Show HN: One flew over the variadic template arguments

1 point

5 years ago

Python is a dynamically -- run-time -- typed language. That creates big advantages and big disadvantages. The advantage: it makes it very versatile and heterogeneously functional. For example, you could easily have heterogeneous containers. You could easily loop through them and your loop variable is dynamically evaluated. Also, you could have heterogeneous interfaces, … The disadvantage: it is very inefficient. For example, in the above loop, the loop variable type must be determined at each iteration. That’s extremely inefficient -- although there are ways under certain circumstances to avoid that.

C++, on the other hand, is statically and moderately-strongly typed language. So, you cannot – without using pointers which is inefficient – have heterogeneous containers because you must know all types at compile time. Also, you cannot have heterogeneous interfaces, … Enter the _ variadic template arguments_. This modern C++ feature makes it possible to have some aspects of heterogeneity without the disadvantage of inefficiency. Variadic template arguments help in designing interfaces for heterogeneous containers. As an example, please look at [DataFrame](https://github.com/hosseinmoein/DataFrame) which implements a C++ heterogeneous container. Look at member methods load_data()(https://htmlpreview.github.io/?https://github.com/hosseinmoein/DataFrame/blob/master/docs/HTML/load_data.html), groupby()(https://htmlpreview.github.io/?https://github.com/hosseinmoein/DataFrame/blob/master/docs/HTML/groupby.html), bucketize()(https://htmlpreview.github.io/?https://github.com/hosseinmoein/DataFrame/blob/master/docs/HTML/bucketize.html). I look forward to hearing what you think