Generics or Metaprogramming? Declarative macros with Rust

Smartly read inputs from standard input

Reading inputs from command line is probably the first task competitive coders do as they start to solve complex problems. While numerous languages are used by thousands of coders everyday, some emerge out as the popular ones; hello C++! One of the most powerful tools to write high performance programs. But… with great power, comes responsibility of managing memory *manually (Let’s not get into modern C++). While competitive coders do not care about (much) about de-allocating memory on an online judge, it is a pretty critical task for production systems to clean up and reclaim memory. Let’s bring our language into picture now; a language that offers several high level APIs, while being close to metal. Welcome to Rust!

Eh.. why mention C++ then?

This post will take 3 approaches to read input from standard input and will try to parse to required data type. For the sake of simplicity, let’s assume we wish to read a 32bit integer and a 32bit floating point number.

The concrete:

Can we not have 2 concrete implementations?
We sure can! Let’s quickly look at it:

While this gets the job done, but what if we want to extend our reader to other types? This approach will require rewriting another function altogether.

How about generics?

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