Source code for traits.trait_errors
# (C) Copyright 2005-2022 Enthought, Inc., Austin, TX
# All rights reserved.
#
# This software is provided without warranty under the terms of the BSD
# license included in LICENSE.txt and may be redistributed only under
# the conditions described in the aforementioned license. The license
# is also available online at http://www.enthought.com/licenses/BSD.txt
#
# Thanks for using Enthought open source!
""" Defines the standard exceptions raised by the Traits package.
"""
from .trait_base import class_of
[docs]def repr_type(obj):
""" Return a string representation of a value and its type for readable
error messages.
"""
the_type = type(obj)
msg = "%r %r" % (obj, the_type)
return msg
[docs]class TraitError(Exception):
def __init__(self, args=None, name=None, info=None, value=None):
if name is None:
# If the given args is not a tuple then assume that the user
# intended it to be the single item in a one-element tuple.
if not isinstance(args, tuple):
args = (args,)
self.args = args
else:
# Save the information, in case the 'args' object is not the
# correct one, and we need to regenerate the message later:
self.name = name
self.info = info
self.value = value
self.desc = None
self.prefix = "The"
self.set_desc(None, args)
def set_desc(self, desc, object=None):
if hasattr(self, "desc"):
if desc is not None:
self.desc = desc
if object is not None:
self.object = object
self.set_args()
def set_prefix(self, prefix):
if hasattr(self, "prefix"):
self.prefix = prefix
self.set_args()
def set_args(self):
if self.desc is None:
extra = ""
else:
extra = " specifies %s and" % self.desc
obj = getattr(self, "object", None)
# Note: self.args must be a tuple so be sure to leave the trailing
# commas.
if obj is not None:
self.args = (
(
"%s '%s' trait of %s instance%s must be %s, "
"but a value of %s was specified."
% (
self.prefix,
self.name,
class_of(obj),
extra,
self.info,
repr_type(self.value),
)
),
)
else:
self.args = (
(
"%s '%s' trait%s must be %s, but a value of %s was "
"specified."
% (
self.prefix,
self.name,
extra,
self.info,
repr_type(self.value),
)
),
)
[docs]class TraitNotificationError(Exception):
pass
[docs]class DelegationError(TraitError):
def __init__(self, args):
# .args must be a tuple.
self.args = (args,)