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A collection of python coding utilities

Project description

Pytilities is a python3 utility library.


  • Aspect oriented programming:

    • Create Aspects to bundle advice

    • Apply advice to any attribute of an instance or all instances of a class. Can even be applied to attributes that don’t exist on the instance (i.e. create it). Can also be applied to any attribute of an object.

  • Event dispatching: Observer/Subject like event dispatching with wrappers for hiding events on dispatchers and combining dispatchers

  • Function overloading

  • Basic geometry: Vector, Rectangle classes

  • Various: cross platform infinity number, …




Advising is more KISS now. You map your advice in a plain dictionary, instead of using _advise. ‘*’ advice is now gone, instead you can use a special dictionary like object: pytilities.dictionary.FunctionMap. It allows for ‘*’ advice and more.

  • Aspect:

    • Added:

      • _advice_mappings: Mapping of (access, attribute_name) to advice. Note that ‘*’ is not a valid attribute_name, use FunctionMap instead of the old ‘*’ advice. If you use FunctionMap you should set _undefined_keys to True.

      • _undefined_keys: set to True if _advice_mappings provides infinite mappings

    • Removed:

      • _advise: use _advice_mappings instead

  • fixed a special case of invalid call advising, see pytilities.test.aop.calladvisespecialcase


  • View: the aspect did not correctly enable its aspect upon calling callables through the view


Delegation is more KISS now. The complex Profile class was removed in favor of plain dictionaries (and those of pytilities.dictionary). in_profile is replaced by the more flexible and KISS mapped.

  • mapped: adds an attribute to a mapping in a format that can be used as argument to DelegationAspect. You could also use it as a base for the _advice_mappings of your Aspect, …

  • mapped_class: required on a class for mapped to work

  • DelegationAspect:

    • no longer expects a Profile parameter, instead it expects a mapping of (access, source_attribute_name) to target_attribute_name; where access is ‘get’, ‘set’, or ‘delete’, as opposed to ‘r’, ‘w’, or ‘d’.

  • profile_carrier: use mapped_class instead

  • in_profile: use mapped instead

  • Profile: replaced by plain dictionaries (This is more flexible and KISS than the vague Profile interface)

pytilities.dictionary (new)

  • FunctionMap: A Mapping that uses a function to generate its values


  • DispatcherSwitch: now has its ‘delegation profile’ stored in public_mapping

  • Dispatcher: now has its ‘delegation profile’ stored in public_mapping and default_mapping


  • is_private: now only returns True for names matching __name or _SomeClass_name.

  • is_special: returned False on special attributes



Made aop more KISS so it’s easier to understand, use (and maintain):

  • Distinction between class and instance advice may now be forgotten, there’s only advice. Classes act as wildcards now, e.g. aspect.apply(Class) means apply to all instances of Class and Class itself.

  • You can now apply an aspect to all instances from a class and then exclude an instance from that advice by unapplying it afterwards.

Improved test coverage (less bugs now).

  • advisor.get_applied_aspects(obj)

  • AOPException

  • yield suppress_aspect: context manager that prevents the current aspect from having its advice executed till the end of the context

  • yield advised_attribute: replaces (yield name, yield advised).

  • yield advised_instance: returns the instance to which the aspect was applied (or the class in case the advised is a static/class method)

  • Aspect:

    • _advise: You can no longer advise a member more than once. This includes trying to advise ‘*’ and some regular member at the same time. (this makes Aspect more KISS, you can workaround this limitation using multiple aspects)

    • is_enabled: now returns False for objects to which it is not applied

    • apply: now applies the aspect to all instances of cls and cls itself when supplied a class

    • unapply: now unapplies the aspect on all instances of cls and cls itself when supplied a class

    • unapply_all: now unapplies all aspects on all instances of cls and cls itself when supplied a class

    • is_applied: returns True, if given object is in advisor.get_applied_aspects(obj)

  • yield name: Removed in favor of the clearer yield advised_attribute

  • yield advised: Removed in favor of the clearer yield advised_attribute

  • yield obj: Removed in favor of the clearer yield advised_instance

  • Support for advising modules: It has become too hard too maintain this feature while there are decent workarounds for this lack:

    • Put your functions in a class with staticmethods or classmethods

    • Or use the singleton pattern.

    And then apply the aspect to that class.

  • advisor.unapply_all: forgot to implement it

  • yield advised returned the wrong callable on call access

  • When trying to get an unexisting attribute after having had advice applied and unapplied to it, the object would no longer throw AttributeError on get access

  • Aspect.enable and Aspect.disable had no effect


  • ImmutableAttributeException

  • ImmutableAspect: as required by the fix (see below): - it can now only be applied on objects with AOPMeta as metaclass - it now raises ImmutableAttributeException on attempts to mutate

  • create_view: did not enable its aspect on access

  • ImmutableAspect: it only worked for detecting change on setters, it now detects every change.


