#!/usr/local/bin/pythonw
# coding: iso-8859-1
# Copyright © 2009 by Amos Newcombe
# 
# This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
# 
# This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
# 
# You should have received a copy of the GNU General Public License along with this program.  If not, see <http://www.gnu.org/licenses/>.

'''a generic command-line program to be used as a framework
'''

import sys
from optparse import OptionParser

class commander:
	'a base class to interpret a command line'
	
	# ¤ Metadata
	
	sUsage = None
	sVersion = '%prog 2008.06.22.0'
	
	# ¤ Creation
	
	def __init__(self, lsLine):
		'Initialize self.'
# 		print '%s(%s)' % (self.__class__.__name__, ', '.join(lsLine))
		self.lsLine = lsLine
		self.optParser = OptionParser(usage=self.sUsage, version=self.sVersion)
		self.options()
		self.opt, self.lsArgs = self.optParser.parse_args()
# 		print '%s(%s)' % (self.__class__.__name__, ', '.join(self.lsArgs))
		self.ResolveOptions()
	
	def options(self):
		'Populate the option parser with available options.'
		pass # STUB
	
	def ResolveOptions(self):
		'Interpret the command line options.'
		pass # STUB
	
	# ¤ Description
	
	def __str__(self, sName=None):
		'Reproduce the command line (bug: some args need quotes).'
		return ' '.join(self.lsLine) # BUG: args with spaces are not quoted
	
	def __repr__(self):
		'Reproduce the Python instantiation call.'
		return '%s(%s)' % (self.__class__.__name__, repr(self.lsLine))
	
	# ¤ Operation
	
	def main(self):
		'Pass each command line argument to self.main1().'
# 		print '%s.main()' % self.__class__.__name__
		for sArg in self.lsArgs: self.main1(sArg)
	
	def main1(self, sArg):
		'Echo a command line argument on its own line.'
		print 'arg: %s' % `sArg` # STUB: echo command line arguments

class evaluator(commander):
	'abstract base class for a commander that applies a function to arguments from the command line and optionally standard input'
	
	# ¤ Creation
	
	def options(self):
		'Populate the option parser with available options.'
		commander.options(self)
		self.optParser.add_option('-i', '--stdin',
			action='store_true', dest='useStdin', default=False,
			help='get additional arguments from stdin'
		)
	
	# ¤ Operation
	
	def main(self):
		'Process the command line and optionally standard input.'
		if self.lsArgs:
			for sArg in self.lsArgs: print self.main1(sArg),
			print
		if self.opt.useStdin:
			for sLine in sys.stdin:
				for sArg in sLine.strip().split(): print self.main1(sArg),
				print
	
	def main1(self, sArg):
		'Apply self.function() to the argument.'
		try                     : return self.function(sArg)
		except StandardError, ex: return 'ERROR: ' + repr(ex)
	
	def function(self, sArg):
		'Define this to be the function you want to apply to the arguments.'
		raise NotImplementedError, '%s.function()' % self.__class__.__name__

if __name__ == '__main__':
	
	import sys
	commander(sys.argv).main()