# -*- encoding: utf-8 -*-
#
# Copyright P. Christeas <p_christ@hol.gr> 2008,2009
#
#
# WARNING: This program as such is intended to be used by professional
# programmers who take the whole responsability of assessing all potential
# consequences resulting from its eventual inadequacies and bugs
# End users who are looking for a ready-to-use solution with commercial
# garantees and support are strongly adviced to contract a Free Software
# Service Company
#
# 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 2
# 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, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
###############################################################################

__export_bis = {}

def __init_ebis():
	global __export_bis
	
	_evars = [ 'abs', 'all', 'any', 'basestring' , 'bin', 'bool', 
		'chr', 'cmp','complex', 'dict', 'divmod', 'enumerate',
		'float','format', 'frozenset', 'getattr', 'hasattr', 'hash',
		'hex', 'id','int', 'iter', 'len', 'list', 'long', 'map', 'max',
		'min','next', 'oct', 'ord','pow', 'range', 'reduce', 'repr',
		'reversed', 'round', 'set', 'setattr', 'slice','sorted', 'str',
		'sum', 'tuple','type', 'unichr','unicode', 'xrange',
		'True','False', 'None', 'NotImplemented', 'Ellipsis', ]
		
	for v in _evars:
		__export_bis[v] = __builtins__[v]
	

__init_ebis()


def safe_eval(expr,sglobals,slocals = None):
	""" A little safer version of eval().
	    This one, will use fewer builtin functions, so that only
	    arithmetic and logic expressions can really work """
	
	global __export_bis

	if not sglobals.has_key('__builtins__'):
		# we copy, because we wouldn't want successive calls to safe_eval
		# to be able to alter the builtins.
		sglobals['__builtins__'] = __export_bis.copy()
		
	return eval(expr,sglobals,slocals)
	
#eof
Implement safe_eval() in order to armour eval()