Source code for pyutil.ptags

#!/usr/bin/python3
"""Create a tags file for Python programs, usable with vi.

Currently uses a regex to create a tags file.

Files to tag
------------
- functions (even inside other defs or classes)
- classes
- filenames

Warns about files it cannot open.

No warnings about duplicate tags.

Snagged from the scripts dir in python3.6-examples.

.. todo:: Use ipdb and step through while watching the tags var.


Otherwise add in `PEP 257`_ compliant params.
Try different styles and see what you like.


.. _PEP 257:
    https://www.python.org/dev/peps/pep-0257

"""
import os
import re
import sys


def main():
    """Handle CLAs and work with writing the tags file."""
    args = sys.argv[1:]
    for filename in args:
        treat_file(filename)
    if tags:
        fp = open('tags', 'w')
        tags.sort()
        for s in tags:
            fp.write(s)


def treat_file(filename):
    """Find usable matches for tags file.

    Parameters
    ----------
    filename : path-like object
        File to generate tags from.

    Returns
    -------
    None : None

    """
    try:
        fp = open(filename, 'r')
    except Exception:
        sys.stderr.write('Cannot open %s\n' % filename)
        return
    base = os.path.basename(filename)
    if base[-3:] == '.py':
        base = base[:-3]
    s = base + '\t' + filename + '\t' + '1\n'
    tags.append(s)
    while 1:
        line = fp.readline()
        if not line:
            break
        m = matcher.match(line)
        if m:
            content = m.group(0)
            name = m.group(2)
            s = name + '\t' + filename + '\t/^' + content + '/\n'
            tags.append(s)


if __name__ == '__main__':
    tags = []
    expr = r'^[ \t]*(def|class)[ \t]+([a-zA-Z0-9_]+)[ \t]*[:\(]'
    matcher = re.compile(expr)
    main()