In a couple of hours the JavaScript Dublin Group will meet up for the second time. The first meetup was last month, and it was basically a gathering to get to meet other people and talk a bit about organisation.
So this will be the first time for a technical session. Nigel Kelly will be talking about jQuery apps, and I will run a Kata session in JavaScript using Jasmine. I hope people will follow along. We will use the standalone version of Jasmine and the kata chosen for the session is Fizz Buzz.
I came up with the following 4 slides (yeah, want to keep it short!):
The slides will not make much sense on their own, so you better come to the meet up!
This means that I will miss the P2PU SICP study group session on IRC (freenode #sicp room) today at 7pm GTM, 3pm EST, but it's for a good cause, right? :)
Tuesday, June 21, 2011
Saturday, June 18, 2011
SICP -- Starting with the P2PU study group
We have finally started with the SICP study group and I'm delighted to put some time into it. For once, I will focus all my effort and free time to work through and enjoy this fantastic book.
The goal of the group is to finish one section every second week, which gives us 6 weeks for the first chapter. Some people might think that 6 weeks is a lot but to be honest, at least for me, with a full time job, a part time PhD to work on, and all the normal social commitments, it's not that much time. So let's get cracking!
I decided to go back a re-watch the first bunch of MIT SICP lectures as it's been a while since I got around to see them first. I always have this funny and a bit weird feeling when I start watching one because for a moment I feel like I am watching an 80's sitcom or something similar. I'm probably just being silly but it always makes me smile!
The lecture series starts with Harold Abelson ranting a bit about the term Computer Science not being a very good one when it's not a real science, or even about computers. I do agree with him but if you want to know more about the subject you will have to watch it for yourself.
More interesting are his comments about the distinction between declarative or descriptive knowledge and imperative or procedural knowledge. Procedural knowledge or 'Know-How' can be directly applied to a task, whilst declarative knowledge tells us about truth. His example for this is the fact that the square root of a number can be expressed in the form of a mathematic equation(descriptive), compared to a way or algorithm to finding that square root through approximation (imperative).
He also explains that although you can learn most of the LISP language (its rules anyway!) in a short lecture, that does not make you a good user of the language. He compares it to learning the rules of chess and being a good chess player; you need the rules to play, but the rules do not make you any good at it. So you need to embed yourself in the context and the experience, and the techniques to do so are the topic of the course.
In Abelson's words, programming is all about managing complexity, and the techniques in this course will allow you to do so.
The lectures are divided into three main topics which do not correspond to the five sections of my book (my edition is from 1996), but that can be easily correlated, or so I think.
The parts discussed in the lectures are:
- Black-box Abstraction: I guess this will be chapters 1 and 2, building abstractions with procedures/data.
- Conventional Interfaces: I'd say this is chapter 3: Modularity, Objects, and State.
- Metalinguistic Abstractions: This is chapter 4, of the same title.
The fifth chapter of the book about Register Machines does not seem to be in the lectures, but I couldn't tell right now cause I have yet to watch them all.
And that is all for now. I will spend another couple of hours later this evening working through the book and preparing the meeting for tomorrow Sunday at 7pm GMT, 3pm EST. Meetings happen on the #sicp channel on freenode IRC and everybody is welcome!!!
The goal of the group is to finish one section every second week, which gives us 6 weeks for the first chapter. Some people might think that 6 weeks is a lot but to be honest, at least for me, with a full time job, a part time PhD to work on, and all the normal social commitments, it's not that much time. So let's get cracking!
I decided to go back a re-watch the first bunch of MIT SICP lectures as it's been a while since I got around to see them first. I always have this funny and a bit weird feeling when I start watching one because for a moment I feel like I am watching an 80's sitcom or something similar. I'm probably just being silly but it always makes me smile!
The lecture series starts with Harold Abelson ranting a bit about the term Computer Science not being a very good one when it's not a real science, or even about computers. I do agree with him but if you want to know more about the subject you will have to watch it for yourself.
