The Environment
One feature of Self is that it is based on the same sort of virtual machine system that earlier Smalltalk systems used. That is, programs are not stand-alone entities as they are in languages such as C, but need their entire memory environment in order to run. This requires that applications be shipped in chunks of saved memory known as snapshots or images. One disadvantage of this approach is that images are sometimes large and unwieldy; however, debugging an image is often simpler than debugging traditional programs because the runtime state is easier to inspect and modify. (Interestingly, the difference between source-based and image-based development is analogous to the difference between class-based and prototypical object-oriented programming.)
In addition, the environment is tailored to the rapid and continual change of the objects in the system. Refactoring a "class" design is as simple as dragging methods out of the existing ancestors into new ones. Simple tasks like test methods can be handled by making a copy, dragging the method into the copy, then changing it. Unlike traditional systems, only the changed object has the new code, and nothing has to be rebuilt in order to test it. If the method works, it can simply be dragged back into the ancestor.
Read more about this topic: Self (programming Language)
Famous quotes containing the word environment:
“Autonomy means women defining themselves and the values by which they will live, and beginning to think of institutional arrangements which will order their environment in line with their needs.... Autonomy means moving out from a world in which one is born to marginality, to a past without meaning, and a future determined by others—into a world in which one acts and chooses, aware of a meaningful past and free to shape one’s future.”
—Gerda Lerner (b. 1920)
“People between twenty and forty are not sympathetic. The child has the capacity to do but it can’t know. It only knows when it is no longer able to do—after forty. Between twenty and forty the will of the child to do gets stronger, more dangerous, but it has not begun to learn to know yet. Since his capacity to do is forced into channels of evil through environment and pressures, man is strong before he is moral. The world’s anguish is caused by people between twenty and forty.”
—William Faulkner (1897–1962)