def init_subclass_by_name(baseclass, short_name, params):
    """
    Find the subclass, `kls` of baseclass with class attribute `short_name`
    that matches the supplied `short_name`, and then instantiate and return
    that class with:

        return kls(**params)

    This function also tries its best to catch any possible TypeErrors due
    to binding of the arguments, and rethrows them as nicely formatted
    RuntimeErrors that are suitable for showing to users.
    """
    sc = baseclass.__subclasses__()
    for kls in sc:
        if kls.short_name == short_name or \
           (_is_collection(kls.short_name) and short_name in kls.short_name):
            try:
                return kls(**params)
            except TypeError as e:
                spec = inspect.getargspec(kls.__init__)

                # try to give nice errors to the user if the params failed
                # to bind
                if 'unexpected' in str(e):
                    avail = join_quoted(spec.args[1:])
                    raise RuntimeError(
                        "%s's %s. Available params for this subclass are: %s."
                        % (short_name, str(e), avail))
                elif 'takes exactly' in str(e):
                    required = join_quoted(spec.args[1:-len(spec.defaults)])
                    raise RuntimeError(
                        "%s's %s. Required params for this subclass are %s."
                        % (short_name, str(e), required))
                elif 'takes at least' in str(e):
                    required = join_quoted(spec.args[1:-len(spec.defaults)])
                    optional = join_quoted(spec.args[-len(spec.defaults):])
                    raise RuntimeError(
                        "%s's %s. Required params for this subclass are: %s. "
                        "Optional params are: %s" % (
                            short_name, str(e), required, optional))
                # :(
                raise

    chain = itertools.chain.from_iterable(
        e.short_name if _is_collection(e.short_name) else [e.short_name]
        for e in sc)
    avail_names = ', '.join(str(n) for n in chain)
    raise ValueError('"%s" is not a recognized subclass. available names '
                     'are: %s' % (short_name, avail_names))
def init_subclass_by_name(baseclass, short_name, params):
    """
    Find the subclass, `kls` of baseclass with class attribute `short_name`
    that matches the supplied `short_name`, and then instantiate and return
    that class with:

        return kls(**params)

    This function also tries its best to catch any possible TypeErrors due
    to binding of the arguments, and rethrows them as nicely formatted
    RuntimeErrors that are suitable for showing to users.
    """
    sc = baseclass.__subclasses__()
    for kls in sc:
        if kls.short_name == short_name or \
           (_is_collection(kls.short_name) and short_name in kls.short_name):
            try:
                return kls(**params)
            except TypeError as e:
                spec = inspect.getargspec(kls.__init__)

                # try to give nice errors to the user if the params failed
                # to bind
                if 'unexpected' in str(e):
                    avail = join_quoted(spec.args[1:])
                    raise RuntimeError(
                        "%s's %s. Available params for this subclass are: %s."
                        % (short_name, str(e), avail))
                elif 'takes exactly' in str(e):
                    required = join_quoted(spec.args[1:-len(spec.defaults)])
                    raise RuntimeError(
                        "%s's %s. Required params for this subclass are %s."
                        % (short_name, str(e), required))
                elif 'takes at least' in str(e):
                    required = join_quoted(spec.args[1:-len(spec.defaults)])
                    optional = join_quoted(spec.args[-len(spec.defaults):])
                    raise RuntimeError(
                        "%s's %s. Required params for this subclass are: %s. "
                        "Optional params are: %s" % (
                            short_name, str(e), required, optional))
                # :(
                raise

    chain = itertools.chain.from_iterable(
        e.short_name if _is_collection(e.short_name) else [e.short_name]
        for e in sc)
    avail_names = ', '.join(str(n) for n in chain)
    raise ValueError('"%s" is not a recognized subclass. available names '
                     'are: %s' % (short_name, avail_names))
def init_subclass_by_name ( baseclass , short_name , params ) : sc = baseclass . __subclasses__ ( ) for kls in sc : if kls . short_name == short_name or ( _is_collection ( kls . short_name ) and short_name in kls . short_name ) : try : return kls ( * * params ) except TypeError as e : spec = inspect . getargspec ( kls . __init__ ) # try to give nice errors to the user if the params failed # to bind if 'unexpected' in str ( e ) : avail = join_quoted ( spec . args [ 1 : ] ) raise RuntimeError ( "%s's %s. Available params for this subclass are: %s." % ( short_name , str ( e ) , avail ) ) elif 'takes exactly' in str ( e ) : required = join_quoted ( spec . args [ 1 : - len ( spec . defaults ) ] ) raise RuntimeError ( "%s's %s. Required params for this subclass are %s." % ( short_name , str ( e ) , required ) ) elif 'takes at least' in str ( e ) : required = join_quoted ( spec . args [ 1 : - len ( spec . defaults ) ] ) optional = join_quoted ( spec . args [ - len ( spec . defaults ) : ] ) raise RuntimeError ( "%s's %s. Required params for this subclass are: %s. " "Optional params are: %s" % ( short_name , str ( e ) , required , optional ) ) # :( raise chain = itertools . chain . from_iterable ( e . short_name if _is_collection ( e . short_name ) else [ e . short_name ] for e in sc ) avail_names = ', ' . join ( str ( n ) for n in chain ) raise ValueError ( '"%s" is not a recognized subclass. available names ' 'are: %s' % ( short_name , avail_names ) )
Find the subclass, `kls` of baseclass with class attribute `short_name`
    that matches the supplied `short_name`, and then instantiate and return
    that class with:

        return kls(**params)

    This function also tries its best to catch any possible TypeErrors due
    to binding of the arguments, and rethrows them as nicely formatted
    RuntimeErrors that are suitable for showing to users.
Find the subclass kls of baseclass with class attribute short_name that matches the supplied short_name and then instantiate and return that class with :