Self-interest July 2009

self-interest@lists.selflanguage.org

5 participants
8 discussions

Keeping several versions around
by Niko Schwarz 04 Aug '09

04 Aug '09

Hi! I am interested in keeping several versions of code living side by side in the same image. There is an implementation in Smalltalk, but I'd like to know if this could be done more elegantly using Self. The Smalltalk implementation is called Changeboxes, http://scg.unibe.ch/archive/papers/Denk07cChangeboxes.pdf. It essentially works by hooking into the compiler and then, upon every method compilation, NOT pushing the Class onto the stack, but rather a level of indirection which finds the correct version of the class. The idea is essentially the following. Imagine you just built a feature, and it works, let's say you just implemented Exponentiation using a while loop, that just multiplies a number with itself a given number of times. It works. But you find it slow. Now, you fork, and keep the old version around. You change the method, right there, you don't make a new method, you CHANGE the old one. But still, you keep the old one around. And then you run them side by side. The currently active branch might be the sped up algorithm, but you can still access the main trunk, so now you benchmark the two, and see if they yield the same results: [2 raisedTo: 100 ] timeToRunAndResult [[2 raisedTo:100] inBranch: #main] timeToRunAndResult So, how would you implement this version change with only little performance penalty? How does the lookup process work anyway and how can I hook into it? All the best, Niko raisedToThe: anInteger |res| res := 1. anInteger timesRepeat: [ res = res * self] ^ but it is slow. Now you fork, and keep the working version around, both for examination

3 4

Prototypes in Self And JavaScript
by brassplume 31 Jul '09

31 Jul '09

Hi All, I'm playing with the 4.3 Mac Demo.snap image. I'm looking at the tutorial there. I've created lots of slots. I'm seeing how Morphic in that tutorial is similar to the Morphic I've used (but not programmed) in Squeak. It's all pretty cool. One of the things I want to get a grip on is prototypical inheritance as it relates to Self and JavaScript. I understand one lead to the other. I feel on safe ground saying that a lot of people like JavaScript, but mainly use it like C. Or they replicate classical inheritance. Have you seen a book of JavaScript design patterns? Don't bother. I'd really like to say to somebody: "You know, you JS programmer you. Your conception of how to use JS sucks. The reason is you don't understand prototypical inheritance. Here's what you need to know..." And then a light would go on over their head, and they'd use JS the way it's meant to instead of the hack that it usually is. I'm going to read the Wiki page on Prototype-based programming, but anything you could contribute would be great. Chris

3 5

Displaying GIF, PNG and JPG images
by Chris Double 27 Jul '09

27 Jul '09

webBrowser spawns an external program to convert GIF and JPG images to Sun raster format before displaying them. I couldn't find the programs it spawns to install on Linux so I converted the code to use 'convert' from Image Magick. Using this you can display PNG, GIF and JPG images from an imageMorph. With a copied imageMorph as the receiver: setImage: ui2Image copyFromPNGFile: '/path/to/foo.png' Unfortunately this doesn't yet work from the web browser to display images in web pages on Linux due to a crash in an X11 routine. I'll look into that. I put a patch with these changes in the 'webbrowser' branch of git://github.com/doublec/self.git if anyone wants to use it. Chris. -- http://www.bluishcoder.co.nz

1 1

Running Self headless?
by Chris Double 25 Jul '09

25 Jul '09

Is it possible to run the existing Self implementation in a headless environment? For example, running a webserver on a remote machine accessed via ssh. Chris. -- http://www.bluishcoder.co.nz

2 9

Using the arrow keys to move around the world
by Chris Double 25 Jul '09

25 Jul '09

I can use a radarView to move around the world by pressing buttons - is there a way to enable moving around with the arrow keys? I did a quick hack and got something working using normal keys but I couldn't work out how to ask a key down event if it's one of the arrow keys. What I got working was to modify 'handleAndForward:To:' in the handMorph traits. I added code on the keydown check with something like: e metaIsDown && [ e keystrokes includes: 'j' ] ifTrue: [ world moveHand: self InWorldBy: -500@0. ^self. ] I repeated this for the four keys I wanted for up, down, left and right. Ideally I'd like to use the arrow keys though since I'm clashing with some of the editor meta keys. Chris. -- http://www.bluishcoder.co.nz

2 1

Font substitution crash in Linux
by Chris Double 24 Jul '09

24 Jul '09

I sometimes get a crash in the UI running under Linux due to a font not being available. The crash prints in the console: Error: could not load substitute font: -*-times-medium-r-normal--9-*-*-*-*-*-*-*. Receiver is: a x11Globals fontDictionary. UI step failed twice in Self 1(type: worldMorph) -- starting debugger in new world Could not open display "localhost:0.0", error: primitiveFailedError 1. Try Again 2. Try Local Display 3. Give Up [Type the number of your selection] None of the available options allow resuming since the same error continuously occurs. It seems that the requested font is not available in the size of 9 points, The easiest way I can reproduce it is to evaluate something like 'foo' in a shell in the UI, where 'foo' does not exist. The debugger pops up and expanding the stack causes the error. As a temporary workaround I modified the method 'structForFontSpec:WindowCanvas:' in 'traits xFontDictionary' so that when it tries to use the substitute font it specifically uses a size of '10' - one I know that exists on my system. - substituteName: (fullNameFor: x11Globals scalableFont times Size: fSpec size). + substituteName: (fullNameFor: x11Globals scalableFont times Size: 10). This stops the crash and lets me use the debugger and other tools (The inspectors in the Smalltalk application), Chris. -- http://www.bluishcoder.co.nz

2 1

IRC Socket example
by Chris Double 23 Jul '09

23 Jul '09

I'm playing around with Sockets in Self and put together a little IRC bot object. It's pretty basic but is usable to talk to an IRC server. The code is here: http://www.bluishcoder.co.nz/self/ircBot.self Copy it to 'objects/applications' and load with: bootstrap read: 'ircBot' from: 'applications'. It creates an 'ircBot' object in globals. You can copy this to connect a server. There are slots for the server name, port and nickname. These default to 'irc.freenode,net', 6667, and 'selfbot' respectively. For testing I make a copy of this, and keep the outliner on the screen. I create an evaluator for that object so I can send messages to it. To use, first send 'connect'. This will connect to the server. >From there you can use 'join: #channel' to join a channel and 'say: msg To: channel' to talk in the channel. The server messages are stored in a 'lines' slot as a list. It was my first time building objects using the Self UI and finding methods in existing objects using the search features. I was dubious as to how productive it would be but it worked well. Chris. -- http://www.bluishcoder.co.nz

1 0

Linux Socket Support
by Chris Double 22 Jul '09

22 Jul '09

Do sockets work in the Linux VM? When trying methods like openTCPHost I get an error about the slot socketConstants not existing. I notice this is defined in 'traits unixFile osVariants bsd' so I copied this slot into the linux variants. Unfortunately any attempt to call openTCPHost from then fails with ECONNREFUSED. Attempting to track this down in the debugger is proving difficult due to other issues I'm having with fonts. Has anyone been able to use the socket routines? Chris. -- http://www.bluishcoder.co.nz

2 4

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

1999

1998

1997

1996

1995

1994

1993

1992

1991

1990

Self-interest July 2009