NePA TesT: Community Network Emulator

def splitArgs( argstr ):

    """Split argument string into usable python arguments

       argstr: argument string with format fn,arg2,kw1=arg3...

       returns: fn, args, kwargs"""

    split = argstr.split( ',' )

    fn = split[ 0 ]

    params = split[ 1: ]

    # Convert int and float args; removes the need for function

    # to be flexible with input arg formats.

    args = [ makeNumeric( s ) for s in params if '=' not in s ]

    kwargs = {}

    for s in [ p for p in params if '=' in p ]:

        key, val = s.split( '=' )

        kwargs[ key ] = makeNumeric( val )

    return fn, args, kwargs

def customConstructor( constructors, argStr ):

    """Return custom constructor based on argStr

    The args and key/val pairs in argsStr will be automatically applied

    when the generated constructor is later used.

    """

    cname, newargs, kwargs = splitArgs( argStr )

    constructor = constructors.get( cname, None )

    if not constructor:

        raise Exception( "error: %s is unknown - please specify one of %s" %

               ( cname, constructors.keys() ) )

    def customized( name, *args, **params ):

        "Customized constructor, useful for Node, Link, and other classes"

        params.update( kwargs )

        if not newargs:

            return constructor( name, *args, **params )

        if args:

            warn( 'warning: %s replacing %s with %s\n' % (

                  constructor, args, newargs ) )

        return constructor( name, *newargs, **params )

    return customized

def buildTopo( topos, topoStr ):

    """Create topology from string with format (object, arg1, arg2,...).

    input topos is a dict of topo names to constructors, possibly w/args.

    """

    topo, args, kwargs = splitArgs( topoStr )

    if topo not in topos:

        raise Exception( 'Invalid topo name %s' % topo )

    return topos[ topo ]( *args, **kwargs )