Tags: , , , , , , , , , | Categories: Event Posted by bsstahl on 6/23/2017 8:10 AM | Comments (0)

The slide deck for my talk “A Developer’s Survey of AI Techniques” can be found below, while the demo code can be found on GitHub.



The talk explores some of the different techniques used to create Artificial Intelligences using the example of a Chutes & Ladders game.  Various AIs are developed using different strategies for playing a variant of the game, using different techniques for deciding where on the game board to move.

If you would like me to deliver this talk, or any of my talks, at your User Group or Conference, please contact me.

I really enjoy working with .NET Core.  I like the fact that my code is portable to many platforms and that the footprint is so much smaller than with traditional .NET applications.  Unfortunately, the tooling has not quite reached the level that we expect from a Microsoft finished product (which it isn’t – yet). As a result, there are some additional actions we need to take when setting up our solutions in Visual Studio 2015 to allow us to unit test our code properly.  The following are the steps that I currently take to setup and test a .NET Core library using XUnit and Moq.  I know that a number of these steps will be done for us, or at least made much easier, by the tooling in the coming months, either by Visual Studio 2017, or by enhancements to the Visual Studio 2015 environments.

  1. Create the library to be tested in Visual Studio 2015
    1. File > New Project > .Net Core > Class Library
    2. Notice that this project is created in a solution folder called ‘src’
  2. Create a solution folder named ‘test’ to hold our test projects
    1. Right-click on the Solution > Add > New Solution Folder
  3. Add a new console application to the test folder as our test project
    1. Right-click on the ‘test’ folder > Add > New Project > .Net Core > Console Application
  4. Add a reference to the library being tested in the test project
    1. Right-click on the test project > Add > Reference > Select the library to be tested
  5. Install packages needed for unit testing from NuGet to the test project
    1. Right-click on the test project > Manage NuGet Packages > Browse
    2. Install ‘xunit’ as our unit test runner
      1. The current version for .Net Core is ‘2.2.0-beta4-build3444’
    3. Install ‘dotnet-test-xunit’ to integrate xunit with the Visual Studio test tools
      1. The current version for .Net Core is ‘2.2.0-preview2-build1029’
    4. Install ‘Moq’ as our mocking library
      1. The current version for .Net Core is ‘4.6.38-alpha’
  6. Edit the project.json of the test library
    1. Change the “EmitEntryPoint” option to false
    2. Add “testrunner” : “xunit” node

Some other optional steps include:

  • Install the ‘Microsoft.CodeCoverage’ package from NuGet to enable the code coverage tooling
  • Install the ‘Microsoft.Extension.DependencyInjection’ package from NuGet to enable DI
  • Install the ‘TestHelperExtensions’ package from NuGet to add extensions that assist with writing good unit tests
  • Add any additional runtimes that might be needed. Some options are:
    • win10-x86
    • win10-x64
    • win7-x86
    • win7-x64
  • Set ‘Run tests after build’ in Visual Studio so tests run automatically

There will likely be better ways to do many of these things shortly, but if you know a better way now, please let me know via Twitter.

One of the techniques I recommend highly in my Simplify Your API talk is the use of extension methods to hide the complexity of lower-level API functionality.  A good example of a place to use this methodology came-up last night in a great Reflection talk by Jeremy Clark (Twitter, Blog) at the NorthWest Valley .NET User Group


Jeremy was demonstrating a method that would spin-through an assembly and load all classes within that assembly that implemented a particular interface.  The syntax to do the checks on each type were just a bit more obtuse than Jeremy would have liked them to be.  As we left that talk, I only half-jokingly told Jeremy that I was going to write him an extension method to make that activity simpler.  Being a man of my word, I present the code below to do just that.

Tags: , , , , , , | Categories: Event Posted by bsstahl on 10/6/2016 6:20 AM | Comments (0)

The next two months are packed with tons of great technical events that I am really looking forward to.  Below are some of the events that I am involved with and will be attending between now and the end of November. I hope to run into you at these events.  If you see me, please don’t hesitate to say “hi”. I do love to talk tech.

Desert Code Camp – Phoenix AZ – October 8th 2016

Desert Code Camp makes its triumphant return from hiatus this weekend at Chandler-Gilbert Community College in the south-east valley.  I will be delivering my talk, “A Developer’s Guide to Finding Optimal Solutions” which is an introduction to combinatorial optimization designed specifically for software developers, at 9:45 am in room CHO-110.

IT/DevConnections – Las Vegas NV– October 10th-13th 2016

One of my favorite large conferences of the year is IT/DevConnections in Las Vegas.  This year marks my 4th attendance at this event, the 2nd as a speaker. I will be delivering the talk, “Dynamic Optimization – One Algorithm All Programmers Should Know”, a programmer’s introduction to Dynamic Programming, at 2:15 pm on October 13th in Brislecone 2 at the Aria Resort.

