Comments on: Programming When Clarity Counts

By: Jim N

Jim N — Wed, 24 Feb 2010 03:20:30 +0000

Here’s the full Java code to set up the example (not so succinct as the example its self).

import java.util.ArrayList;
import java.util.List;
 
class Item {
	private double weight;
	Item() {};
	public double getWeight(){ return weight; }
	public Item setWeight(double weight){ this.weight = weight; return this; }
}
 
public class ItemLoop {
 
	@SuppressWarnings("unchecked")
	public static List makeList(double[] numbers) {
		List itemList = new ArrayList();
		for (double nn : numbers) {
			itemList.add(new Item().setWeight(nn));
		}
		return itemList;
	}
 
	public static void main(String args[]) {
 
		double[] numbers = {1.1, 2.2, 3.14159, 4.4};
		List itemList = ItemLoop.makeList(numbers);
 
		double total = 0.0;
 
		for (Item item : itemList) {
			total += item.getWeight();
		}
	}
}

By: Jim N

Jim N — Wed, 24 Feb 2010 03:14:31 +0000

Java 1.5 does vastly improve the situation over 1.4.

double total = 0.0;
 
for (Item item : itemList) {
	total += item.getWeight();
}

Last summer I was maintaining a poorly written Java 1.4 application, so I still vividly recall 1.4′s awkwardness.

By: pat

pat — Sun, 17 May 2009 20:25:44 +0000

Oh, man… Admittedly, I haven’t tried building Boost for about a year and a half, but compiling Boost from source is pain.

By: Abram

Abram — Sun, 17 May 2009 19:56:06 +0000

If, for legacy reasons, you are confined to C++, I’ve found the Boost FOREACH to be a nice bit of syntactic sugar:

double total = 0.0;
BOOST_FOREACH( itemType item, itemList) {
    total += weight( item );
}

By: pat

pat — Mon, 11 May 2009 19:32:14 +0000

I agree the map-in-void-context with side-effects is annoying.

But, coming from Perl 5, I am not jiving with much of the Perl 6 at all. The [+] seems to be floating in there. (Can I use any binary function in its place? Can I only use certain math operators?) Map is a method or property of an array, now? And, we’ve mixed in another meaning for the colon :?

By: Code Clarity Revisited :: nklein software

Code Clarity Revisited :: nklein software — Mon, 11 May 2009 19:19:49 +0000

[...] written in several programming languages. The loop had to sum the weights of each items in a list. Dmitry pointed out a much clearer loop in Lisp using the (loop …) construct. 1(loop for item in item-list [...]

By: chromatic

chromatic — Mon, 11 May 2009 19:19:30 +0000

Aside from the syntax (which non-programmers wouldn’t know), I believe it reads very well. “Total is the sum of all of the weights of every item.”

The Perl 5 map-in-void-context version reads less well, because it relies on a side effect of the map block.

By: pat

pat — Mon, 11 May 2009 15:08:31 +0000

That’s a great presentation. I’m on board with all of it except the Sigils. I know that some believe that Perl’s sigils make things more readable and obviate the need for Hungarian notation. (I am not a big fan of Hungarian notation either.) I think sigils conflate as many things as they clear up. In particular, when one references an item in an array the $ sigil feels contradictory to the square-bracket indexing:

my $item = $array_of_items[ $ii ];

Admittedly, something like the following would be way out of the question:

my $item = $( @array_of_items[ $ii ] );

Further, sigils get flattened entirely to just $ when you’re dealing with references.

Beyond that, I totally agree with the presentation.

Also, that was my first exposure to Moose. Interesting…

By: pat

pat — Mon, 11 May 2009 14:55:21 +0000

I think the Perl 5 map version might be slightly more readable to someone who hasn’t used Perl:

my $total = 0;
map { $total += weight( $_ ) } @list_of_items;

It still leaves something to be desired though for clarity.

By: pat

pat — Mon, 11 May 2009 13:11:23 +0000

Wow. I can see where they are coming from, but that is definitely not code for non-programmers.