# -*- coding: iso-8859-1 -*-
"""
Handling of arguments: options, arguments, file(s) content iterator
For small scripts that:
- read some command line options
- read some command line positional arguments
- iterate over all lines of some files given on the command line, or stdin if none given
- give usage message if positional arguments are missing
- give usage message if input files are missing and stdin is not redirected
"""
__author__ = 'Peter Kleiweg'
__version__ = '0.2'
__date__ = '2004/08/28'
import os, sys, getopt
class Args:
"""
Perform common tasks on command line arguments
Instance data:
progname (string) -- name of program
opt (dictionary) -- options with values
infile (string) -- name of current file being processed
lineno (int) -- line number of last line read in current file
linesum (int) -- total of lines read
"""
def __init__(self, usage='Usage: %(progname)s [opt...] [file...]'):
"init, usage string: embed program name as %(progname)s"
self.progname = os.path.basename(sys.argv[0])
self.opt = {}
self.infile = None
self.lineno = 0
self.linesum = 0
self._argv = sys.argv[1:]
self._usage = usage
def __iter__(self):
"iterator: set-up"
if self._argv:
self.infile = self._argv.pop(0)
self._in = open(self.infile, 'r')
self._stdin = False
else:
if sys.stdin.isatty():
self.usage() # Doesn't return
self.infile = '<stdin>'
self._in = sys.stdin
self._stdin = True
return self
def next(self):
"iterator: get next line, possibly from next file"
while True:
line = self._in.readline()
if line:
self.lineno += 1
self.linesum += 1
return line
if self._stdin:
break
self._in.close()
try:
self.infile = self._argv.pop(0)
except IndexError:
break
self.lineno = 0
self._in = open(self.infile, 'r')
self.lineno = -1
self.infile = None
raise StopIteration
def getopt(self, shortopts, longopts=[]):
"get options and merge into dict 'opt'"
try:
options, self._argv = getopt.getopt(self._argv, shortopts, longopts)
except getopt.GetoptError:
self.usage()
self.opt.update(dict(options))
def shift(self):
"pop first of remaining arguments (shift)"
try:
return self._argv.pop(0)
except IndexError:
self.usage()
def pop(self):
"pop last of remaining arguments"
try:
return self._argv.pop()
except IndexError:
self.usage()
def warning(self, text):
"print warning message to stderr, possibly with filename and lineno"
if self.lineno > 0:
print >> sys.stderr, '%s:%i: warning: %s' % (self.infile, self.lineno, text)
else:
print >> sys.stderr, '\nWarning %s: %s\n' % (self.progname, text)
def error(self, text):
"print error message to stderr, possibly with filename and lineno, and exit"
if self.lineno > 0:
print >> sys.stderr, '%s:%i: %s' % (self.infile, self.lineno, text)
else:
print >> sys.stderr, '\nError %s: %s\n' % (self.progname, text)
sys.exit(1)
def usage(self):
"print usage message, and exit"
print >> sys.stderr
print >> sys.stderr, self._usage % {'progname': self.progname}
print >> sys.stderr
sys.exit(1)
if __name__ == '__main__':
a = Args('Usage: %(progname)s [-a value] [-b value] [-c] word [file...]')
a.opt['-a'] = 'option a' # set some default option values
a.opt['-b'] = 'option b' #
a.getopt('a:b:c') # get user supplied option values
word = a.shift() # get the first of the remaining arguments
# use a.pop() to get the last instead
for line in a: # iterate over the contents of all remaining arguments (file names)
if a.lineno == 1:
print 'starting new file:', a.infile
a.warning(line.rstrip())
print 'Options:', a.opt
print 'Word:', word
print 'Total number of lines:', a.linesum
print 'Command line:', sys.argv # unchanged
a.warning('warn 1') # print a warning
a.error('error') # print an error message and exit
a.warning('warn 2') # this won't show