More interesting are his comments about the distinction between declarative or descriptive knowledge and imperative or procedural knowledge. Procedural knowledge or 'Know-How' can be directly applied to a task, whilst declarative knowledge tells us about truth. His example for this is the fact that the square root of a number can be expressed in the form of a mathematic equation(descriptive), compared to a way or algorithm to finding that square root through approximation (imperative).
He also explains that although you can learn most of the LISP language (its rules anyway!) in a short lecture, that does not make you a good user of the language. He compares it to learning the rules of chess and being a good chess player; you need the rules to play, but the rules do not make you any good at it. So you need to embed yourself in the context and the experience, and the techniques to do so are the topic of the course.
In Abelson's words, programming is all about managing complexity, and the techniques in this course will allow you to do so.
The lectures are divided into three main topics which do not correspond to the five sections of my book (my edition is from 1996), but that can be easily correlated, or so I think.
The parts discussed in the lectures are:
- Black-box Abstraction: I guess this will be chapters 1 and 2, building abstractions with procedures/data.
- Conventional Interfaces: I'd say this is chapter 3: Modularity, Objects, and State.
- Metalinguistic Abstractions: This is chapter 4, of the same title.
The fifth chapter of the book about Register Machines does not seem to be in the lectures, but I couldn't tell right now cause I have yet to watch them all.
And that is all for now. I will spend another couple of hours later this evening working through the book and preparing the meeting for tomorrow Sunday at 7pm GMT, 3pm EST. Meetings happen on the #sicp channel on freenode IRC and everybody is welcome!!!
Friday, June 17, 2011
learn, laugh and move on!
There's been a lot going on lately and as a professional procrastinator I couldn't let go the chance of putting off writing a new blog post, but with things going back to normal (hopefully!) it's about time for a bit of reflection.
It's been a very social few weeks, ending May with a double bill: The software craftsmanship conference in Bletchley Park, and a coding day with the chaps of codingday.org here in Dublin.
What can I say about scuk11? it was a great day with fantastic sessions and I got to meet a great bunch of Spaniards in red t-shirts. Happy faces all over... yeah, the bar was already open!
The Dublin event was also fantastic and although it was first thought as a coderetreat, the addition of scientists and their real problems changed the nature of the session itself and made of it a fantastic coding day. The group I was working with got a spinning cube in the browser, with three different lights and three particles lighting up the cube with different colours. Great fun using the Three.js library!
The month of June started with @silverspoon organising hack nights in a café near the city centre, that I sadly missed because I was in Barcelona for a conference. Spain was great, as usual, although it was raining most of the time, but that didn't really have an impact on things such as meeting old friends, the great conversations we had, and of course, the fantastic food!
On Tuesday the 14th we had the first meet up for the SICP study group at P2PU. You can see what happened in the new wiki. This is an open group which basically means that you can join in anytime that suits you. We will meet twice a week for the next couple of months, Tuesdays and Sundays at 7pm GMT, 3pm EST. We are hoping to finish a section every two weeks, including exercises. As chapter one of the book has 3 sections, we are hoping for a 6 week period to be done with it. Wish us luck!!! or even better, join in!!!
Last night the first Ruby Project Night happened in armworks. The space is absolutely great and I want to thank Alan for hosting it. We didn't really know what to expect at first, and after a bit of chat and trying to get the projector going, we started hacking away in a rails 3 gem, something that none of us had done before. We didn't get too far but at least we got it packing and installing fine. As soon as the @theirishpenguin pushes it publicly I will share the link here. It was great to meet a bunch of enthusiastic people and looking forward to meeting them again!
This morning I read this 'Help Wanted' message from @oisin in the ruby Ireland list. If you are looking for contract Ruby work you should definitely get in touch with him. His last talk at ruby Ireland was really interesting.
In the thread he mentions that they like egoless programming which brought me back to the this old post of mine. Weingberg's book is a very recommended read even if as myself, you were not even born when it was written!
