Polyglotting

Rails Notes

I'm reading through Agile Web Development With Rails tonight and have come across a couple of interesting tidbits that may be good to know later.

When writing code in .rhtml files

<% 3.times do %>
  Test<br />
<% end %>

will result in the following html

Test<br />

Test<br />

Test<br />

to prevent this add a minus (-) before the close of the code sections to indicate that the last line break should be ignored.

<% 3.times do -%>
  Test<br />
<% end -%>

Also there is a helper method "h" that is really nice. It will parse any string into the markup required to cause the string to be rendered as it should. This eases site design and helps to protect from some hacks. So

<% h("3 < 4") %>

is translated to

3 &lt; 3

as desired.

Also something that is worth noting is that the views have access to all instance variables in the controller that calls them, even private variables.

String to number conversion in Ruby

When converting a string in Ruby to and in using the value's to_i method it will do some interesting conversion.

Examples:

• '5' becomes 5 -- Cool
• 'I have 5' becomes 0 -- kind of a weird failure, 0 could be a perfectly fine conversion
• '5 is five' becomes 5 -- Really odd behavior, but the conversion is done until an incorrect character is encountered.  After this the rest of the string is ignored.  So
• '5 is 5' becomes 5
• '5,000' becomes 5

Where this is helpful so far is when someone is entering text through the command prompt.  When a person enters text prompted from gets the new line added from the user pressing enter is included.  So if a user enters 5, then the gets string contains '5\n'.  In most languages this would cause and issue, but with how ruby does it's conversion of '5\n' becomes 5.

String Multiplication in Ruby

This is pretty interesting. In ruby you can multiply a string. So if you wanted you could write

puts 'Repeat ' * 3

Which outputs:

Repeat Repeat Repeat

I like this and I do think it makes sense.  It does not work if you write

puts 3 * 'Repeat '

Which I think is wrong because multiplication should be commutative.

 

Now doing this has somewhat caused a problem for concatenation though.  By multiplying string it is not clear what should happen when you do this.

puts 'Repeat ' + 3

So ruby outputs an error, something that I've enjoyed recently in .NET has been that if you add or concatenate a string with another object the other object is automatically changed to a string, using the ToString method I believe. 

I would think that this is a much more common scenario than multiplying strings and therefore a bigger loss to productivity and readability of code.

First Ruby WTF

Well I was reading through Chris Pine's Learn to Program and he made a curious statement about how money is handled when programming.

In practice, most programs don't use floats; only integers. (After all, no one wants to look at 7.4 emails, or browse 1.8 web pages, or listen to 5.24 of their favorite songs...) Floats are used more for academic purposes (physics experiments and such) and for 3D graphics. Even most money programs use integers; they just keep track of the number of pennies!

Now does anyone actually do this in the outside of the Ruby world?  When I use .NET I use an ORM and I map to the SQL money column type to a decimal.  I'm somewhat interested to see what ruby does in this situation.

LLBLGen Upgrade from 1.x to 2.x

I have found this search to be pretty helpful with my upgrade from LLBLGen 1 to 2. 

1. To use it start a find and replace and enable regular expressions. 
2. Then in the Find What box enter PredicateFactory.CompareValue\({:w}FieldIndex.{:w}, ComparisonOperator.Equal,
3. now in the Replace with box enter \1Fields.\2 ==

This will then replace the string with the correct syntax for the new query language that uses operator overloads.  These can be modified to capture most of the query types used in LLBLGen.  You will have to go back in however and remove an extra closing parenthesis.

LLBLGen Presentation

The presentations went well.  I think they are definitely something that you have to do to get better.  So now I need to find ways to do more talks.  I enjoyed the chance to get to meet people and discuss technology with people I normally wouldn't. 

The audience for the two presentations I gave were very different.  For the lunch crowd a simple direction was best.  The time was much more crunched and the environment lent itself to more distraction and less interaction.  For the evening you only have 10 people and more time.  So a more in depth presentation would most likely be beneficial for them. 

Other than that I thought that the presentation went well.  It's a large subject that I will get better at presenting when I show to other developers at MTM and present other topics.  I also won something for the first time ever, a book that started out with this quote.

... the highest simplicity of structure is produced, not by a few elements, but by the highest complexity.

- Ralph Waldo Emerson, "Goethe; or, the Writer"

That's a good quote, but I think that the development circle I'm following more and more lately tries to do these Simple Complex things as simply as possible.  I know a lot of developers still like their complexity, hopefully every day I'm less and less like that.

P.S. The presentation material will be posted here very soon.

Mix 07 News

Interesting News from Mix 07.  There has been a lot of attention today to many of Microsoft's announcements about upcoming development projects.  Most notable have been Silverlight 1.1 with built in Cross Platform CLR and Jasper.  But two other interesting bits of technology are ASP.NET Application Services and Dynamic Data Controls.

Dynamic Data Controls for ASP.NET

Dynamic data controls are a set of ASP.NET server controls that obtain database schema information at run time, provide default display formats according to common user expectations, and enable you to easily customize those formats. Watch a video showing how to build a task list application using the Dynamic Data Controls from the ASP.NET Futures Release.

ASP.NET Application Services

New services for ASP.NET enable you to add search to your ASP.NET Web applications, using a commercial search engine’s API (such as Windows Live Search) and custom search providers. You can also publish custom and dynamic sitemaps that are configured to assist search engine crawlers. A new service lets you capture JavaScript errors and report them to server-based ASP.NET code.

Source: ASP.NET Futures: ASP.NET Web: The Official Microsoft ASP.NET 2.0 Site

SPACE.com -- Major Discovery: New Planet Could Harbor Water and Life

How exciting is this news. Scientist's have found a planet that could have liquid water.  I'm not sure what kind of affect being the planet of a red dwarf would have on the biology that would take place, but hopefully some space based telescopes will have a high enough resolution to directly observe the planet soon.

If we can get a clear night this weekend I will try to view Gliese 581 and post the picture.  It won't be too amazing, but the idea that it may have life is.

Link to SPACE.com -- Major Discovery: New Planet Could Harbor Water and Life

Storm Chasing?

We set out today at 2:30 to get in position to start our chase.  The "1st" line had just passed over and everyone was talking about the ominous second round that was soon to be firing.  We had circled this day Sunday since the Storm Prediction Center had marked it as high risk in most of Oklahoma. 

This was going to be an exciting day.  I hadn't chased in nearly two years, but it seemed like today was finally going to be a can't miss type of day.  Well we just finished a beautiful scenic drive of SW Oklahoma.  We didn't see any storms. In fact this is what most of the day looked like.

After about 3 hours of waiting for this beautiful day to turn into the apocalyptic storm factory we decided to head back home and wait til the next time.

Ben Hall's Blog: MbUnit RowTest

Ben has a post about a pretty handy feature available in MBUnit.  You can create a test that accepts parameters and then user RowTest to define different parameters for the tests.  You can even specify what exception any particular parameter list is supposed to generate.

Link to Ben Hall's Blog: MbUnit RowTest