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Well be hacking it up tonight at 6:00PM MST at the Novell Open Source Technology Center. The rough TODO for the night seems to be Tags, Tasks and maybe even a backend to query Beagle. ;) Anyways, if your in the greater Salt Lake City area, come on down! If your a little further away but want to join in anyways, join in on #tomboy!
See you tonight!
Ok, so I was stamping out a recent (quite simple) assignment for a class. The assignment required the separation of each place value in an integer. Since the information came into the program as a string, I stamped out a simple solution using some easy loops and handy methods available in the String class (of the .Net 2.0 class libraries). However, a quick skim over the rubric included 5% for correctly using div and mod to parse out the integer values. I immediately flipped back into my program, then froze for a second..
then another…
then 2 more…
I was completely blanking. I know its a simple task, its just I have become so accustomed to the incredible abundance and availability of a dozen methods for every little task that I blanked for a good minute, just stonewalled. I knew I had written this code before, everyone has done it at least once in some ‘Intro to Programming Theory’ class, and the concept was easy enough, but it just wouldn’t come. Cursing the professor for such a trivial demand, I went and got a cup of coffee.
Upon returning I realized how stupid and petty I was being. While I do often rely on cool class libraries and the methods they provide, I really just have to stop being so self-righteous and realize how likely it was that much of the class would be completely stuck on such a task. We spend so much time today learning about existing technologies and API’s that we forget the core of programming: Problem Solving.
I quickly slapped together the following C# method:
static int[] toIntArray(string input)
{
int i = 0;
int digit;
List<int> ints = new List<int>();
for (int numdigits = input.Length; numdigits > 0; numdigits–)
{digit = Convert.ToInt32(input) / (int)Math.Pow(10.0, (double)(numdigits - 1));
digit = digit % 10;
ints.Add(digit);
i++;
}
return ints.ToArray();
}
In retrospect, its quite simple, I just hope that this was my ‘moment of realization’ and I don’t get so inundated again as to the point where I can’t do the simple stuff on my own anymore.
Ok, so as many of you may have noticed in my last post I’ve taken a real interest in C# 3.0 and its new nifty features. Now, I’m mostly just excited for the simple collection manipulations, but the whole Linq to SQL thing is nagging in the back of my mind. Now while complete CRUD will no doubt take some serious code, simple query support is not that difficult to implement. After following mattwar’s blog series on a generic DB provider for Linq, I decided that I wanted that awesome glory against a lean and mean sqlite db.
So, about an hour or so of messing and meddling I have a few samples working. (The attached zip) Its a Visual Studio 2008 Beta 2 project (I’ll be writing autotools magic for mono later this week) so sorry for that, the code can still be imported into Monodevelop, just the solution/project files won’t work. Anyways, I have tested a smattering of JOIN’s and all sorts of simple selects without issue. However, the elements of sqlite that behave differently tend to do so silently and without complaint, making it harder to be certain that everything is working. However, I’m planning on fleshing out a set of test queries, however, for now I could really just use the help with testing/checking the SQL (as I’m no sqlite Guru).
Known Issues
Anyways, play around, have fun, and note that you need the Sqlite provider for ADO.Net (duh).
I’m looking at db_linq, which is a full (bi-directional, change tracking, general awesome crazyness) solution, this is really just a way to query sqlite db. I might try to add a sqlite provider to db_linq at some point, its just that their system is very different from my implementation, so there wouldn’t be too much shared code. 
Ok, so I’m sure most MS .Net dev’s have already seen these posts far too many times, for the Mono users out there, I have a little treat. While Moonlight and WPF get tons of hype, I think the biggest and most exciting change coming soon to a C# compiler near you is support for lambda expressions, anonymous types, and extension methods.
Now on the whole this doesn’t sound all that exciting, I mean, before a few months ago, I had never really used lambda expressions to accomplish much beyond pass that unit in an intro to CS class. Individually, there’s nothing to jump for joy about, but when used in conjunction, we can produce startlingly clean and readable code.
To demonstrate this I’ve whipped up two examples that I was fiddling with as I read a million tutorials. They aren’t fancy XML or Database providers, just some simple (and quite common in my experience) text parsing tasks that have disproportionately complex code. We will use some of the new C# 3.0 features to make far cleaner and more readable code.
