Barbara Liskov, Russell Atkinson, Toby Bloom, Eliot Moss, J. Craig Scha#ert, Robert Scheifler, and Alan Snyder. CLU reference manual, volume 114 of Lecture Notes in Computer Science. Springer-Verlag, 1981.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....generator has type ; similarly, the parameterized type vector used above has type int . In the presence of dependent function types, the type of all types allows the expression of parametric polymorphism [Strachey 1967, Reynolds 1983] which can be found in the programming languages CLU [Liskov et al. 1981], Ada [Ada 1980] Russell [Boehm et al. 1980, Donahue Demers 1985] and M[ Milner 1983] In tuitively, we can think of a polymorphic function as a function mapping types to values; a polymorphic function has a dependent type because the type of its result depends upon the value of its ....

Barbara Liskov, Russell Atkinson, Toby Bloom, Eliot Moss, J. Craig Schaffert, Robert Scheifier, and Alan Snyder. ULU Reference Manual. Volume 114 of Lecture Notes in Computer Science, Springer-Verlag, Berlin, 1981.

....the ESC specifications) for the sequence and streams packages discussed below are obtainable through the Modula 3 home page [18] 6. 1 Sequence Sequence is an interface of the standard Modula 3 library that implements a dynamically expandable array, much like the standard array type of CLU [15], allowing operations like add or remove an element from the high or low end of the array. This example is notable because ESC discovered bugs in publicly released code. The author of the code had been quite conscientious, building a detailed test suite. Unfortunately, this suite used sequences ....

B. Liskov, R. Atkinson, T. Bloom, E. Moss, C. Schaffert, R. Scheifler, and A. Snyder. CLU Reference Manual, volume 114 of Lecture Notes in Computer Science. Springer-Verlag, Berlin, 1981.

....concerns, which allows each part of the language design to be more highly polished. A prime example of this is the hide declaration in BeCecil. The hide declaration can hide information, and can even prevent impersonation, without any help from the type system. In this respect it differs from CLU [Liskov et al. 81] and from the abstype mechanism of Standard ML [Milner et al. 90] which achieves information hiding primarily by a difference between the types of objects as seen by the ADT implementation and its clients. BeCecil s hide declaration can be seen as a highly simplified and focussed version of ....

Barbara Liskov, Russell Atkinson, Toby Bloom, Eliot Moss, J. Craig Schaffert, Robert Scheifler, and Alan Snyder. CLU Reference Manual. Volume 114 of Lecture Notes in Computer Science, Springer-Verlag, NY, 1981.

....handling of many common cases. The smart pointer class developed in this paper also supports run time type queries. Such queries give programs the ability to ascertain the allocated type of an object at runtime, and is another feature offered in several high level languages (e.g. CLU [22], Modula 3 [21] The discussion is organized as follows: Section 2 discusses related work; Section 3 presents the garbage collection interface; Section 4 presents the template class framework and collection algorithm; Section 5 describes support for run time type queries; Section 6 presents some ....

B. Liskov; R. Atkinson; T. Bloom; E. Moss; C. Schaffert; R. Scheifler; and A. Snyder. CLU Reference Manual, volume 114 of Lecture Notes in Computer Science. SpringerVerlag, Berlin, 1981.

....two types, depending on what sort of facilities they have. First order module systems have only the trivial module facilities discussed so far: module creation, module naming, and module component extraction (M.x) Most traditional module systems are of this type. Examples include Ada [52] CLU [36], C [29] C [53] and Modula 2 [56] Higher order module systems, by contrast, have non trivial module manipulation facilities. I shall be concerned in this dissertation primarily with three such facilities: functors, submodules, and modules as first class values. Functors are functions mapping ....

Barbara Liskov, Russell Atkinson, et al. CLU Reference Manual, volume 114 of Lecture Notes in Computer Science. Springer-Verlag, 1981.

.... than might be classified as data abstractions, our work is motivated historically by several deficiencies we observed in languages that claimed to support extension via user defined abstract data types (ADTs) It seemed that the previous round of research in so called data abstraction languages [15][23] had left some unfinished business: 1. Heterogeneous (record like) type constructors cannot be defined. Particular types with a fixed set of fields of fixed name and type can be expressed, but 2 SEMANTICALLY SENSITIVE MACROPROCESSING there is no way to capture the commonality among all such ....

....(loop (cdr genfns) cons ( car genfns) statemap) fbinds) loop genfuns (empty list funbind) 8.3 Iterators An iterator is a function like object that yields not a single value, but a sequence of values generated on demand. Our formulation of iterators follows roughly that of CLU [15]. An iterator is constructed with the iterator special form. The argument list is identical in form to that of a lambda expression, but the result type must be explicitly indicated. The body of an iterator is an expression of type void. The body returns each value with the yield form, which may ....

Barbara Liskov et al. CLU Reference Manual, volume 114 of Lecture Notes in Computer Science. Springer-Verlag, 1981.