Atlanta Code Camp – Atlanta GA – October 15th 2016

This year marks my 2nd attendance at the Atlanta Code Camp.  My 1st experience there, last year when I presented on Dynamic Programming, was a big part of the inspiration for drilling deeper into the topic of combinatorial optimization. As such, I return to Atlanta this year with my new talk on the subject, “A Developer’s Guide to Finding Optimal Solutions”.

NWVDNUG & SEVDNUG – Phoenix AZ – Oct 26th and 27th

It is not yet confirmed as of this publication but I have a really great, internationally renown speaker lined-up for the Northwest Valley and Southeast Valley .NET User Groups this month.  Final arrangements are currently being made so keep an eye on meetup.com for each group for the details to be published as soon as they are finalized.

SoCalCodeCamp – Los Angeles CA, November 12th – 13th 2016

I have attended many instances of the Southern California Code camp, but this will only be my 2nd time at the Los Angeles incarnation of this event.  My 1st time there, last year, I was struck by the old-school beauty of the old school campus and facilities at USC when I presented my talk on Dynamic Programming.  This year, I will follow that up with my new, more general overview on the subject of finding optimal solutions.

NWVDNUG & SEVDNUG – Phoenix AZ – Nov 16th and 17th

Our good friend Jeremy Clark (blog, twitter) makes his annual tour of the Valley’s .NET User Groups to talk to us, once again, about many of the things you need to know about .NET and Software Engineering to make your development better. Jeremy will give a different talk each night so be sure to sign-up at the meetup sites and come to both meetings.

Tags: , , , , , | Categories: Development Posted by bsstahl on 2/27/2016 7:44 PM | Comments (0)

I had an experience this past week that reminded me of both the importance of continuing the Test Driven Development process beyond the initial development phases of a application's life-cycle, and that not all developers have yet fully grasped the concepts behind Test Driven Development.

One of the development teams I work with had a bug come-up in a bit of complex logic that I designed. I was asked to pair-up with one of the developers to help figure out the bug since he had already spent several hours looking at it. When I asked him to show me the tests that were failing, there weren't any. The bug was for a situation that we hadn't anticipated during initial development (a common occurrence) and he had not yet setup any tests that exposed the bug.

We immediately set out to rectify the situation by creating tests that failed as a result of the bug. Once these tests were created, it was a fairly simple process to use those tests as a debug platform to step through the code, find the problem and correct the bug. As is sometimes the case, fixing that bug caused another test to fail, a situation that was easily remedied since we knew about it due to the failing test.

After the code was complete and checked-in for build, the developer I was working with remarked on how he now "got it". He had heard the words before, "…write a test to expose the bug, then fix the bug." but they were empty words until he actually experienced using a test to do the debugging, and then saw existing tests prevent a regression failure in other code due to our bug fix. It is an experience all TDD practitioners have at some point and it is easy to forget that others may not yet have grokked the concepts behind the process.

Coincidentally, that very night, I got a ping from my friend Jeremy Clark (blog, twitter) asking for comments on his latest YouTube video on TDD. After watching it, I really couldn't offer any constructive criticism for him because there was absolutely nothing to criticize. As an introduction to the basics of TDD, I don't think it could have been done any better. If you are just getting started with TDD, or want to get started with TDD, or want a refresher on the basics of TDD, you need to watch this video.

Jeremy has indicated he will be doing more in this series in the future, delving deeper into the topic of TDD. Perhaps he will include an example of fixing a bug in existing code in a future video.

Tags: , , , , , , , , , , , , , | Categories: Development Posted by bsstahl on 7/11/2014 8:53 PM | Comments (0)

I recently started working on a set of open-source projects for Code Camps and other community conferences with my friend Rob Richardson (@rob_rich). In addition to doing some good for the community, I expect these projects, which I will describe in more detail in upcoming posts, to allow me to experiment with several elements of software development that I have been looking forward to trying out. These include:

  • Using Git as a source control repository
  • Using nUnit within Visual Studio as a test runner
  • Solving an optimization problem in C#
  • Getting to work on a shared project with and learning from Rob

As an enterprise developer, I have been using MSTest and Team Foundation Server since they were released. My last experience with nUnit was probably about 10 years ago, and I have never used Git before. My source control experience prior to TFS was in VSS and CVS, and all of that was at least 6 or 7 years ago.

So far, I have to say I'm very pleased with both Git for source control, and nUnit for tests. Honestly, other than for the slight syntactical changes, I really can't tell that I'm using nUnit instead of MSTest. The integration with Visual Studio, once the appropriate extensions are added, is seamless. Using Git is a bit more of a change, but I am really liking the workflow it creates. I have found myself, somewhat automatically, committing my code to the local repository after each step of the Red-Green-Refactor TDD cycle, and then pushing all of those commits to the server after each full completion of that cycle. This is a good, natural workflow that gives the benefits of frequent commits, without breaking the build for other developers on the project. It also has the huge advantage of being basically unchanged in a disconnected environment like an airplane (though those are frequently not disconnected anymore).

