An overview of the object oriented language sather
The invariant must hold in a. This prevents such variables from being put into registers and can be detrimental to performance.
We point out the similarities and the differences between the three languages. Parameterized classes allow flexible classes to be written and used in a variety of situations without sacrificing either type safety or efficiency.
This is way to combine the functionality of ADT's and inheritance to obtain what wrlpile-time checked capabilities by Jones and Liskov in the late seventies .
Sather is able to statically check programs for type correctness. The main important use seems to be run-time code instrumentation. The profiler collects execution statistics for program optimization. It also guarantees reasonable properties of fairness when several threads are contending for the same lock.
Statically-checked strong typing helps the Sather compiler to generate more efficient code because it has more information. This makes conflict resolution imperative and low-level.
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The libraries are covered by an unrestrictive license which encourages the sharing of software and crediting authors without prohibiting use in proprietary and commercial projects. In Sather, which stresses implementation inheritance, descendents are not constrained by the semantics of their parents. Thus each descendent class and each set of parameterizations in a parameterized class generates its own version of the routines it uses. There is a tension between subtypes and inheritance. Programs with this bug use up more and more memory until they crash. Sather extends the flexibility of its extensible type system to foreign types. Murer, S.
The addition of a legal call to a parent could invalidate an existing remote descendent. Among the advantages of this distinction are the explicit control of typing,non-dispatched caJls, inlining and other optimizations.
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Lim, F. Steele Jr. Listing 4 shows how to set the elements of an array to successive integers and then how to double them. When an iter quits, it terminates the loop in which it appears. This is a routine which makes sense for generic polygons but does not make sense for triangles, squares, etc. On the one hand, this unfolding allows optimizing self calls and calls to classes without decendents. The performance consequences of abstract types were studied by comparing a version of the compiler in which all calls were dispatched to the standard version Lim and Stolcke, We do not believe in single language approaches. Each feature name is assigned a unique integer value. When it is called in the next iteration of the loop, execution begins at the statement following the "yield". Certain conditions are described as fatal errors.
Each class may define many sorts of iterators, whereas a traditional approach requires a different yet intimately coupled class for each kind of iteration over the major class.
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