parseargs.py

来自「这是一个嵌入式linux系统下的命令工具包」· Python 代码 · 共 138 行

# Written by Bill Bumgarner and Bram Cohen
# see LICENSE.txt for license information

from types import *
from cStringIO import StringIO


def splitLine(line, COLS=80, indent=10):
    indent = " " * indent
    width = COLS - (len(indent) + 1)
    if indent and width < 15:
        width = COLS - 2
        indent = " "
    s = StringIO()
    i = 0
    for word in line.split():
        if i == 0:
            s.write(indent+word)
            i = len(word)
            continue
        if i + len(word) >= width:
            s.write('\n'+indent+word)
            i = len(word)
            continue
        s.write(' '+word)
        i += len(word) + 1
    return s.getvalue()

def formatDefinitions(options, COLS, presets = {}):
    s = StringIO()
    for (longname, default, doc) in options:
        s.write('--' + longname + ' <arg>\n')
        default = presets.get(longname, default)
        if type(default) in (IntType, LongType):
            try:
                default = int(default)
            except:
                pass
        if default is not None:
            doc += ' (defaults to ' + repr(default) + ')'
        s.write(splitLine(doc,COLS,10))
        s.write('\n\n')
    return s.getvalue()


def usage(str):
    raise ValueError(str)


def defaultargs(options):
    l = {}
    for (longname, default, doc) in options:
        if default is not None:
            l[longname] = default
    return l
        

def parseargs(argv, options, minargs = None, maxargs = None, presets = {}):
    config = {}
    longkeyed = {}
    for option in options:
        longname, default, doc = option
        longkeyed[longname] = option
        config[longname] = default
    for longname in presets.keys():        # presets after defaults but before arguments
        config[longname] = presets[longname]
    options = []
    args = []
    pos = 0
    while pos < len(argv):
        if argv[pos][:2] != '--':
            args.append(argv[pos])
            pos += 1
        else:
            if pos == len(argv) - 1:
                usage('parameter passed in at end with no value')
            key, value = argv[pos][2:], argv[pos+1]
            pos += 2
            if not longkeyed.has_key(key):
                usage('unknown key --' + key)
            longname, default, doc = longkeyed[key]
            try:
                t = type(config[longname])
                if t is NoneType or t is StringType:
                    config[longname] = value
                elif t in (IntType, LongType):
                    config[longname] = long(value)
                elif t is FloatType:
                    config[longname] = float(value)
                else:
                    assert 0
            except ValueError, e:
                usage('wrong format of --%s - %s' % (key, str(e)))
    for key, value in config.items():
        if value is None:
            usage("Option --%s is required." % key)
    if minargs is not None and len(args) < minargs:
        usage("Must supply at least %d args." % minargs)
    if maxargs is not None and len(args) > maxargs:
        usage("Too many args - %d max." % maxargs)
    return (config, args)

def test_parseargs():
    assert parseargs(('d', '--a', 'pq', 'e', '--b', '3', '--c', '4.5', 'f'), (('a', 'x', ''), ('b', 1, ''), ('c', 2.3, ''))) == ({'a': 'pq', 'b': 3, 'c': 4.5}, ['d', 'e', 'f'])
    assert parseargs([], [('a', 'x', '')]) == ({'a': 'x'}, [])
    assert parseargs(['--a', 'x', '--a', 'y'], [('a', '', '')]) == ({'a': 'y'}, [])
    try:
        parseargs([], [('a', 'x', '')])
    except ValueError:
        pass
    try:
        parseargs(['--a', 'x'], [])
    except ValueError:
        pass
    try:
        parseargs(['--a'], [('a', 'x', '')])
    except ValueError:
        pass
    try:
        parseargs([], [], 1, 2)
    except ValueError:
        pass
    assert parseargs(['x'], [], 1, 2) == ({}, ['x'])
    assert parseargs(['x', 'y'], [], 1, 2) == ({}, ['x', 'y'])
    try:
        parseargs(['x', 'y', 'z'], [], 1, 2)
    except ValueError:
        pass
    try:
        parseargs(['--a', '2.0'], [('a', 3, '')])
    except ValueError:
        pass
    try:
        parseargs(['--a', 'z'], [('a', 2.1, '')])
    except ValueError:
        pass