 105). See also: Wolfram|Alpha"

docent

2009-07-20T12:00:00.000-07:00

A teacher or lecturer at some universities who is not a regular faculty member.

curtilage

2009-07-13T12:00:00.000-07:00

The enclosed area immediately surrounding a house or dwelling. See also: Wikipedia

atelier

2009-07-06T12:00:00.000-07:00

Per Wikipedia: “an artist's studio or workroom.”

bavardage

2009-06-29T12:00:00.000-07:00

Babble, jargon. According to Free online ditionary: ”Much talking; prattle; chatter.“

zeitgeist

2009-06-22T12:00:00.000-07:00

From the German: "spirit of the times".

brickbat

2009-06-15T12:00:00.000-07:00

An unfavorable remark; criticism.

nefandous

2009-06-08T12:00:00.000-07:00

Per Wiktionary: “Unspeakable, appalling”.

polymath

2009-06-01T12:00:00.000-07:00

A person of broad knowledge.

ignis fatuus

2009-05-25T12:00:00.000-07:00

A Will-o'-the-wisp. Recorded in English from the mid 16th century, the phrase is modern Latin, literally ‘foolish fire’ (because of its erratic movement).

abjure

2009-05-18T12:00:00.000-07:00

To renounce under oath; forswear.

Scala custom syntax: "after"

2009-02-11T10:34:00.000-08:00

I've run into this pattern a few times where I want to return the value of some expression, but I also need to do some side-effect between evaluating the expression and returning its value. For example, putting the result into a cache. Or, setting some additional state in a constructed object. The normal way of doing this involves putting the value of the expression into a temporary variable, performing whatever other operations are needed and then returning the value of the temporary. That is fine but it turns into at least three lines of code and some cases are so simple you might wish you could do it all on one line and not bother naming a temporary.

I recently gave a presentation on "Sampling Scala" and ended up developing a Scala custom syntax addition to handle it. At the Scala BASE meeting at Googleplex last night, Jorge Ortiz was showing a Lift Chat server example and it had this piece of code:

  private val server = {
    val ret = ChatServer.server
    ret ! ChatServerAdd(this)
    ret
  }

Which demonstrates the situation. I'd much rather write that:

  private val server = ChatServer.server after { _ ! ChatServerAdd(this) }

Here's the way to implement after:

object After {
  implicit def any2After[A](value: A) = new After(value)

  class After[A](val value: A) {
    def after[B](f: A => B) : A = { f(value); value }
  }
}

And, here is another example of using it:

import collection.mutable.Map
import After._

val cache = Map[Int, Int]()
  
def foo(x : Int) : Int = {
  val y = // ...

  return y after { cache(x) = _ } // like finally, with an arg
}

Capesize / capsize

2008-12-15T09:56:00.001-08:00

I just read the Financial Times article Rates for shipping charters rebound and came across the term "capesize" for very large container ships.

That is close enough to "capsize" to be broken, especially since the term comes from the need for such ships to pass Cape Horn because they cannot pass the Suez Canal (although for low draft vessels it is possible now). The WikiPedia article says of Cape Horn "... the waters around the cape are particularly hazardous, owing to strong winds, large waves, strong currents and icebergs; these dangers have made it notorious as a sailors' graveyard."

Smart Beep "Blind Date" Commercial

2008-11-30T12:00:00.000-08:00

I came across this a while back and I'm a little ashamed to admit it still makes me laugh.

I hope you enjoy it too...

Dickinson Family Favorite Sloppy Joe Recipe

2008-09-19T13:23:00.001-07:00

Yum! This is one of my all-time favorites.

2 lb. hamburger
Salt and pepper to taste
1 large onion, chopped (or dried minced onions to taste, say 2-4 Tbsp.)
12 oz catsup
2 Tbsp. sugar
2 Tbsp. dry mustard
2 Tbsp. vinegar

In skillet, cook hamburger with 1 cup water and seasonings until meat starts to turn color. Drain grease. Add remaining ingredients and simmer for 1 hour, or longer. A croc pot works great for the final phase.

— Alice Crandall

Blog moved to Blogger.com!

2008-09-07T15:45:00.000-07:00

The move to wordpress.com didn't quite get me what I wanted. So, I've moved everything to blogger.com now. I just finished moving all the Gregor's Word of the Week entries over by hand (ouch).

“Parking Lot Protocol”

2008-09-02T12:00:00.000-07:00

There are rules for keeping safe in a parking lot, especially when one is a small child. So, when I taught my children to stay together, stay near an adult, hold hands, not run, watch for cars, not walk to close to cars, and so on, I called it the “Parking Lot Protocol”. Now all I have to do when we are about to enter the parking lot and I want to get them focussed on safety I just call out “Parking Lot Protocol” and everybody knows what to do.