An finally, more to look forward to as the first 'technical' meet up of the Javascript Dublin group will be next Tuesday 21st at 7pm. A presentation about jQuery for web apps and a kata with Jasmine are in the menu. Are you really going to miss that???
It's been a very social few weeks, ending May with a double bill: The software craftsmanship conference in Bletchley Park, and a coding day with the chaps of codingday.org here in Dublin.
What can I say about scuk11? it was a great day with fantastic sessions and I got to meet a great bunch of Spaniards in red t-shirts. Happy faces all over... yeah, the bar was already open!
The Dublin event was also fantastic and although it was first thought as a coderetreat, the addition of scientists and their real problems changed the nature of the session itself and made of it a fantastic coding day. The group I was working with got a spinning cube in the browser, with three different lights and three particles lighting up the cube with different colours. Great fun using the Three.js library!
The month of June started with @silverspoon organising hack nights in a café near the city centre, that I sadly missed because I was in Barcelona for a conference. Spain was great, as usual, although it was raining most of the time, but that didn't really have an impact on things such as meeting old friends, the great conversations we had, and of course, the fantastic food!
On Tuesday the 14th we had the first meet up for the SICP study group at P2PU. You can see what happened in the new wiki. This is an open group which basically means that you can join in anytime that suits you. We will meet twice a week for the next couple of months, Tuesdays and Sundays at 7pm GMT, 3pm EST. We are hoping to finish a section every two weeks, including exercises. As chapter one of the book has 3 sections, we are hoping for a 6 week period to be done with it. Wish us luck!!! or even better, join in!!!
Last night the first Ruby Project Night happened in armworks. The space is absolutely great and I want to thank Alan for hosting it. We didn't really know what to expect at first, and after a bit of chat and trying to get the projector going, we started hacking away in a rails 3 gem, something that none of us had done before. We didn't get too far but at least we got it packing and installing fine. As soon as the @theirishpenguin pushes it publicly I will share the link here. It was great to meet a bunch of enthusiastic people and looking forward to meeting them again!
This morning I read this 'Help Wanted' message from @oisin in the ruby Ireland list. If you are looking for contract Ruby work you should definitely get in touch with him. His last talk at ruby Ireland was really interesting.
In the thread he mentions that they like egoless programming which brought me back to the this old post of mine. Weingberg's book is a very recommended read even if as myself, you were not even born when it was written!
An finally, more to look forward to as the first 'technical' meet up of the Javascript Dublin group will be next Tuesday 21st at 7pm. A presentation about jQuery for web apps and a kata with Jasmine are in the menu. Are you really going to miss that???
Thursday, May 19, 2011
Mutant-Java and the KataLonja
Another month and another Kata with the 12meses12katas crowd. This time the kata is in Spanish, and it was created by the agilismo.es guys for the professional track of XGN2011. If anyone needs/wants a translation, do get in touch and I'll produce one. You can find the original version in github: KataLonja.
The Kata is about a Galician chap who wants to make some money by selling Scalops, Octopus, and Spider Crabs in a hired van. We are given a series of prices that markets in different cities will pay for the goods, alongside with distances, transport costs, and depreciation rates for the food, and we need to provide the most interesting route to get a best sale for our intrepid entrepreneur.
As a Galician immigrant myself, this is the simplest kata ever: I would drive the van right into my garage and the goods straight into my fridge; as easy as that!
Sadly this is not going to happen so let's get back to the kata. I'm certainly nowhere near finishing it, I only gave it a first go last night before bed but some cool stuff is already coming up out of it.
As I mentioned in a previous post, I use Katas to refresh some concepts that I haven't seen in a while, or that although I might use them in my day job, I've never gone deeper at them than the old getting the job done.
Last month I choose JavaScript for the bowling kata, and because I started way too late (the last day of the month!), that was the only implementation that I practised on the day. I will try and get this one practised in both Java and JavaScript, starting with the former.
