Using functions with "action-at-a-distance" through sys.settraceback may be okay for an obscure feature that can't be had any other way yet doesn't merit changes to the language, but that's not the situation for decorators. The widely held view here is that decorators need to be added as a syntactic feature to avoid the problems with the postfix notation used in 2.2 and 2.3. Decorators are slated to be an important new language feature and their design needs to be forward-looking, not constrained by what can be implemented in 2.3.
Overall unfamiliarity with the concept. For people who have a passing acquaintance with algebra (or even basic arithmetic) or have used at least one other programming language, much of Python is intuitive. Very few people will have had any experience with the decorator concept before encountering it in Python. There's just no strong preexisting meme that captures the concept.
Aesthetics is the study of art and beauty; it was an important issue for 18th- and 19th-century philosophers such as Kant and Hegel. Classical philosophers like Plato and Aristotle also theorized about art and painting in particular. Plato disregarded painters (as well as sculptors) in his philosophical system; he maintained that painting cannot depict the truth—it is a copy of reality (a shadow of the world of ideas) and is nothing but a craft, similar to shoemaking or iron casting. By the time of Leonardo, painting had become a closer representation of the truth than painting was in Ancient Greece. Leonardo da Vinci, on the contrary, said that "Italian: La Pittura è cosa mentale" ("English: painting is a thing of the mind"). Kant distinguished between Beauty and the Sublime, in terms that clearly gave priority to the former. Although he did not refer to painting in particular, this concept was taken up by painters such as J.M.W. Turner and Caspar David Friedrich.
Enforcement of this Act by the Painter-Stainers Company was sought up until the early 19th century, with master painters gathering irregularly to decide the fees that a journeyman could charge, and also instigating an early version of a job centre in 1769, advertising in the London newspapers a "house of call" system to advertise for journeymen and also for journeymen to advertise for work. The guild's power in setting the fee a journeyman could charge was eventually overturned by law in 1827, and the period after this saw the guild's power diminish, along with that of the other guilds; the guilds were superseded by trade unions, with the Operative United Painters' Union forming sometime around 1831.
Did you get it? We just applied the previously learned principles. This is exactly what the decorators do in Python! They wrap a function and modify its behaviour in one way or the another. Now you might be wondering that we did not use the @ anywhere in our code? That is just a short way of making up a decorated function. Here is how we could have run the previous code sample using @.
Acrylic paint is fast drying paint containing pigment suspension in acrylic polymer emulsion. Acrylic paints can be diluted with water, but become water-resistant when dry. Depending on how much the paint is diluted (with water) or modified with acrylic gels, media, or pastes, the finished acrylic painting can resemble a watercolor or an oil painting, or have its own unique characteristics not attainable with other media. The main practical difference between most acrylics and oil paints is the inherent drying time. Oils allow for more time to blend colors and apply even glazes over under-paintings. This slow drying aspect of oil can be seen as an advantage for certain techniques, but may also impede the artist's ability to work quickly.
Syntactic constraints. Python is a syntactically simple language with fairly strong constraints on what can and can't be done without "messing things up" (both visually and with regards to the language parser). There's no obvious way to structure this information so that people new to the concept will think, "Oh yeah, I know what you're doing." The best that seems possible is to keep new users from creating a wildly incorrect mental model of what the syntax means.
The decorator pattern is a design pattern that allows you to wrap an object such that it will appear to execute a given behavior in many different ways at different points in program execution. This is especially useful when you want an object to have different behaviors at but are unable to mutate the object. The decorator pattern is a useful way to implement dynamic behavior without needing an extended inheritance-based class hierarchy. To use the decorator pattern you need four elements: a component interface; a concrete component; a decorator abstraction; and, a concrete decorator. The interface sets the contract for both component and decorator behavior, the decorator abstraction contains a pointer to some concrete component, and the concrete decorators wrap a concrete component and override behavior if desired.
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.
Modifying classes in this fashion is also possible, though the benefits are not as immediately apparent. Almost certainly, anything which could be done with class decorators could be done using metaclasses, but using metaclasses is sufficiently obscure that there is some attraction to having an easier way to make simple modifications to classes. For Python 2.4, only function/method decorators are being added.
Modern and Contemporary Art has moved away from the historic value of craft and documentation in favour of concept, leading some to say, in the 1960s, that painting as a serious art form is dead.[clarification needed] This has not deterred the majority of living painters from continuing to practice painting either as whole or part of their work. The vitality and versatility of painting in the 21st century defies the previous "declarations" of its demise. In an epoch characterized by the idea of pluralism, there is no consensus as to a representative style of the age. Artists continue to make important works of art in a wide variety of styles and aesthetic temperaments—their merits are left to the public and the marketplace to judge.