The only possible downside I can see so far is the risk presented by the fact that code committed to the local repository, is not yet really safe. Committing code has historically been a way of protecting ourselves from disc crashes or other catastrophes. In this workflow, it is the push to the server, not the act of committing code, that gives us that redundancy protection. As long as we remember that we don't have this redundancy until we push, and make those pushes part of the requirements of our workflow, I think the benefits of frequent local commits greatly outweigh any additional risk.

As to the other two items on my list, I have already learned a lot from both working with Rob and in working toward implementing the optimization solution. Even though we've only been working on this for a few days, and have had only 1 pairing session to this point, I feel quite confident that both the community and I will get great benefit from these projects.

In my next post, I'll discuss what these projects are, and how we plan on implementing them.

Tags: , , , , , , | Categories: Development Posted by bsstahl on 4/4/2014 9:26 PM | Comments (0)

One thing I've noticed during my 30 years in software engineering is that everything old eventually becomes new again.  If you have a particular skill or preferred methodology that seems to have become irrelevant,  just wait a while, it is likely to return in some form or another.  In this case, it seems that recent announcements by Microsoft about how developers will be able to leverage the power of Cortana, are likely to revitalize the need for text processing as an input to the apps we build.

At one time, many years ago, we had two primary methods of letting the computer know what path we wanted to take within an application; we could select a value from a displayed (textual) menu, or, if we were getting fancy, we could provide an input box that the user could type commands into.  This latter technique was often the purview of text-only adventure games and inputs came in the form "move left" and "look east".  While neither of these input methods was particularly exciting or "natural" to use today's parlance, it was only text input that allowed the full flexibility of executing nearly any application action from any location.  Now that Microsoft has announce that developers on Windows Phone, and likely other platforms, will be able to leverage the platform's built-in digital assistant named "Cortana" and receive inputs into their applications as text input translated from the user's speech (or directly as text typed into Cortana's input box) it makes sense for us to start thinking about our application inputs in this way again. That is, we want to consider, for each action a user might take, how the user might trigger that action by voice command.

It should be fairly easy to shift to this mindset if we simply imagine, on our user interfaces, a text box where the user could type a command to the app.  The commands that the user might type into this box are the commands we need to enable using the provided speech input APIs.  If we start thinking about inputs in this way now, it might help to shape our user interfaces in ways that make speech input more natural, and our applications more useful, in the coming years. Of course, this also gives us the added benefit of allowing us to reuse our old text parsing skills from that time when we wrote that adventure game…


Tags: , , , | Categories: Event Posted by bsstahl on 4/6/2011 5:21 PM | Comments (0)
I am very excited to once again be attending the annual Day of ScottGu in Arizona. If you haven't been to this event before, you need to sign up right now (below). Those who have been to previous events are probably already signed-up. For more information, see the text below the signup form or the AZGroups website.

It's here again - Mr. Scott Guthrie is coming back to Arizona. And this year we're bringing special A-LIST guest, Mark Russinovich. Scott is a Vice President at Microsoft in charge of the Web Stack (ASP.net + Silverlight + a bunch of other stuff) Scott has made a special visit to the Arizona.net User Group since 2003 and is committed to the Arizona.net community as long as we can continue to support the event (in attendance).

ScottGu runs a bunch of business product lines inside Microsoft, most revolving around the Web Stack. This included ASP.net Web Forms, MVC, NuGet, Silverlight, and I'm sure a bunch of other things that aren't even public (hint hint).

So What Will ScottGu be demo'ing? Answer: I don't know. Scott says it will be magical like always, but at this moment, I'm not sure what he's going to be talking about.

But maybe that's even a better schedule to have. In years past, I have literally had to rush Mr. Scott Guthrie off the stage, which seems silly. Silly in that we wait all year for him to show up, and then don't give him the time he wants. So this year we're having less sponsored stage time, and more Scott Guthrie Time. (insert hoops and hollars here).

Tags: , | Categories: Development Posted by bsstahl on 4/18/2009 10:05 PM | Comments (0)

Justin James at TechRepublic posts his top-10 list of skills developers will need over the next 5 years.

His list:

  1. One of the “Big Three” (.NET, Java, PHP)
  2. Rich Internet Applications (RIAs)
  3. Web development
  4. Web services
  5. Soft skills
  6. One dynamic and/or functional programming language
  7. Agile methodologies
  8. Domain knowledge
  9. Development “hygiene”
  10. Mobile development


The areas where I have concerns are 5, 6, 9 & 10. What about you?