pyone: python one liner

pyone

#!/usr/bin/env python
help = '''
python one liner

Usage: pyone [OPTIONS] code [OPTIONS] [--] [file1, file2, ...]
    -e code
    -E code
    -l
    -Mmodule[,module,...]
    -n
    -p
    --pre=code
    --post=code
    --ic=encoding
    --oc=encoding
    --eerror=strict, ignore, or replace, ...

e.g.
$ pyone "print(sys.platform)"
$ pyone "0 and print('a')"
$ pyone "1 and print('a')"
$ pyone "0 or print('a')"
$ pyone "1 or print('a')"
$ pyone -nle "print(_ * 2)" < hoge.txt
$ pyone -ple "_ = _ * 2" < hoge.txt
$ pyone -ple "_ = _ * 2" *.txt
$ pyone -Mimp -e "print(imp.__name__)"
$ pyone --pre="print(0)" --post="print(2)" "print(1)"
$ pyone --ic=euc-jp --oc=utf-8 --error=replace -ple 0 hoge.txt
$ pyone -ple "_ = _ if int(_) % 2 == 0 else _noprint"

If -n or -p option is specified, code is executed for each line, and variable _ refers each line.
If -p option is specified, _ is printed after execution.

_argv variable has arguments.
$ pyone -e "print(_argv)" a b
['a', 'b']
'''


import sys
import codecs
from collections import defaultdict


def readArgv():
    options = defaultdict(lambda: None)
    options['M'] = set()
    options['eerror'] = 'strict'

    isProgram = False
    isFile = False
    _argv = []
    for item in sys.argv[1:]:
        if isProgram:
            options['e'] = item
            isProgram = False
            continue
        if isFile:
            _argv.append(item)
        elif item == '--':
            isFile = True
            continue
        elif item.startswith('--pre='):
            options['pre'] = item[6:]
        elif item.startswith('--post='):
            options['post'] = item[7:]
        elif item.startswith('--ic='):
            options['ic'] = item[5:]
        elif item.startswith('--oc='):
            options['oc'] = item[5:]
        elif item.startswith('--eerror='):
            options['eerror'] = item[9:]
        elif item[0] == '-':
            if 'M' == item[1]:
                options['M'] |= set(item[2:].split(','))
                continue
            if 'p' in item[1:]:
                options['p'] = True
            if 'n' in item[1:]:
                options['n'] = True
            if 'l' in item[1:]:
                options['l'] = True
            if item[-1] in ('e', 'E'):
                isProgram = True
        elif not options['e']:
            options['e'] = item
        else:
            isFile =True
            _argv.append(item)

    return options, _argv

class NoPrint: pass

if __name__ == '__main__':
    options, argv = readArgv()
    for module in options['M']:
        exec('import ' + module, globals())
    _noprint = NoPrint()

    context = globals().copy()

    if not options['e']:
        print(help)
        exit()
    if options['oc']:
        if sys.version_info[0] >= 3:
            sys.stdout = codecs.getwriter(options['oc'])(sys.stdout.detach())
        else:
            sys.stdout = codecs.getwriter(options['oc'])(sys.stdout)
    if options['pre']:
        exec(options['pre'], context)
    if options['p'] or options['n']:
        if len(argv) > 0:
            for filename in argv:
                try:
                    file = codecs.open(filename, 'r', encoding=options['ic'], errors=options['eerror'])
                    for _ in file:
                        if options['l']:
                            _ = _.rstrip('\r\n')
                        context['_'] =  _
                        exec(options['e'], context)
                        if options['p'] and context['_'] is not _noprint:
                            print(context['_'])
                finally:
                    file.close
        else:
            if options['ic']:
                if sys.version_info[0] >= 3:
                    sys.stdin = codecs.getreader(options['ic'])(sys.stdin.detach())
                else:
                    sys.stdin = codecs.getreader(options['ic'])(sys.stdin)
            for _ in sys.stdin:
                if options['l']:
                    _ = _.rstrip('\r\n')
                context['_'] =  _
                exec(options['e'], context)
                if options['p'] and context['_'] is not _noprint:
                    print(context['_'])
    else:
        context['_argv'] =  argv
        exec(options['e'], context)
    if options['post']:
        exec(options['post'], context)