Java has no associative arrays and it's generally accepted that you will use Maps instead. Maps can be very straight forward if you are using an immutable object as the key for your pair, but can get tricky if you decide to use your own class. So that's exactly what I did. It might not be the best fit for the problem at hand, or yield the leaner and cleaner code possible, but no one will have to maintain this code and it's going to be thrown away anyway so better have a bit of fun with it!
So I have created an immutable class for Seafood that I will be using as a key for at least two maps I'm using in other classes. That means overriding equals() and hashcode(), and being careful with state and escaping references to this. But as I said above, the code is nowhere near written, so what's the point of the post you will be asking yourself? I just wanted to share 3 links that have been helpful in digging a bit deeper in the adventure so far. They are:
In them you will find good advice on stuff such as when to create immutable classes and how, uses of immutability including the flyweight pattern, overriding equals() and hashcode(), and a great discussion on how to keep the equals() contract on extended classes, adapted from the book Programming in Scala into Java.
I will be digging a bit more, hopefully in the next couple of days, in topics such as choosing the right map implementation and a couple more things that I want to try (I'd like to write my cucumber step definitions in Ruby instead of Java but I'm not sure I can do that, so will have to find out!).
I also intend to write another post if I ever get to practise the Kata in JavaScript. Comparing both implementations would be cool so let's hope for that!
The Kata is about a Galician chap who wants to make some money by selling Scalops, Octopus, and Spider Crabs in a hired van. We are given a series of prices that markets in different cities will pay for the goods, alongside with distances, transport costs, and depreciation rates for the food, and we need to provide the most interesting route to get a best sale for our intrepid entrepreneur.
As a Galician immigrant myself, this is the simplest kata ever: I would drive the van right into my garage and the goods straight into my fridge; as easy as that!
Sadly this is not going to happen so let's get back to the kata. I'm certainly nowhere near finishing it, I only gave it a first go last night before bed but some cool stuff is already coming up out of it.
As I mentioned in a previous post, I use Katas to refresh some concepts that I haven't seen in a while, or that although I might use them in my day job, I've never gone deeper at them than the old getting the job done.
Last month I choose JavaScript for the bowling kata, and because I started way too late (the last day of the month!), that was the only implementation that I practised on the day. I will try and get this one practised in both Java and JavaScript, starting with the former.
Java has no associative arrays and it's generally accepted that you will use Maps instead. Maps can be very straight forward if you are using an immutable object as the key for your pair, but can get tricky if you decide to use your own class. So that's exactly what I did. It might not be the best fit for the problem at hand, or yield the leaner and cleaner code possible, but no one will have to maintain this code and it's going to be thrown away anyway so better have a bit of fun with it!
So I have created an immutable class for Seafood that I will be using as a key for at least two maps I'm using in other classes. That means overriding equals() and hashcode(), and being careful with state and escaping references to this. But as I said above, the code is nowhere near written, so what's the point of the post you will be asking yourself? I just wanted to share 3 links that have been helpful in digging a bit deeper in the adventure so far. They are:
In them you will find good advice on stuff such as when to create immutable classes and how, uses of immutability including the flyweight pattern, overriding equals() and hashcode(), and a great discussion on how to keep the equals() contract on extended classes, adapted from the book Programming in Scala into Java.
I will be digging a bit more, hopefully in the next couple of days, in topics such as choosing the right map implementation and a couple more things that I want to try (I'd like to write my cucumber step definitions in Ruby instead of Java but I'm not sure I can do that, so will have to find out!).
I also intend to write another post if I ever get to practise the Kata in JavaScript. Comparing both implementations would be cool so let's hope for that!
Monday, April 25, 2011
SICP Study group at P2PU
As mentioned in a previous post, I have decided to learn JavaScript in a serious and deep way, and after following Douglas Crockford's advice on reading the little schemer, it's time for Structure and Interpretation of Computer Programs, also known as SICP.
Due to low numbers in the Anglo-Celt SICP Study Group, we have decided to open the group to the world through the Peer to Peer University (P2PU).
The course is still in draft but so far I've had great feedback from some of the core P2PU community members and I'm hoping that it will go ahead. You can see the draft of the course here: SICP Study group.
