Blogs

C# does not automatically curry functions, so a function that multiplies two double s together and returns the result must be assigned to a delegate that takes two arguments and returns a result: Func < double , double , double > multiply = (a, b) => a * b; This seems reasonable, but unfortunately it means that if we want to define a partial application of the function where one argument is...

Last time I wrote Shuffle and TakeRandom extension methods for IEnumerable<T> which use the Fisher-Yates algorithm to perform an unbiased shuffle of a sequence and take a random subset from it. In order to optimise the performance of the TakeRandom method I had to reverse the documented implementation of the shuffle so it produced the results at the start of the sequence rather than the end,...

One of the things that web sites tend to do frequently is look up the country a user is from based on their IP address, for example to direct them to the appropriate site for their country or to restrict content that cannot be legally shown to them. There are numerous solutions to perform this mapping such as calling third-party web services or looking up the country from a database, but as it is such...

The article Roots of the REST/SOAP Debate (along with many others like it) claims that SOAP web services have a limitation in that resources they work with are not directly addressable via a URI, but that you have to connect to the SOAP endpoint and then call a method on it. The analogy used is as follows: Let me offer an analogy. Suppose you were living temporarily in a hotel. The hotel might not...

The other week Jeff Atwood posted a blog entry named Coding Without Comments that stated... well I'm actually not sure. It started by making the valid point that comments should indicate why your code works the way it does and shouldn't be needed to explain what it does, but then went entirely off track and ended up pretty much stating that all comments are detrimental to code quality (emphasis...

The normal use for the CASE expression in T-SQL is to perform simple modifications to one of the columns in a SELECT statement; the type of example given in MSDN show it being used to expand state abbreviations such as 'CA' to 'California', or to categorise products into 'Cheap' and 'Expensive' depending on their price. However, the CASE expression is a lot more flexible...

Databases cause two performance problems for applications. Firstly they are difficult to scale out compared to other server roles which means they can easily become the scalability bottleneck, and secondly they are on a remote machine which means that each query made to them involves network latency. To reduce processing overhead and latency, a common approach is to make as few queries as possible...

Some languages such as C# let you treat the System.Decimal type as an integral type most of the time, even having the keyword decimal , and will let you declare constant fields of the type under some circumstances. However, decimal isn't a primitive type in the same way as the other numerics, and is implemented quite differently from them. At CIL level, you can't actually declare a constant...