bluebones.net

So basically, there are 4 dimensions:

• Static (expressions have types) vs. dynamic (values have types)
• Strong (values cannot be coerced to other types without a cast) vs. weak (the runtime performs a variety of coercions for convenience)
• Latent (no type declarations) vs. manifest (type declarations)
• Nominal (subtyping relations are declared explicitly) vs. structural (subtyping relations are inferred from the operations available on types)

And you can place most languages on one of these 4 axes, though several support multiple forms of typing:

• Ocaml: static, strong, latent, structural typing
• Haskell: static, strong, latent, structural typing, with nominal typing available via newtype and manifest typing through optional type declarations.
• Erlang: dynamic, strong, latent, structural typing
• Scheme: dynamic, strong, latent, structural typing, with nominal typing available in many object systems.
• Common Lisp: dynamic, strong, latent or manifest typing. Same note about structural vs. nominal typing as Scheme, but nominal subtyping is used more often in practice.
• Python & Ruby: dynamic, strong, latent, structural typing. Nominal subtyping is available via isinstance or Ruby equivalent, but good practice frowns upon it.
• PHP: dynamic, weak, latent, nominal or structural typing. Culture is much friendlier to nominal subtyping than Python or Ruby, but it’s not required.
• Java & C : mostly static, strong, manifest, nominal typing. The casts give you a form of weak-typing when necessary, and C templates are structurally typed.
• C: static, generally weak, manifest, nominal typing.
• Assembly: dynamic, weak, latent, structural typing.

Reddit comment by Nostrademons

Some of us have spent years scraping news sites. Others have spent them downloading government data. Others have spent them grabbing catalog records for books. And each time, in each community, we reinvent the same things over and over again: scripts for doing crawls and notifying us when things are wrong, parsers for converting the data to RDF and XML, visualizers for plotting it on graphs and charts.

It’s time to start sharing our knowledge and our tools. But more than that, it’s time for us to start building a bigger picture together. To write robust crawl harnesses that deal gracefully with errors and notify us when a regexp breaks. To start converting things into common formats and making links between data sets. To build visualizers that will plot numbers on graphs or points on maps, no matter what the source of the input.

We’ve all been helping to build a Web of data for years now. It’s time we acknowledge that and start doing it together.

Oh yes. theinfo.org.

The table with the foreign key in it belongs_to the table that that foreign key references.

The table with the referenced primary key in it has_one or has_many of the table with the foreign key in it.

I will not forget this again!

If you need to use an explicit primary key and not an AUTO_INCREMENT with ActiveRecord I wrote this snippet that has proved very handy:

module ExplicitPrimaryKey
  attr_accessor :pk
  def before_create; self.id = pk; end
end

Then when you call the create method supply :pk => value along with the other values.

ActiveRecord is an ORM solution that grew out of Ruby on Rails. It is entirely separate and can be used outside of Rails.

If you find that ActiveRecord has saved some data starting with three hyphens in your database there IS an explanation. This is a YAML representation of an array.

ActiveRecord is an ORM solution that grew out of Ruby on Rails. It is entirely separate and can be used outside of Rails.

Just spent slightly too long working this out so I thought I’d post this for those with similar requirements.

You need to follow the steps from http://tmtm.org/en/mysql/ruby/. Use ruby extconf.rb --with-mysql-config as the first command.

We have made the OpenSocial API announced by Google on Thursday live on Ning.

It’s an experimental addition, not least because the OpenSocial API is bound to undergo some rapid evolution in the coming weeks. But it does mean that you can install gadgets and write your own gadgets right now.

Further information in Marc’s blog posts.

Very interesting video about the non-text-based programming environment subtext. You can go watch the video, I’ll still be here.

I had to have a quick go at a better version of the Java program that he is improving.

He uses:

    enum Attack { Magic, Melee }
    int damage (Attack attack, bool surprise, int defense) {
        int power;
        switch (attack) {
            case Magic:
                power = 5;
                break;
            case Melee:
                power = 4;
                break;
        }
        int effectiveness = power * (surprise ? 3 : 2);
        switch (attack) {
            case Magic:
                if (effectiveness >= defense)
                    return effectiveness - defense;
                return 0;
            case Melee:
                return (effectiveness / defense) * 2;
        }
    }

Which isn’t actually legal java but it’s close enough.

But how about:

    enum Attack { MAGIC, MELEE }
    int damage (Attack attack, boolean surprise, int defense) {
        int m = (surprise ? 3 : 2);
        if (attack == Attack.MAGIC) {
            return Math.max(5 * m - defense, 0);
        } else {
            return ((4 * m) / defense) * 2;
        }
    }

Which reduces 21 lines to 9. It also gets rid of the main complaint – the “traffic jam” in the middle (but see Update, below).

Or even:

    enum Attack { MAGIC, MELEE }
    int damage (Attack attack, boolean surprise, int defense) {
       int m = (surprise ? 3 : 2);
       return (attack == Attack.MAGIC ? Math.max(5 * m - defense, 0) : ((4 * m) / defense) * 2);
   }

Which is pretty cryptic but only 5 lines.

I think it was a very interesting video and I’m being a bit unfair harping on about this which is kind of irrelevant. But perhaps there’s a lesson in there about picking examples. Conclude what thou wilt.

Would love to have a go with the subtext application.

Update I sent my annoying little examples to Jonathan Edwards who is the creator of subtext. He made some good points in reply (and helped me remove a redundant assertion in my code):

Thanks for your comments. Your revision avoids duplicating the switch by duplicating the multiplication operation. Imagine that single multiplication being instead 10 lines of code. One could of course then push it into a separate method which is called twice, at the cost of separating that code from its uses, and passing as arguments all the dependencies of that code. These are all reasonable trade offs. I am trying to reduce the need to make such trade offs, and keep the code simpler and more compact.

Great talk taken from his new book The Stuff of Thought. I won’t cover the sophisticated and interesting arguments here (read the book!) but here are some nuggets on use of language …

Child to her father:

I don’t want the flat crayons I want the ones that look like an audience.

Groucho Marx classics:

I’ve had a great evening. But this wasn’t it.

If I held you any closer I’d be on the other side of you.

Why does a man with hair on his head have more hair than a man with hairs on his head?

Was the World Trade Centre attack on September 11th 2001 one incident or two? There was a 3.5 billion dollar lawsuit based on the interpretation of a maximum payout of $3.5 billion dollars “per incident”.

One of the reasons detectives suspected Scott Peterson of the murder of his wife was that he referred to her in the past tense before her body was found.

James Garfield‘s assassin’s remark following the death of the President of the United States from complications arising from poor medical care after being shot three months earlier:

The doctors killed him. I just shot him.

The Federal Communications Comission chose not to censure Bono over his remark that the award he was receiving was “really, really fucking brilliant” as it did not refer to a sexual act but was rather used to emphasize. Further legislation was passed as a result of this. Although the legislation goes into graphic detail over what words are not allowed it fails to make illegal the use of fucking as an emphasizing adverb.

That “damn tabernacle” and “damn chalice” are swearing in Quebecois French.

The description of a certain mode of speech as “fuck patois”. And an illustrative tirade from a soldier returning from war:

You fucking mean I’ve fucking come all the way fucking home from the fucking war to my fucking house to find my fucking wife having illicit sexual relations with my fucking neighbour?

The editor of Gourmet magazine challenged one of his journalists to bribe the maître d’s of New York’s finest restaurants $50 to seat him and his partner without reservations. It worked each and every time.