Setting up a IDE to play with GO on Windows
This week Google launched Go, an open source programming language that seems really promising. I've been messing around with the weekly builds but now the Windows build is production ready so here we go.
After downloading and installing the package, the next obvious step was to look for a IDE. There are few choices out there but after trying almost all of them nothing really worked as I've expected. The only one that raised to my expectation was Sublime Text 2 + some 3th party plugins to really have it going.
Ok. So now let's make it happen.
1. Install Go
First thing first. If you didn't already installed it, this is the first step.
Go to http://code.google.com/p/go/downloads/list?q=OpSys-Windows+Type%3DInstaller and download the appropriate package for your machine.
2. Install Sublime Text 2
Sublime Text is a commercial product but it can be used for evaluation purposes. So go and download it from http://www.sublimetext.com/2. Again, choose 32 or 64 bit version.
The last build available on their website already has syntax highlighting for .go files so ... yey
3. Install 3th party libraries and plugins for Sublime Text
This is a lengthy one but without this you just have a new text editor on your computer that can do syntax highlighting to .go files. If that is enough for you then stop here. If not let's get busy.
First you need Sublime Package Control. To install it, open up Sublime Text, press ctrl+` to bring up the console and paste the following:
import urllib2,os; pf='Package Control.sublime-package'; ipp=sublime.installed_packages_path(); os.makedirs(ipp) if not os.path.exists(ipp) else None; urllib2.install_opener(urllib2.build_opener(urllib2.ProxyHandler())); open(os.path.join(ipp,pf),'wb').write(urllib2.urlopen('http://sublime.wbond.net/'+pf.replace(' ','%20')).read()); print 'Please restart Sublime Text to finish installation'
Restart Sublime Text. Now you need to bring up the command palette with ctrl+shift+p and start typing Package Control: Install Package then press return or click on that option to activate it. You will be presented with a new Quick Panel with the list of available packages. Type GoSublime and press return or on its entry to install GoSublime.
Now you have code completion and other IDE-like features provided by GoSublime. There is one more really helpful plugin you should install.
If you have Git installed then open up a cmd, and type
cd %APPDATA%\Sublime Text 2\Packages\
git clone git://github.com/mkrautz/goimport.git GoImport
If you don't have Git then you must download GoImport and extract the zip file in a new folder at %APPDATA%\Sublime Text 2\Packages\GoImport
Now in Sublime Text, go in the menu at Preferences -> Key Bindings - User and between the [] add the following bindings, so your file will look something like this:
[
{ "keys": ["f1"], "command": "prompt_go_import" },
{ "keys": ["f2"], "command": "prompt_go_drop" }
]
This will bind the F1 and F2 keys to popup the go import dialog which will allow you to add from anywhere you are in your file libraries to the top import block.
4. Adding new run/build system
Using Package Control (just like you installed GoSublime) look for and install Go Build. For alternative install informations and other usage and descriptions then go to git.
This will bind F5 key to execute your code and F7 to build your executable and Ctrl-F5 to run your tests.
All done. Now for the final step...
5. Learn GO
- How to write GO code (need to know)
- Tour of GO (kick ass tutorial)
- Effective GO (tips on writing clear, idiomatic Go code)
- Let's learn GO (book)
- Golang nuts mailing list (awesome support)
- Google Search ( 
)
Hope this helps, I don't know myself much more than this yet. If you find something cool please share it with me too. Cheers and happy coding.
JSProfiler – Javascript memory profiler
JsProfiler is a small javascript that I've build to help me identify memory leaks and improve overall performance of some code I was working on.
It works by wrapping all the methods in the given context and keeping track of the number of times they run, how much memory they consume and how long they take to execute.
The results can be viewed real time in a small overlay or you can track specific methods and see the output in the console.
Unfortunately it only works in Google Chrome since Chrome exposes the memory information.
More usage information and download on github
Make a JavaScript getter act both as getter and as a function
So I have a object that exposes a getter to retrieve data after some expensive synchronous computation.
function processData() {
// lots of stuff happening here
return result;
}
return {
get data () {
// some checks happening here
return procesData();
}
}var obj = new MyObject(); var x = obj.data; // this stops things for 2 or 3 seconds // .. carry on
Since this is part of an already used library, is getting pretty hard to change the public interface for backwards compatibility reasons.
The thing is I've added a asynchronous processData method and i want to make that available as well without changing the public methods. The normal thing to do would be to convert the getter into a method called getData() and getDataAsync(callback) but that wouldn't work because it will annoy some people when they see their code isn't working anymore.
The solution couldn't be easier but it took me a while to figure it out and as always, it's sharing time.
function processData() {
// lots of stuff happening here
return result;
}
function processDataAsync(callback) {
if (!arguments.length || arguments.length && typeof arguments[0] !== "function") {
return processData();
}
// lots of stuff happening here but asynchronously
callback(result);
}
processDataAsync.__proto__ = {valueOf : processData};
return {
get data () {
// some checks happening here
return processDataAsync;
}
}var obj = new MyObject(); var x = obj.data; // get data synchronously // .. carry on after 2 seconds var obj = new MyObject(); var x = obj.data(); // still a synchronous call since no callback was given // .. carry on after 2 seconds var obj = new MyObject(); obj.data(function(result) { // get the data here after few seconds without blocking anything } // .. carry on right away
So now the same getter can be used from now on as a asynchronous function if used with parentheses and given a callback or as a simple getter.