....A number of previous projects have used high level languages to implement real systems. These include the Cedar system, written in Mesa at Xerox PARC [26] the Topaz system, written in Modula 2 at DEC SRC [24, 32] the Symbolics and Xerox Lisp machines; the Swift system, written in CLU at MIT [9, 22]; and various real time and embedded systems written in Ada [36] Although several of these languages provide some of the same advantages over C that Standard ML does, none provides them all, as the following table indicates. Language First class Compile time Polymorphism Parameterized Formal ....

Barbara Liskov, Russell Atkinson, Toby Bloom, Eliot Moss, J. Craig Schaffert, Robert Scheifler, and Alan Snyder. CLU Reference Manual, volume 114 of Lecture Notes in Computer Science. Springer-Verlag, 1981.

....function, so the environment of the declaration of primes must contain a declaration of lt:Integer Integer Boolean. This constraint on type arguments resembles the property lists of parameters of the form type generator in Alphard [48, p. 38] or the where clause of a parameterized Clu cluster [33]. Note that the declaration of primes does not bind the current value of lt into primes. let insert = T: 3 lt: T T Boolean Delta v:T Delta l:SortedList T Delta : lt v (head l) in let lt = x:Integer Delta y:Integer Delta (gt x y) in in : insert[Integer] 7 primes : Because ....

Barbara Liskov, Russell Atkinson, Toby Bloom, Eliot Moss, J. Craig Schaffert, Robert Scheifler, and Alan Snyder. CLU Reference Manual, volume 114 of Lecture Notes in Computer Science. Springer-Verlag, 1981.

....of the root class of the hierarchy. Thus, an object belonging to a derived class could be substituted into any context in which an instance of the base class appears, without causing a type error in any subsequent execution of the code. This principle is known as Liskov s substitution principle [8]) Note that this hierarchy of classes can be as vast as the totality of all classes in the system if all classes are descendants of a unique root class (e.g. Smalltalk s Object, Eiffel s Any) We will now examine different uses of polymorphism that can affect the correctness of a program and ....

Barbara Liskov, Russel Atkinson, Toby Bloom, Eliot Mogs, J. Craig Schaffert, Robert Scheifler, and Alan Snyder. CLU Reference Manual, volume 114 of Lecture Notes in Computer Sciences. Springer Verlag, Berlin Heidelberg New York, 1981.

....int and y with type bool, and one type component, T. 1 First order module systems have only the trivial module facilities discussed so far: module creation, module naming, and module component extraction (M.x) Most traditional module systems are of this type. Examples include Ada [12] CLU [8], C [6] C [13] and Modula 2 [14] Higher order module systems, by contrast, have non trivial module manipulation facilities. I shall be concerned in this dissertation primarily with three such facilities: functors, submodules, and modules as first class values. Functors are functions mapping ....

Barbara Liskov, Russell Atkinson, et al. CLU Reference Manual, volume 114 of Lecture Notes in Computer Science. Springer-Verlag, 1981.

....language and the provision of annexes defining additional language capabilities for specific user communities. Other recent developments in programming language technology were not incorporated into Ada95 in keeping with the requirement to minimise disruption. These include: hybrid type systems[25] and dynamic binding, reflection[26] and persistence[1] While some of these technologies are immature and are yet to gain wider recognition, it is reasonable to anticipate changes before the next Ada language revision is due. This paper examines one of these emerging technologies, namely ....

B.H. Liskov, R. Atkinson, T. Bloom, E. Moss, J.C. Schaffert, R. Scheifler, and A. Synder. CLU Reference Manual, volume 114 of Lecture Notes in Computer Science. Springer--Verlag, Berlin Heidelberg, 1981.

....style suggests that there will be even fewer multi cycle non busy blocks. Thus it is plausible that properties (1) 3) will hold for ML programs. Toward the other end of the functional imperative spectrum, in a language that encourages a more imperative style than Scheme, e.g. CLU or Modula 3 [5, 23], object lifetimes are longer, but allocation rates are lower. Therefore programs in these languages may also have a large number of one cycle dynamic blocks. In this case, however, it is less clear that properties (1) and (3) will hold. A more imperative style may engender more multi cycle, ....

Barbara Liskov, Russell Atkinson, Toby Bloom, Eliot Moss, J. Craig Schaffert, Robert Scheifler, and Alan Snyder. CLU Reference Manual. Volume 114 of Lecture Notes in Computer Science, Springer-Verlag, Berlin, 1981.

....concerns, which allows each part of the language design to be more highly polished. A prime example of this is the hide declaration in BeCecil. The hide declaration can hide information, and can even prevent impersonation, without any help from the type system. In this respect it differs from CLU [Liskov et al. 81] and from the abstype mechanism of Standard ML [Milner et al. 90] which achieves information hiding primarily by a difference between the types of objects as seen by the ADT implementation and its clients. BeCecil s hide declaration can be seen as a highly simplified and focused version of the ....

