// initialize the locker
application.cacheLocker = CreateObject("component","cacheLocker").init();

// store some arbitrary data
key = application.cacheLocker.store([1,2,3,4]);

// then retrieve the data using the saved key
// throws a CacheException if the key doesn't 'fit'
arbitraryNumbers = application.cacheLocker.retrieve(key);

<cfset params = listToArray(cgi.query_string,"x") />

<cfif arrayLen(params) lt 2>
	<cfthrow message="Input should be like ?[w]x[h]"/>
</cfif>

<cfset width  = params[1] />
<cfset height = params[2] />
<cfset color  = "gray" />

<cfif not (isNumeric(width) and isNumeric(height))/>
	<cfthrow message="Width/Height should be numeric ?100x100">
</cfif>

<cfset image = ImageNew("", width, height,"rgb", color) />
<cfset ImageDrawText(image, "#width# x #height#", 0, 10)>
<cfimage source="#image#" action="writeToBrowser"/>

07 Jan 10 Delving into C#

This year I've decided to really get into C#. My .NET experience is shall at best so aiming to rectify, I picked up C# in Depth and commenced skimming!

Now, I've made my fair share of M$ snide asides, but I'm having a hard time coming to gripes with C#. Everything I run into either "just works" or exceeds my expectations. And the cool features are in fact, quite cool! Color me impressed!

For fun I rewrote a few of my Project Euler Solutions to buff up on the syntax. After I got the semi-colons and brackets all figured out, I moved on to something a little bigger.

I wanted a simple program to run and benchmark my solutions, so I wouldn't have to do as much leg work every time I converted a problem. I figured this would be a simple enough thing to do, and it would provide a good foundation for a future gui application and beginning unit testing.

I wanted to share some particulars that I thought were pretty cool, you can grab the code I'm talking about from the google code repository, and follow along...or something.


Generics, Delegates and Lambdas
Generic Collections provide a data structure that I can access and use just like an array, but also provides methods for dealing with delegates.

Delegates are very similar to closures, blocks, procs, and lambdas like I've worked with in other languages, so the transition was smooth. The lambda syntax was particularly reminiscent of pythonic list comprehensions.

Thanks to delegates, I can turn this:

var matchingTypes = new List<Type>();
foreach(t in CurrentTypes) {
	if(t.IsSubclassOf(parentType) {
		matchingTypes.Add(t);
	}
}
return matchingTypes;

Into this:

return CurrentTypes.FindAll(
	delegate(Type t)
	{
		return t.IsSubclassOf(parentType);
	}
);

And finally, via lambda, to this!

return CurrentTypes.FindAll(
	t => t.IsSubclassOf(parentType)
);

Not too shabby, eh?

Reflection
Most of my programming has been in ColdFusion, JavaScript and Ruby. There's been a little bit of this and a little bit of that peppered in there, particually C and Java while I was at UCF, but for the most part I've enjoyed working with dynamic and/or interpreted languages. Meta-programming is common in these types of languages, but I was surprised and impressed to read up on reflection. In this case, reflection allows me to dynamically detect and run my problems, which makes it easier (and cleaner) for me to add new solutions.

Here's a simplified "ClassMaster" class I use to wrap my reflection calls for listing and creating classes, so you can see what I'm on about:

class ClassMaster
{
	private Assembly CurrentAssembly { get; set; }
	private List<Type> CurrentTypes { get; set; }

	public ClassMaster()
	{
		CurrentAssembly = Assembly.GetExecutingAssembly();
		CurrentTypes = new List<Type>(CurrentAssembly.GetTypes());
	}

	// should probably take arguments to pass thru...somehow
	public Object CreateClass(Type classType)
	{
		return CurrentAssembly.CreateInstance(classType.FullName);
	}

	public List<Type> getTypesByParentClass(Type parentType)
	{
		return CurrentTypes.FindAll(
			t => t.IsSubclassOf(parentType)
		);
	}
}

That's it for now. I'll be looking into LINQ and unit testing in the next couple weeks, and then I'm on to the gui. ASP, SilverLight, and WPF here I come!

Here are those links again:
Release
Latest Version

Tags: c#, meta-programming, project euler