Blog Archive

List Comprehension

Posted By: Jingyi on April 20, 2010

I have decided to take a look at Erlang to see if we can use it in our products to create scalable, fault-tolerant software.  I am reading the book “Programming Erlang: Software for a Concurrent World”.  Here is an example in the book that uses list comprehension to find all the permutation for a list.

 -module(perm). -export([perm/1]). perm([]) -> [[]]; perm(L) -> [[H | T] || H <- L, T <- perm(L -- [H])]. 

If you have Erlang installed, you can start the shell and run the following test:

 c(perm). %% compile the module perm A = [1, 2, 3]. perm:perm(A). %% will find all the permutation [[1, 2, 3], [1, 3, 2], [2, 1, 3], [2, 3, 1], [3, 1, 2], [3, 2, 1]] 

Now let’s look at the code. Only two lines of code to find…

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Source Control: A Time Machine For Your Source Code

Posted By: Nick Floyd on April 13, 2010

What is source control and why should you use it?

Source control lets you keep every single version of your files. Over time your files change as you make modifications to them. If you’re working on a single file like a document, not tracking those changes is fine, but your source code needs to be tracked even if you are a lone developer. When you are developing an app, sometimes you start down a path that you think will be fruitful, but then you quickly discover that the implementation will not work as well as you thought it would. Using a version control system (VCS) allows you go back to the state of the code before you implemented the feature. Source control is like a time machine for code. If you want to go back, just look at the history and load up the code at that point in time.

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Developer Conference…Lower Price, Same Great Content!

Posted By: Nick Floyd on April 6, 2010

Just when you thought it couldn’t get any better, something like this happens…

We have lowered the price for the Dynamic Church Developer Conference to $49!

Wow…that’s a pretty impressive price. Now that we have the price issue resolved, let’s move on to the content and why you should be in Dallas May 13 - 14.

  • Do you want to learn how to get started with the F1 API? We have a session for that.
  • Do you want to hear about the roadmap for the API and provide feedback that will guide where it goes? We have a session for that.
  • Do you want to dig deeper into the API and find out things you can do with it that you haven’t done yet? We have a session for that.
  • Do you want to hear from our featured keynote speaker who helps companies create valuable…

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