Added and refactored tests

  • DereferencedBoundDescriptor: like BoundDescriptor but takes 2 descriptors as args that are dereferenced(/read/getted) on each call.

  • BoundDescriptor:

    • special_dereference parameter was removed

    • instance arg will no longer be dereferenced when a descriptor arg is passed

    If you need any of the two above, use DereferencedBoundDescriptor. (splitting the class in two like this would make it more intuitive to use)


Included in release so that unit tests can be run


The library moved to python3, older python versions are no longer supported. There a lot of changes, breaking quite a bit of the previous interface. All changes are listed below.


  • get_annotations: gets annotations of an object, allows to add new ones, …

  • get_attr_name, get_attr_value, has_attr_name, has_attr_value: gets an attribute, bypassing regular lookup (no descriptor.__get__, …, does support inheritance though)

  • AttributeCollection, AttributeCollectionBase: use aop instead (see User Guide)

  • mangle:

    • You can now pass an instance as well.

    • Small fix involving class names that start with a ‘_’


This package brings aspect oriented language features to python (in a handy format). You can apply advice on classes and instances, using aspects that can be applied and unapplied, enabled, disabled, …

  • advisor: singleton that aspects use to give advice (you shouldn’t use this directly, derive from Aspect and use its methods instead)

  • proceed, return_close, return_, arguments, advised, obj, name yields for advice functions

  • Aspect: base class to write your own aspects with (you are not required to use this, but it is greatly recommended)

  • AOPMeta: classes that are given * advice require to have AOPMeta as metaclass, other advised classes may benefit from this metaclass as it reduces memory usage


  • DelegationAspect: delegate attributes from a source instance/cls to a target. Only supports direct mappings (mappings with the same source and target attributes).

  • in_profile, profile_carrier: used to more easily place some profiles on a class

  • Profile

  • Delegator, DelegatorFactory: use delegate or any of the other possibilities listed in the User Guide instead

  • delegator_factory: use profile_carrier instead.

  • delegated: use in_profile instead.

  • delegate: use DelegationAspect instead. You may want to read about AOP in the user guide first

pytilities.descriptors (new)

  • AttributeDescriptor: turns a regular attribute into a descriptor

  • DereferencedDescriptor: returns inner_desc.get.get, sets inner_desc.get.set, …

  • BoundDescriptor: binds an instance to a descriptor, much like bound methods

  • RestrictedDescriptor: strip of the get, set or del of a descriptor


  • dispatcher, dispatcherswitch (decorators): normally you’d send events from an aspect as it’s a crosscutting concern, so these no longer have to be supported. Use a custom Aspect + DelegationAspect instead.


  • DiscreteVector, DiscreteRectangle: A Vector/Rectangle with a discrete coordinate space. All aspects and views for Vector/Rectangle work on these as well.

  • verbose_rectangle_aspect, verbose_vector_aspect: Aspects to make a Rectangle/Vector send out (change) events.

  • ImmutableRectangle, ImmutableVector: immutable views of a Rectangle/Vector

  • immutable_rectangle_aspect, immutable_vector_aspect: makes a Rectangle/Vector immutable

  • Vector, Rectangle: Due to a change in int division mechanisms in python3, these classes will always operate with a continuous coordinate space. I.e if your vector has coords (3, 1), then when divided by 2 they become (1.5, 0.5) and not (1, 0) as they used to be in previous versions. Use DiscreteVector and DiscreteRectangle instead, to get similar behaviour back.

  • Vector, DiscreteVector: have an extra overload for assign that accepts (x,y) as args

  • BoundVector: use Vector directly instead (use its bound properties overload)

  • VerboseVector: make a Vector and do verbose_vector_aspect.apply(v) instead. This works for DiscreteVectors as well.

  • VerboseRectangle: make a Rectangle and do verbose_rectangle_aspect.apply(v) instead. This works for DiscreteVectors as well.


  • overloaded: its returned function now has a process_args method as well

  • Parameter: its ctor was incorrectly overloaded (ironically). This has been fixed, its overloads changed slightly because of this.

pytilities.infinity (new)

Provides a cross-platform alternative to float(‘inf’).

  • infinity, negative_infinity, nan

  • is_infinity


  • is_public, is_protected, is_private, is_special: attribute name checks


  • Mangle, mangling and event.dispatcher: fixed a slight name clash

  • Overhauled testing, it is now easier to use

  • Removed inheritance feature of DelegatorFactory, it was too vague

  • Removed __init_delegation_profiles, there are other ways to achieve the same thing

  • Changed the DelegatorFactory interface so that it is hopefully more intuitive to use

  • Added all set operators to delegation.Profile

  • Added more tests and fixed some docstrings

  • RestrictedDispatcher: Made allow and disallow mutually exclusive. It made no sense to specify both


  • Added html reference documentation


  • Added, which allows running unit tests

  • Added the types package (forgot this in last release)


  • Fixed: the last release wouldn’t parse


  • Initial release: delegation tools, events, overloading, …

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