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:
“Today the young actors regard their environment with rage and disgust. They regard their Master not as disciples regard their Master, but as slaves regard their Master.”
—Judith Malina (b. 1926)
“The poorest children in a community now find the beneficent kindergarten open to them from the age of two-and-a-half to six years. Too young heretofore to be eligible to any public school, they have acquired in their babyhood the vicious tendencies of their own depraved neighborhoods; and to their environment at that tender age had been due the loss of decency and self-respect that no after example of education has been able to restore to them.”
—Virginia Thrall Smith (1836–1903)