docs/man/help2txt.py

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"""
Convert --help output of a program into asciidoc text format.
"""
from __future__ import print_function
from __future__ import unicode_literals
from __future__ import division
from __future__ import absolute_import

from subprocess import Popen, PIPE, CalledProcessError

import re, sys

IS_PY2 = sys.version_info[0] == 2
if IS_PY2:
    PY_STRING_TYPE = basestring  # noqa: F821
else:
    PY_STRING_TYPE = str

def check_output(args, stdin=None, stderr=None, shell=False, universal_newlines=False, **kwargs):
    """
    Run command args and return its output as a byte string.
    kwargs are passed through to L{subprocess.Popen}
    @return: stdout of command (mixed with stderr if stderr=STDOUT)
    @raise L{CalledProcessError}: If command returns non-0 exit status.
    """
    if "stdout" in kwargs:
        raise ValueError("Must not specify stdout in check_output")
    p = Popen(args, stdout=PIPE, stdin=stdin, stderr=stderr, shell=shell, universal_newlines=universal_newlines, **kwargs)
    out, err = p.communicate()
    if p.returncode:
        e = CalledProcessError(p.returncode, args)
        e.output = err or out
        raise e
    return out

def help2txt(help_out):
    VALUE = r"(?:[\w-]+|<[^>]+>)"
    DEFAULT = r"(?: +\([^)]+\))?"
    OPTION = r"-[\w-]+(?:[ =]%s)?%s" % (VALUE, DEFAULT) # -opt[(=| )value][(default)]
    OPTIONS = r"%s(?:, *%s)*" % (OPTION, OPTION)        # opt[,opt...]
    HELP = r"(?:[ \t]+\w.*$)|(?:(?:\n[ \t]+[^-\s].*$)+)" # same line or following lines indented.
    OPT_HELP = r"^\s+(%s)(%s)" % (OPTIONS, HELP)
    SUBHEAD = r"^((?: +\w+)*):$"

    # check_output returns binary in py3
    if not isinstance(help_out, PY_STRING_TYPE):
        help_out = help_out.decode()

    options = re.search("^Options:$", help_out, re.IGNORECASE | re.MULTILINE)
    if (options): help_out = help_out[options.end():]
    result = ""

    def heading(text, depth):
        return "%s %s\n\n" % ("="*depth, text)

    for item in re.finditer(r"%s|%s" % (OPT_HELP, SUBHEAD), help_out, re.IGNORECASE | re.MULTILINE):
        if item.group(3):
            result += heading(item.group(3).strip(), 3)
        else:
            result += "%s\n:   %s\n\n" % (item.group(1), re.sub(r"\s+", " ", item.group(2)).strip())
    return result

def main(argv):
    if len(argv) < 2: raise ValueError("Wrong number of arguments\nUsage %s"
                                       " <program> [args,...]" % argv[0])
    program = argv[1:]
    print(help2txt(check_output(program)))

if __name__ == "__main__":
    main(sys.argv)