Personal Blogs

Since my last post I've been thinking. Some messing around found me a pattern, a rather nice one for my purposes. Some background. 

I represent, even triangular Boards, as a HashMap of Pegs, some of these Pegs aren't valid. The hashCode() is just...

return (row * 10) + col;

Boards have rows and cols int properties, it doesn't make sense to rotate a Board if these are different. [Reflexion is another matter which I'll tackle later.]

When I started to think about rotation of a Board things got a little complicated. Take a ∏/2 anti-clockwise rotation. The Peg at 02 goes to 40, 05 goes to 10 etc.. Suddenly it hit me!

Take any row

10 11 12 13 14 15 16

Reverse it

16 15 14 13 12 11 10

Transpose the digits of the reversal

61 51 41 31 21 11 1

And map...

10 11 12 13 14 15 16

61 51 41 31 21 11 01

Which is the right answer and is pretty easy to programme. [Pseudo-code, I need to prove this one, I can't see any boundaries to test against.]

((Board.getRows() - Peg.getCol()) * (Peg.getRow() * 10)) + Peg.getRow();

So now I can programme a ∏/2 anti-clockwise rotation, which means I can compose to get the other rotations. Then I can loop through the pegMaps to see if they are equal (in the sense that they can be rotated onto one-another) and I can compare Boards up-to rotation.

I've come across something like this before; with Groups, conjugate cosets, permutations and equivelence. [I really do need to do some work on my Group Theory, because I know that I'm not describing this properly. I see the pattern, but I've forgotten what it's called, and means.]

Still I was right, there's more Groups to Solitaire than we thought.

Is a sodding pain. I will be able to do it, eventually, but for now I'm going to leave it. It's just too fiddly and not much fun.

I can happily save as XML and use an XSLT to get what I need for now.

Really I should be working my way through unit 1 of the topology course, but I can't be bothered with that either.

Three months off have left me unable to motivate myself to do the uncongenial.

[See my previous post]

Creating the XML wasn't difficult, I knew that it wouldn't be. Parsing the thing back will be a bugger.

There's a big bit of me asking why this is should be so. It's not as if XML isn't a standard. Someone should have made this easy. But..

If I bump into a bod on the street and start talking Topology [not there yet, but will be sometime soon ], I'm seen as a benign idiot; I start talking XML and I'm a signed-up-member-of [insert your favourite hate group here].

True, the thing was, and is, used wrongly, but we can say this about any data format, can't we? Morons used it when they shouldn't, it's still better than anything else we have. Or do you fancy openDoc?

Who knows. But it is, funny? One of the major techs that drives the web is named after XML, which it doesn't use. AJAX [Asynchronous Javascipt and XML].

Only a moron loads XML, because you have to fork IE and normal browsers' javascript... [I've tried, if you want the almost working code drop me an email.]

Jings! I've just realized that I need to care not one iota about how others are going to use my stuff. I'm off the leash for once.

So it's going to be XML. Plus.

Today I downloaded the first TMA for the Topology course; the books haven't even been posted yet. Still, come late[-ish] February the thing [the TMA] and its associated PT3 will have to be with my tutor. It's getting serious again.

So, fin de siècle, I've been playing around with my solitaire thingee. I fear that in the near future the poor beast will become neglected. No...that's not right...what's the word that I want? Oh yes, broken, utterly broken.

I've built many a poor beast over the years, all have proved flaky, shoddy, ill-considered and, in-the-end, worthless. For once, this time, I've built something that has some legs [if only in my head]. I know this because I'm having to go out of my way to break the thing; usually this happens by default. On a simple opening.

[It also does some of the things that I meant it to do.]

I don't want to destroy it. But destroy it I shall if I hopelessly-hack-at-it during the few idle moments that I'll have between now and October. Version control is all very well—you can rewind the code. What you can never do is put yourself back into, "knowing what you [meant yourself to be] do[ing]". If you have no documentation, that is.

So I've made a decision: this weekend I'll collate all the pages (bits of paper), that I can scavenge from the scattering of the floors, into a specification, I'll re-do my to-do list, I'll write down my feature requests, I'll make a plan, I'll finish the tests, I'll make sure that the Javadoc makes sense. I'll do what I should have done.

So that, at moments of stress, when maths hurts and I seek the balm of code, I might, do something useful.

Won't, won't and won't.

I hacked away for a couple of hours today until it became obvious that I was flailing hopelessly. So I closed NetBeans and got out a notebook and pencil.

As soon as I did this it all began to come together. This often happens when you're coding—it isn't until you stop that you get an idea of the what it is that you should be doing. Of course, I know this, but I rarely use any of my knowledge.

Since my good idea [see my last post] I've been changing the architecture of the solitaire thingee. Somewhat of a silly thing to do without an entire new spec. When I started the thingee I did have a plan; but when you change said plan? Possibly a good idea to firm-up your concept of the new one? Not something that I did.

My trouble is that I play games [online Go at the present], you're not allowed to try things out, except inside of your own head; what I forget is that I spend rather a lot of my time being physical so that I can do the mental when it comes to games. Still I like to plan in the falible software of my head, despite knowing that this is an idiot thing to do.

That's why fags are important: you have to go outside; where you have to stop doing, and you have to think.