[UPDATE]: The course has been moved to the new P2PU site and it is now hosted here and open for application.
As usual, this is a peer to peer, community based effort, and everybody is welcome, even those of you that have read the book already. Assuming the role of mentor can be a fantastic experience, especially in terms of communication and other soft skills that are so important in our field.
To join the course all you need is the motivation to read the book and participate actively in the group, writing blog posts about what you are learning and experiencing, and be willing to share your solutions through github.
As in the previous course, I expect to use Open Wonderland for some of the meetings, but the course can be followed in an asynchronous manner too. If you are interested head to the course and apply (once it's open), or give us a shout if you have any questions!
Due to low numbers in the Anglo-Celt SICP Study Group, we have decided to open the group to the world through the Peer to Peer University (P2PU).
The course is still in draft but so far I've had great feedback from some of the core P2PU community members and I'm hoping that it will go ahead. You can see the draft of the course here: SICP Study group.
[UPDATE]: The course has been moved to the new P2PU site and it is now hosted here and open for application.
As usual, this is a peer to peer, community based effort, and everybody is welcome, even those of you that have read the book already. Assuming the role of mentor can be a fantastic experience, especially in terms of communication and other soft skills that are so important in our field.
To join the course all you need is the motivation to read the book and participate actively in the group, writing blog posts about what you are learning and experiencing, and be willing to share your solutions through github.
As in the previous course, I expect to use Open Wonderland for some of the meetings, but the course can be followed in an asynchronous manner too. If you are interested head to the course and apply (once it's open), or give us a shout if you have any questions!
Wednesday, April 13, 2011
Wonderland Wednesday -- Subsnapshot importer
We've been working on a new Open Wonderland module for exporting and importing parts of a world for the last couple of months. The idea is that when you have a world laid out, you might want to export bits and pieces, or even the whole space, to rebuild it at a later stage or in a different server, or simply as a backup of all your hard work.
Exporting is done by just right clicking in a model or container and choosing Export.
Importing is done by just dragging and dropping the exported file onto the Wonderland client. Easy peasy!
A couple of shots from today's session, in wich we are exporting and importing a bunch of the big fellas.
The module is taking this long to be developed because we are writing all the code as a group, and we only meet about 1 hour a week, so things are moving slowly.
As a result, we are all learning a big deal from each other, especially from Jon, but all of us have worked on parts of the module, which is really cool.
We are even using JUnit to test bits and pieces of the code. The codebase was not written with automated testing in mind, but we are doing all we can to move towards that direction, even if it's just in small doses, and the results are great so far, cause although we are quite far from being able to TDD or test-first even, testing after writing is saving us a lot of time in deploys and server restarts.
Better quality pictures can be found on facebook.
These sessions happen most Wednesdays at 1p.m EST, 6p.m GMT, and everybody is welcome, so hope to see some of you quite soon!
Exporting is done by just right clicking in a model or container and choosing Export.
Importing is done by just dragging and dropping the exported file onto the Wonderland client. Easy peasy!
A couple of shots from today's session, in wich we are exporting and importing a bunch of the big fellas.
 |
| Anyone needs an army? |
 |
| Well behaved big fellas |
 |
| bit to the left... bit to the right... perfect! |
The module is taking this long to be developed because we are writing all the code as a group, and we only meet about 1 hour a week, so things are moving slowly.
As a result, we are all learning a big deal from each other, especially from Jon, but all of us have worked on parts of the module, which is really cool.
We are even using JUnit to test bits and pieces of the code. The codebase was not written with automated testing in mind, but we are doing all we can to move towards that direction, even if it's just in small doses, and the results are great so far, cause although we are quite far from being able to TDD or test-first even, testing after writing is saving us a lot of time in deploys and server restarts.
Also we are not really pairing but 'grouping', and although communication can be harder than in the former, we are having a lot of fun, and that is what really counts!