The first example is an exclusion string, or a set of characters that are not allowed in another.
var illegalchars = "abcdefg";
string testString1 = "Kevin";
string testString2 = "hijkmlppp";
The ‘old’ way of checking both strings for one of the illegal chars:
foreach (char c in illegalchars) {
if (testString1.Contains(c) || testString2.Contains(c))
Console.WriteLine("illegal char!");
}
Using awesome new stuff:
if (testString1.Intersect(illegalchars).Any()
|| testString2.Intersect(illegalchars).Any())Console.WriteLine("Linq found it too");
Our next example is ‘exploding’ or splitting a series of values out of a string (CSV and PSV are common examples of this) into an array:
string pipeDelined = "Kevin | McCool | Kubasik";
An old solution might have been (I know we could optimize this, or clean it up, just making a point 
):
List<string> names = new List<string>();
foreach (string s in pipeDelined.Split(‘|’)) {
var ts = s.Trim();if (ts == "") continue;names.Add(ts);
}
var allNames = names.ToArray();
Using our cool new C# 3.0 tools, we can change this to the super-sexy:
var allLinqNames = pipeDelined.Split(‘|’)
.Select(s => s.Trim()).Where(s => s != "").ToArray();
While a hardened child of OOP (via C# and Java) might baulk at the new syntax, I think that it can quickly start to grow on a developer. Moreover, it has the distinct advantage of being unambiguous, and makes reading someone else’s dense code much more fluid.
I really can’t wait for C# 3.0, and not for those flashy API’s, just the simple syntactical sugar that is already making me lazier by the minute.
I’ve been working on and off on a writeup concerning the use of Beagle to build an intelligent ‘rank’ for desktop entities. Or, in short, a Ranking system (not unlike Page Rank or the like) to organize desktop search results by far more than just keyword/date. I know the writing sucks, and its not 100% complete yet. In addition, I don’t have much in terms of code to share (yet).
To summarize (for those lazybones out there) I’m thinking of utilizing fairly universal and constant relationships (Creator, Creation Date, Modification Date(s), Parent/Source, and maybe others) to recurse deep into desktop relationships. By adding relevancy to the root hit for every child it has (logarithmically decreased by recurse iteration) we can have far more accurate desktop search results when querying a simple keyword/phrase. In addition, the children of a hit could often be considered hits themselves, if found in enough ‘root’ hits.
Its a loose and patchy idea, and miles from a realistic implementation, however, thanks to the awesomeness of Lucene, comparing 2 in-index documents for textual relevancy (based on Term Frequency) is not impossible. (I have not considered the performance elements of these comparisons yet, they may be too slow to be realistic without serious optimization)
Anyways, I’m working on it in Google Docs, so you can check out the full document here. I’ll post once I’ve finished my research/planning etc.
Please, share your thoughts! This is in the ‘major brainfart’ stage, so its open to whatever from anyone, I want to hear ideas!
Technorati Tags: beagle, desktop search, lucene, search rank, gnome, mono
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So, while I’m at work, I tend to have some sort of music going on in the background, since I don’t have my whole personal library available (at least, not yet), I’ve become a member of the streaming radio revolution. The obvious choices (for personalized stations, and music you actually want to listen too) are Pandora and Last.fm. I’ve really grown to like both services (although I have a slight preference for last.fm at the moment) the main issue for me is that I have 5,000 songs sitting on my hard drive, all artists I like, so why can’t I get the same awesome intelligent matching among those tracks?
Mirage is an implementation of a Masters thesis on music analysis, the proof of concept code was written in C# (under mono) and targeted at Linux, specifically the Banshee music player. When at home, I love Banshee, I’ve done my fair share of development work on it, and always have a fresh svn checkout of it to see whats new. However, work is on a Windows machine, and I want this cool nifty awesomeness their as well. As a result, I have embarked upon a port of the Mirage library, as well as the creation of an iTunes plugin to make this code useful
Since I figured some other people might be interested in this I made a project at Google Code. There’s not much their yet, just some clumsy stabs at working with Visual Studio (I’m using the 2008 Beta 2… its ‘free’ as in Beer). Anyways, I’ve jotted down some erratic thoughts as to possible goals/design choices.
The current installer should run fine if you have iTunes installed, and parse mp3 and aac files fine. (sorry 32 bit only at the moment) However, I really need to do some more investigation before I’ll know if I’m passing the right data into the library.
Anyways, its cool and all kinds of fun to start using COM If anyone has experience with windows ports and wants to lend a hand or some advice, its all more than welcome.
Technorati Tags: c#, music analysis, smart playlist, iTunes, last.fm , pandora, mono, mirage
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