Barbara Liskov, Russell Atkinson, Toby Bloom, Eliot Moss, J. Craig Schaffert, Robert Scheifler, and Alan Snyder. CLU Reference Manual. Volume 114 of Lecture Notes in Computer Science, Springer-Verlag, NY, 1981.

....Also commercially important is Enterprise Transaction Processing which allows interoperability between PCs, workstations, Unix based transaction systems and proprietary mainframe systems. These systems are open their facilities can be used by many different types of clients. 2. 2 Argus Argus [23, 24, 25] is an integrated programming language and system developed at the Massachusetts Institute of Technology to support the construction of reliable distributed programs on top of Unix. The Argus language, which is based on CLU [26] provides data abstraction facilities and is aimed at applications ....

B. Liskov. Argus, volume 448 of Lecture Notes in Computer Science, pages 108--114. Springer-Verlag, 1987.

....real systems. These include the Cedar system, written in Mesa at Xerox PARC [94] the Topaz system, written in Modula2 at DEC SRC [87, 121] the Trestle window system, written in Modula 3 at DEC SRC [19, 98, 82] the Symbolics and Xerox Lisp machines; the Swift system, written in CLU at MIT [24, 77]; and various real time and embedded systems written in Ada [132] Each of these languages provides some advantages over lower level languages such as C, but none provides all of the features found in Standard ML, as the following table summarizes. A solid bullet (ffl) indicates that the language ....

Barbara Liskov, Russell Atkinson, Toby Bloom, Eliot Moss, J. Craig Schaffert, Robert Scheifler, and Alan Snyder. CLU Reference Manual, volume 114 of Lecture Notes in Computer Science. Springer-Verlag, 1981.

....an instance of the type can be viewed as having that type or as having the implementation type. In the Timeofday example, the difference is important. Different languages have treated the distinction between the abstraction and the implementation in different ways. ffl Inside a Clu cluster [6], the declaration of an instance states which view applies. Two primitives called up and down can be used to convert between the views. ffl The Simula class [7] is essentially a record type. Since the only operations on a record are member selection and assignment, which can not be overloaded, ....

Barbara Liskov, Russell Atkinson, Toby Bloom, Eliot Moss, J. Craig Schaffert, Robert Scheifler, and Alan Snyder. CLU Reference Manual, volume 114 of Lecture Notes in Computer Science. Springer-Verlag, 1981.

....are easily obtained but other mechanisms may also be efficiently supported. A promising set of primitives has been suggested for ACTA [Ramamritham and Chrysanthis, 1992] and its use is being investigated as CACS [Stemple and Morrison, 1992] Other languages, such as Concurrent CLU [Liskov et al. 1981; Hamilton, 1984; Cooper and Hamilton, 1985] and Argus [Liskov, 1984] have explored different concurrency provision. The primitives for distribution have also to be chosen. Candidates may be found in Emerald [Black et al. 1987] Argus, Hermes [Strom et al. 1991] and Guide [Riveill, 1992] A ....

B. Liskov, R. Atkinson, T. Bloom, E. Moss, J.C. Schaffert, R. Scheifler, and A. Snyder. CLU Reference Manual, volume 114 of Lecture Notes in Computer Science. SpringerVerlag, Berlin, 1981.

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Barbara Liskov, Russell Atkinson, Toby Bloom, Eliot Moss, J. Craig Scha#ert, Robert Scheifler, and Alan Snyder. CLU reference manual, volume 114 of Lecture Notes in Computer Science. Springer-Verlag, 1981.

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B. Liskov, R. Atkinson, T. Bloom, E. Moss, J. C. Schaffert, R. Scheifler and A. Snyder, CLU Reference Manual, volume 114 of Lecture Notes in Computer Science, Springer-Verlag, 1981.

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Barbara Liskov, Russell Atkinson, Toby Bloom, Eliot Moss, J. Craig Schaffert, Robert Scheifler, and Alan Snyder. CLU Reference Manual, volume 114 of Lecture Notes in Computer Science. Springer-Verlag, 1981.

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Barbara Liskov, Russell Atkinson, Toby Bloom, Eliot Moss, J. Craig Schaffert, Robert Scheifler, and Alan Snyder. CLU Reference Manual, volume 114 of Lecture Note in Computer Science. Springer-Verlag, 1981.

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Barbara Liskov, Russell Atkinson, Toby Bloom, Eliot Moss, J. Craig Schaffert, Robert Scheifler, and Alan Snyder, CLU Reference Manual, volume 114 of Lecture Notes in Computer Science, Springer-Verlag, 1981.

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B. Liskov et al. CLU Reference Manual, volume 114 of Lecture Notes in Computer Science. Springer-Verlag, 1981.

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Barbara Liskov, Russell Atkinson, Toby Bloom, Eliot Moss, J. Craig Schaffert, Robert Scheifler, and Alan Snyder. CLU Reference Manual, volume 114 of Lecture Notes in Computer Science. Springer-Verlag, 1981.

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