These are a couple of shots of us working against netbeans and also the space we use, with the wallcard on the far end wall with all the stickies.
 |
| Close up of Netbeans in-world |
 |
| The group writing code, live |
 |
| The WallCard with all the stickies: we are almost there! ...almost! |
These sessions happen most Wednesdays at 1p.m EST, 6p.m GMT, and everybody is welcome, so hope to see some of you quite soon!
Monday, April 11, 2011
about JavaScript, Scheme and History
I've been doing a bit of JavaScript lately and I am shockingly enjoying it. I thought it was going to be a nightmare and a lot of copy+paste but after a good amount of reading and watching talks, I started to like the language. I've been collating bits an pieces of information in the ossdev-ireland wiki, mainly focusing it towards developers that only have to deal with the language in small doses.
Ossdev.org is a place to share experiences that overlap the different open source groups in Ireland. JavaScript and MongoDB are the two topics that seem to be gathering more interest so far, but it's been less that one week since the wiki was installed, so hopefully more topics will start being worked on soon.
The Irish Penguin is the one to blame for all this sharing craziness, and I hope more people get on board in the next couple of weeks.
As usual, following on links and references in talks and tutorials takes you to a thousand other talks and tutorials that you will never have the time to read and watch. I would recommend the fantastic series on Javascript by Douglas Crockford. I especially enjoyed Part I: the early years, cause although it does not contain any code, it is a great lecture in history of computing, and I totally agree that that is an area that we don't handle very well in the profession.
During that talk, Crockford recommends the little schemer as a book that will change the way you think about programming, so I had to get my hands on a copy of it. I have to say that it was a bit difficult to get started with it, because although it seems to be a book targeting children, there is no explanation whatsoever on how to start with the language itself. A bit more digging on the net and I finally downloaded DrScheme, and got it running. Although the site points to a newer version, namely Racket, DrScheme still exists as a package in Ubuntu systems, so that's what I'm using for now.
So this is my first scheme listing ever:
(define atom?
(lambda (x)
(and (not (pair? x)) (not (null? x)))))
(define lat?
(lambda (l)
(cond
((null? l) #t)
((atom? (car l)) (lat? (cdr l)))
(else #f))))
(lat? '(chunky bacon))
(lat? '(chunky (bacon)))
The first call to lat? returns true, and the second false. Let's see how long I can keep up with the parenthesis madness... the plan is to follow on to SICP, but I will have to finish this one first!
Ossdev.org is a place to share experiences that overlap the different open source groups in Ireland. JavaScript and MongoDB are the two topics that seem to be gathering more interest so far, but it's been less that one week since the wiki was installed, so hopefully more topics will start being worked on soon.
The Irish Penguin is the one to blame for all this sharing craziness, and I hope more people get on board in the next couple of weeks.
As usual, following on links and references in talks and tutorials takes you to a thousand other talks and tutorials that you will never have the time to read and watch. I would recommend the fantastic series on Javascript by Douglas Crockford. I especially enjoyed Part I: the early years, cause although it does not contain any code, it is a great lecture in history of computing, and I totally agree that that is an area that we don't handle very well in the profession.
During that talk, Crockford recommends the little schemer as a book that will change the way you think about programming, so I had to get my hands on a copy of it. I have to say that it was a bit difficult to get started with it, because although it seems to be a book targeting children, there is no explanation whatsoever on how to start with the language itself. A bit more digging on the net and I finally downloaded DrScheme, and got it running. Although the site points to a newer version, namely Racket, DrScheme still exists as a package in Ubuntu systems, so that's what I'm using for now.
So this is my first scheme listing ever:
(define atom?
(lambda (x)
(and (not (pair? x)) (not (null? x)))))
(define lat?
(lambda (l)
(cond
((null? l) #t)
((atom? (car l)) (lat? (cdr l)))
(else #f))))
(lat? '(chunky bacon))
(lat? '(chunky (bacon)))
The first call to lat? returns true, and the second false. Let's see how long I can keep up with the parenthesis madness... the plan is to follow on to SICP, but I will have to finish this one first!
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