How to implement First and FirstOrDefault for boolinq?

Question

I there boolinq - grate opensource LINQ C++ implementation compatable with vs2010. I like its syntax - it looks as close to C# as it gets (from a short look at all other VS2010 LINQ C++ implementations). Yet it really has some base LINQ functions missing. I wonder how can be implemented .First(lambda expression) or .FirstOrDefault(lambda expression) support into it?

Answer 1

Since the c++ vectors have the front() and the empty() method, you just have to do the following:

• for the .First(lambda), you just need to check .Where(lambda).ToVector().empty(). If it is true throw an exception, otherwise return .Where(lambda).ToVector().front()

• for the .FirstOrDefault(lambda), you just need to check .Where(lambda).ToVector().empty(). If it is true return the default value, otherwise return .Where(lambda).ToVector().front()