Pixel Programming
If you're old enough you may have seen the times when programmers wrote code as optimal as possible given the computers available back then. I remember 3D shooter games that would average 300 - 400 KB in size and you would play countless levels for days. Here's for example a 96 KB 3D shooter game called .kkriger that will leave you breathless.
If you try now to explain people these days that it takes less space to write a 3 minutes HD animated video and music clip than than it takes to store a 32×32 pixel icon they won't believe you. Not now when a plain jpeg image used on some website is > 50KB. So here's a guy called Iñigo Quílez who demonstrates just that using the image analogy. He writes a x86 real mode demo using Photoshop. The entire program is done by creating a 9x9 pixels image, filling each pixels with carefully chosen colors to represent the correct opcodes (who needs compilers, right ?) The image is then saved in a .raw format (no headers) then renames it to a .com file so that Windows recognize it as a executable. The animation is a infinite moving tunnel with a gray colored texture created with an XOR pattern, blurred, and deformed using a plane deformation technique to produce the animation.
This is the "source code" resized 10 times in a png extension
And here's the guy in action proving his mad skills.
Read data directly from base64 without decoding
So here's the catch. You have a binary input you want to mess with in your browser for whatever reason. First problem you encounter is when you load the file. In IE you will have trouble reading a binary string because it uses null terminated strings, and your file will end at the first 0x00 byte found. If you manage to overcome that but trust me it is very CPU intensive. See the source of Read/Load files from ZIP in Javascript post. You will have to create a vbScript that will convert the received AJAX response into an array with decimal values for each byte in the file. Depending on your file size, it will take accordingly (10+ seconds * file KB). For every other browser it works just fine with plain strings.
Okay, one other potential issue may come if you need to receive the data into a JSON string or XML or whatever beside a plain binary file. Then you have to use BASE64 encoding and decode your data into a variable but must keep in mind the first issue with the null characters. My solution to this problem is to create a method to read directly from the BASE64 encoded string at arbitrary locations without decoding the entire thing.
Here's an example of a binary file:
Offset(h)00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F 00000000 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F ............... 00000010 19 84 74 68 69 73 20 69 73 20 61 20 74 65 73 74 ..this is a test
You have 32 bytes in this file, with BASE64 encoding you get a 46 chars length string:
AAECAwQFBgcICQoLDA0ODxmEdGhpcyBpcyBhIHRlc3Q=A usage example:
var data = new Base64Native("AAECAwQFBgcICQoLDA0ODxmEdGhpcyBpcyBhIHRlc3Q="); console.log(data.length); // outputs 32; console.log(data.readBoolean()); // outputs false; - reads a byte and casts it to a boolean value console.log(data.readByte()); // outputs 1; console.log(data.readWord()); // outputs 515; - reads a 16 bit number console.log(data.readInt()); // outputs 67438087; - reads a 32 bit number console.log(data.seek(28)); // moves the pointer to byte 28 (0x1C) console.log(data.readString(data.bytesAvailable())); // outputs 'test'; reads a string from position 28 to the end of the file
And here's the class
var Base64Native = function(data) { var keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=", length = data.length - (data.length / 4) - (data.split(/=/g).length - 1), ptr = 0; function keyIdx(idx) { return keyStr.indexOf(data.charAt(idx)); } function readByte() { if (!(length - ptr)) { throw Error('End of stream!'); } var blockIndex = Math.floor(ptr / 3) * 4, subIndex = ptr++ % 3, ptrChr = blockIndex + subIndex; return !subIndex && ((keyIdx(ptrChr) < < 2) | (keyIdx(ptrChr + 1) >> 4)) || subIndex === 1 && (((keyIdx(ptrChr) & 15) < < 4) | (keyIdx(ptrChr + 1) >> 2)) || ((keyIdx(ptrChr) & 3) < < 6) | keyIdx(ptrChr + 1); } return { /* Returns the available bytes left in the file to read */ bytesAvailable : function() { return length - ptr; }, /* Reads and returns a 8 bit number and increments the position of the index accordingly */ readByte : function() { return readByte(); }, /* Reads and returns a 32 bit number and increments the position of the index accordingly */ readInt : function() { return (readByte() << 24) | (readByte() << 16) | (readByte() << 8) | readByte(); }, /* Reads 1 byte and returns the boolean value of it and increments the position of the index accordingly */ readBoolean : function() { return Boolean(readByte()); }, /* Reads and returns a 16 bit number and increments the position of the index accordingly */ readWord : function() { return readByte() << 8 | readByte() }, /* Reads and returns a string of length 'len' and increments the position of the index accordingly */ readString : function(/*String*/len) { var data = ''; for (var i = 0; i < len; i++) { data += String.fromCharCode(readByte()); } return data; }, /* Moves the index into the file at location newpos */ seek : function(newpos) { ptr = newpos; }, /* Returns the position of the index in the file */ position : function() { return ptr; }, /* The length of the data */ length : length }; };