You saw that, to define a decorator, you typically define a function returning a wrapper function. The wrapper function uses *args and **kwargs to pass on arguments to the decorated function. If you want your decorator to also take arguments, you need to nest the wrapper function inside another function. In this case, you usually end up with three return statements.
This difference becomes most important when there are several independent ways of extending functionality. In some object-oriented programming languages, classes cannot be created at runtime, and it is typically not possible to predict, at design time, what combinations of extensions will be needed. This would mean that a new class would have to be made for every possible combination. By contrast, decorators are objects, created at runtime, and can be combined on a per-use basis. The I/O Streams implementations of both Java and the .NET Framework incorporate the decorator pattern.
To calculate the tenth Fibonacci number, you should really only need to calculate the preceding Fibonacci numbers, but this implementation somehow needs a whopping 177 calculations. It gets worse quickly: 21891 calculations are needed for fibonacci(20) and almost 2.7 million calculations for the 30th number. This is because the code keeps recalculating Fibonacci numbers that are already known.
If working inside a person’s home, special attention will need to be paid to the different problems that can be encountered, such as those presented by pets and furniture. It is also essential to respect the private space of the client, and to work appropriately within it. If working for a construction firm, dangerous situations can be encountered, such as working at heights and employing the use of safety harnesses and ropes. Working outside brings with it its own hazards and difficulties, and the worker will need to plan for these accordingly through the types of clothing worn and the equipment used. The days can be long, and the hours can vary significantly. If self-employed, planning is essential to fit in as many jobs as is appropriate for the week, in order to avoid long spells of little work, or booking too many jobs into a short period of time. It is also possible that some jobs will require unsociable hours of work, such as working at the weekend. Although the profession is traditionally male dominated, more women are now being encouraged into the trade.
One of the other advantages of the decorator pattern is that wrapped objects can retain the type of the original object. As a result, you can use original and wrapped objects interchangeably, which is a significant advantage when your goal is to write flexible code. In this manner, you can easily extend the behavior of a particular object without modifying the original code.
Heller’s protagonist, Jim Stegner, is an unschooled but talented painter who struggles with drink, with womanizing, and with his temper. These traits have led him to be a killer, although Heller goes to great pains to let us know these acts are not premeditated. They’ve also, in accordance with these United States’ innate streak of violence, allowed him to be a cult figure - a talent around whom one feels it necessary to walk on eggshells. (For what it’s worth, this trait is to this reader and social observer the cause of a hollowness within the national psyche.) Stegner wants atonement for his acts, but he doesn’t know how to go about that. So Heller must allow Stegner to be the subject of retributive violence, which allows the painter, as might happen to a pre-adolescent child, to have atonement forced on him. Stegner is as a person and as a literary creation, a mess. Perhaps Heller intends him to be a faux Hemingway: hard drinking, bullying and a crybaby when those tables are turned on him. Stegner doesn’t seem to have the backbone about which an anti-hero’s fatal flaws can be built, though; he’s too much at the whims of fate for that. Heller tries to create philosophical depth for Stegner, but these attempts ring hollow. What he has created in Stegner, however, is a depiction of an instinctive artist, something the American psyche always seeks: talent and success untrammeled by subjecting that psyche to training and the lessons of culture and history. That Stegner is, in the end, a talented but pitiful figure, should tell the reader something very important: instinct that refuses at least a small measure of acculturation eventually become debased.
Some commonly used decorators that are even built-ins in Python are @classmethod, @staticmethod, and @property. The @classmethod and @staticmethod decorators are used to define methods inside a class namespace that are not connected to a particular instance of that class. The @property decorator is used to customize getters and setters for class attributes. Expand the box below for an example using these decorators.
A painter & decorator is responsible for preparing a surface and applying a range of finishes to it in response to the particular specifications of a job, paying close attention to detail to create a quality end product. The specific role of the painter & decorator is to prepare and decorate a particular surface in accordance with the wishes of the client. This will involve working on a wide variety of surfaces, including metal, wood, plaster and stone, and incorporating numerous materials, such as paint, varnish and wallpaper. The jobs involved depend upon the area that the painter & decorator works in. This can range from the industrial, specially-trained worker supplying skills for a large company, to the part-time, self-employed worker complementing a pension. A lot of the roles of the painter & decorator will come somewhere in between. If working for a larger construction firm, work can include more industrial-scale jobs, such as working as part of a team to prepare and paint the interior of a building or office. This will often involve specialist industrial techniques and larger equipment. If self-employed, this will normally include working independently on smaller jobs such as decorating private houses, schools, shops and other local buildings.
Landscape painting is a term that covers the depiction of natural scenery such as mountains, valleys, trees, rivers, and forests, and especially art where the main subject is a wide view, with its elements arranged into a coherent composition. In other works landscape backgrounds for figures can still form an important part of the work. Sky is almost always included in the view, and weather is often an element of the composition. Detailed landscapes as a distinct subject are not found in all artistic traditions, and develop when there is already a sophisticated tradition of representing other subjects. The two main traditions spring from Western painting and Chinese art, going back well over a thousand years in both cases.
The decorator pattern can be used to extend (decorate) the functionality of a certain object statically, or in some cases at run-time, independently of other instances of the same class, provided some groundwork is done at design time. This is achieved by designing a new Decorator class that wraps the original class. This wrapping could be achieved by the following sequence of steps:
I have been a Raoul Dufy fan for over ten years, searching out his paintings throughout museums in the US. I've been looking for information about him but come up empty. Found this dvd on Amazon. It was great. The documentary had terrific interviews and gorgeous images of his paintings. Even more it gave me a baseline for who is was and the scope of his work.
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Historically, the painter was responsible for the mixing of the paint; keeping a ready supply of pigments, oils, thinners and driers. The painter would use his experience to determine a suitable mixture depending on the nature of the job. In modern times, the painter is primarily responsible for preparation of the surface to be painted, such as patching holes in drywall, using masking tape and other protection on surfaces not to be painted, applying the paint and then cleaning up.
Painters apply paint, stain, varnish and other finishes to buildings and other structures. They select the right paint or finish for the surface to be covered, taking into account durability, ease of handling, method of application and customer's wishes. Painters first prepare the surfaces to be covered, so that the paint will adhere properly. This may require removing the old coat of paint by stripping, sanding, wire brushing, burning, scraping, or water and abrasive blasting. Painters also wash walls and trim to remove dirt and grease, fill nail holes and cracks, sandpaper rough spots and brush off dust. On new surfaces, they apply a primer or sealer to prepare the surface for the finish coat. Painters also mix paints and match colors, relying on knowledge of paint composition and color harmony. They also cover walls and ceilings with decorative wall coverings made of paper, vinyl or fabric.
In 1890, the Parisian painter Maurice Denis famously asserted: "Remember that a painting—before being a warhorse, a naked woman or some story or other—is essentially a flat surface covered with colors assembled in a certain order." Thus, many 20th-century developments in painting, such as Cubism, were reflections on the means of painting rather than on the external world—nature—which had previously been its core subject. Recent contributions to thinking about painting have been offered by the painter and writer Julian Bell. In his book What is Painting?, Bell discusses the development, through history, of the notion that paintings can express feelings and ideas. In Mirror of The World, Bell writes: