What is PyPy?

PyPy is an alternative implementation of Python. While normal Python is built using the C language (hence the alternative term: CPython), PyPy is built on the RPython (Restricted Python) language . RPython constrains the Python language; these constraints mean that PyPy can look at the RPython code, translate it into C code, and then compile it to machine code.

The main aspects of PyPy is the just-in-time (JIT) compiler. Specifically, it uses a tracing JIT, which monitors frequently executed loops and compiles them into native machine code. Since programs frequently spend much of their time in loops, compiling those loops to native code maximizes the speed at which they process data.

Using RPython, the JIT compiler receives known code, that is, the compiler doesn't have to spend time parsing the metadata of the code to determine what type an object is, how much memory space is taken up, and so on. Thus, it is able to effectively convert the CPython code into C code and then to...