I wrote a failing failing-test.

When I spotted this [because of an un-wanted behaviour] and tried to fix it a firestorm developed. So I stopped coding.

A firestorm [lots of Classes suddenly saying wrong!] is a sure sign that your architecture is gang awry. The worst time to fix this is when you first spot it. Just walk away and try not to think about it, have a drink and make chips...

The strange thing about coding is that it isn't what you do that matters, it's your ability to know when not to do that counts.

Tomorrow, or some other day, I'll come back to this an it will be simple-ish. Today I would have crafted a monster.

We get into groups.

Well, I do.

Today I wanted to stay in, but my wife dragged me out to exercise, "her human right to make-up". We came home cold and penniless. So I did a bit of coding.

I had a problem, which I will explain thus: we have an implementation of a board [which is part of the Model] that we wish to have the View to advertise, and the Controller to know about. Not too difficult you'd think, we use an enum to tell the view what options are available. But then the Controller has to keep up with the changes...

Or does it? And even if it does do we want to hard-code the Controller?

[Board is an Abstract Class, neither the controller nor the Vew should care about what the thing actually is; but as a board maker how do I tell the others that there's a new one? And do they have to alter their code?]

My first-thought was that I could add some methods to an enum, didn't work. But you can wrap a Class around said enum thingees. Throw in some methods and we might be on the right track. 

What I came up with is a class that exposes an enum of what's available and copes with, the inevitable, switch. You send me a switch, I'll send you an instance of what you want if you send me a String.  

public class Boards {

    private enum AvailableBoards {
        ENGLISH,
        FRENCH
    }

    public static Board getBoard(String board) {
        AvailableBoards available = AvailableBoards.valueOf(board);
        Board brd = null;
        switch (available) {
            case ENGLISH:
                brd = new English();
                break;
            case FRENCH:
                brd = new French();
                break;
        }
        return brd;
    }
}

Not finished, indeed I have a burning tree and there are several returns that need to be crafted better.

Still I think that a Class like this [at the top of a package] is a self-documenting boundary for the package. It reminds me of the [rarely-seen] javascript .config.

So I'm trying to be a good boy...

Due to extreme penuary I'm going to have to give up on the drinking and excess for the next couple of weeks. Horrid, but has to be done alas.

So I might as well make the best of a bad job and try to be good in some other areas of life. That other area would be Java.

So tonight I created a load of empty method bodies and rather too many failing tests for my liking. [I think that I have all the classes that I need—we'll see.]

I've also done some reading about MVC and I'm attempting an attempt at it.

This is probably all going to go badly wrong. That's OK, because it doesn't really matter. As long as I have some fun.

[Anyone who has ever coded knows that fun isn't something that you have—you do get something out of it, but it isn't fun.]

dog to it's vomit I find myself skulking back into my old neighbourhood, hanging in my old haunts—I'm coding on the hoof.

True now-a-days I think a wee bit more than I used to; I now think about how I'll eventuallydo it properly. [That might be a conceit.]

I'm going to give myself an out: because I'm so rusty, I may have needed to just code without thought for a while. But, now, @ this moment, when I know that I can code all the parts [or most of them, or I know where to find out where I can, where I know that I can create the thing, where all that's needed is work...] then it's time to step back and write some specifications.

I've written the top level spec.: what I want it to do. Now I have to write the mid-level spec.: how I'm going to implement the top-level. Then it's...

What doesn't help is that my grasshopper mind has become immersed in ciphers.

Most of today has been spent piddling around doing nothing much, however some Java has been written. And that which has been written has convinced me that, at least, some of my madness is achievable.

As ever, with computing, the trick is to break the task down into manageable chunks. So to start with I'm going to write a basic text editor. In real life this would be a stupid proposition [don't re-invent the wheel], but I'm trying to learn here, so I'll let myself off.

An hour or two got me something that I can use. At which point I stopped. Which I'm proud of myself for.

There's a temptation when you're programming to just thrash ahead when things are going well. This has to be resisted—when you see that you can do something then is the time to write the specification. So that [and a visit to B & Q] are on the menu for tomorrow.

I hate writing specifications, and B & Q, but then I hate most of the text editors that I use—they have too many time-consumming features that I never want to use. it would be nice to have a bespoke one.

[Eventually I'll move all this rubbish onto my nonsense, but for now you're going to be stuck with me posting here!]

I opened up NetBeans last night, stared at it blankly for about an hour and then closed it. I couldn't think of anything that I wanted to do. The recent projects were just an accusing glut of failure. I need a new project to mess up.

When I got up this morning I began to think about something—something stupid. As the day wore on it began to look sensible. Naw, sensible isn't the right word, still stupid, but something that I might have fun doing. So here's what I plan to create...

1. A light weight JavaScript library [yeh, that's what the world needs, another bloody JavaScript library!]
2. A JavaScript test suite [rather like JUnit]
3. A Java documentation creator [rather like JavaDoc]
4. A Java compiler for JavaScript
5. A Java IDE for JavaScript
6. A web site to peddle the above

Madness of course, but fun madness. It won't happen, but sometimes stupid is good for the soul.

I have four months before my next course, it's time I went back to where I started to see where I am.