densecode.py

#!/usr/bin/env python3

'''
Module counts how dense is Python source code in
terms of lexical entities per LoC.
'''

import ast


def traverse(node, line_nos):
    '''
    go through the AST and count lines
    '''
    children = list(ast.iter_child_nodes(node))

    try:
        current_line = node.lineno
    except AttributeError:
        current_line = 0

    count = 1
    line_nos.update([current_line])

    if len(children) == 0:
        return 1

    for child in ast.iter_child_nodes(node):
        count += traverse(child, line_nos)

    return count


def count_code_entities(source):
    '''
    parse the source&count
    '''
    line_nos = set()
    tree = ast.parse(source)
    # -1, to compensate for line 0 which serves as default
    # for lexical entities not having lineno property
    return traverse(tree, line_nos), len(line_nos) - 1


def main():
    '''
    parsin&stuff
    '''
    from argparse import ArgumentParser, FileType
    parser = ArgumentParser()
    parser.add_argument('infile',
                        help='source file to analyze',
                        type=FileType(),
                        default='-',
                        nargs='?',)

    args = parser.parse_args()

    with args.infile as file:
        source = file.read()
        name = file.name

    count, number = count_code_entities(source)
    print(name, ': ', round(count/number, 4), 'entities/line of code')


if __name__ == '__main__':
    main()