Source code for pipelet.directive

## Copyright (C) 2008, 2009, 2010 APC LPNHE CNRS Universite Paris Diderot <lejeune@apc.univ-paris7.fr>  <betoule@apc.univ-paris7.fr>
## 
## 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/gpl.html

import shlex

class Directive:
    """ Parse the segment code to get directives (multiplex, depend,
    ...)
    """
    def parse(self, code):
        """ Parse the code to initialiaze directive names and values.
        
        Directive names and value are class attributs. 

        """
        try:
            l = shlex.split(code)
        except ValueError:
            raise StopIteration()
        it = iter(l)
        if it.next() != self._name:
            raise StopIteration()
        for e in it:
            if self.__dict__.has_key(e):
                try:
                    setattr(self, e, it.next())
                except StopIteration:
                    raise ValueError("The string is not a valid directive\n"+self._usage)
            else:
                try:
                    getattr(self,self._args).append(e)
                except AttributeError:
                    setattr(self, self._args, e)
                    
class Multiplex(Directive):
    """ Multiplex directives are used to control the pipeline
    parallelisation scheme.
    """
    _name  = "#multiplex"
    _usage = "#multiplex method where 'condition' group_by 'value'"
    _args  = "method"

    def __init__(self):
        """ Init the multiplex directive. 
        """

        ## string, multiplex method
        self.method   = "cross_prod"

        ## string, mutliplex condition
        self.where    = ""

        ## string, gathering condition
        self.group_by = ""

class Depend(Directive):
    """ Depend directive are used to include external code to the
    hashkey computation.
    """
    _name  = "#depend"
    _usage = "#depend file1 file2 ..."
    _args  = "deps"
    def __init__(self):
        """ Init the depend directive
        """
        ## list of external code files
        self.deps=[]