Pycom: A Python Compiler

Usage

./pycom.py (flags) [source file]

Flags

• -i (bool):
  Print additional information about compilation (such as time taken). Defaults to off.

• -r (bool):
  Run the generated executable automatically after compilation. Defaults to off.

• -rd (bool):
  Run the generated executable automatically after compilation, and then delete it. Defaults to off.

• -o [output] (string):
  The string specified after the flag will be the name of the generated executable. Defaults to the name of the Python file that was passed in.

• -fm | --fastmath (bool):
  Perform aggressive optimisations speed on calculations at the cost of some precision. Defaults to off.

What is Pycom?

Pycom is effectively a compiler for Python code, bringing it down to a native executable with C++ as 'intermediate representation'. It supports all of the BASIC-like syntax of Python along with a lot of the standard library and inbuilt functions. To see what is currently supported and not supported, check the 'Examples' section below.

Why and when use Pycom?

Python is slow. While many optimisations and new implementations of it have vastly improved its speed, generating native code that can run as a standalone executable from Python code has never really been done. As a result, no matter what, Python code has never hit levels of speed and portability that C/C++. Pycom aims to tackle this.

Due to Pycom (currenly) not supporting all Python features from all versions, you should only really use it if you want to run simple applications that require high speed (again, check 'Examples')

Examples

What Pycom supports and is good at:

High iteration loops:

for i in range(1, 1000001):
    if i % 3 == 0:
        print(i)

Speed benchmarks and comparisons

Benchmark	CPython	Pycom	Pycom with --fastmath	pypy
Multiples of 3 and 5	9.383s	0.133s	0.106s	0.495s
Primes	17.127s	4.441s	3.994s	4.577s
Stack Operations	8.857s	2.132s	1.992s	3.113s

(All of these can be found under ./benchmarks/)

Supported Features

• All 'turing complete' features of Python: if, else, for, while, etc.
• f'' strings
• Some in built functions
• Some math library functions
• List comprehensions

Not supported yet

• Pythonic ways of writing certain blocks (one line if...else, etc.)
• A lot of libraries included in stdlib