Borning, A.H., Ingalls, D.H., A Type Declaration and Inference System for Smalltalk. In Proc. ACM Symp. Principles of Programming Languages, ACM Press, 1982, pp. 133--141.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....the initialize method. Such an approach alone is not really convincing because the initialize method can be implemented using a composed method [Bec97] resulting in no type information. Static type inference techniques have been developed for dynamically typed languages like Self and Smalltalk [BI82, Suz81, PC94, Age96, Joh86]. However, those techniques are complex to implement and require a lot of computation power. Type inference techniquesfor compiler implementation must provide strong optimizations and distinguish between Bat. Essi 650 Route des Colles. B.P. 145. 06903 Sophia Antipolis Cedex, France (blay, ....

Alan Borning and Dan Ingalls. A type declaration and inference system for smalltalk. In ACM Symposium on Principles of Programming Languages, 1982.

....if it is useful to study new type systems for OO, when the most used OO languages, C [Str97] Simula [BDMN73] and Java [AG96] too, are all typed. One reason could be that significant historical type systems, such that the one of Simula, or the one developed for a typed version of Smalltalk [BI82], are not completely type safe. A language is not type safe when it is possible to write programs that result well typed but that produce runtime errors, in principle forbidden by the type system. There have been discussions about the type safety of Eiffel [Mey92] for which runtime adjustments ....

A.H. Borning and D.H. Ingalls. A Type Declaration and Inference System for Smalltalk. In Proc. of ACM Symp. POPL, pages 133--141. ACM Press, 1982.

....process like objects. Quicktalk: A compilable dialect of Smalltalk, from Tektronix. Ball86] Simula: A simulation language with object classes. Birt73] Smalltalk: Programming language and environment from Xerox PARC. Some references detail experinces with implementation details. [Atki86 BYTE81 Born82a Born82b Caud86 Deco86 Deut84 Gold80b Gold83 Gold84 John86 Kaeh86 Kras83 Pasc86 Tesl81 Vegd86] Smallworld: Smalltalk descendent from IBM Yorktown. La#85] Spool: A Prolog based object oriented language from IBM Japan. Fuku86] Squeak: An object oriented language for communicating with mice. Card85a] Strobe: A language providing object oriented support for Lisp. See also Impulse 86. ....

A.H. Borning and D.H.H. Ingalls, "A Type Declaration and Inference System for Smalltalk", 9th Symposium on Principles of Programming Languages, Albuquerque, NM, 1982.

....Function specialization allows the evolution and modification of a recursive function without physically changing the original. 25 3. 4 Data Type Inheritance The types found in programming languages like Pascal may also be constructed using inheritance, a possibility noted by Borning and Ingalls [4]. Data structure inheritance allows an existing recursive data structure to be specialized, typically by adding fields to the record representing a node in the recursive structure. All levels of this data structure are specialized, because recursive pointers refer to the specialized definition. ....

A. H. Borning and D. H. Ingalls. A type declaration and inference system for smalltalk. In Proc. of the ACM Symp. on Principles of Programming Languages, pages 133--141. ACM, 1982.

.... Object Oriented I linguaggi di programmazione Object Oriented possono essere classificati, in accordo al modello sottostante, come linguaggi basati sulle Classi (class based) o basati sul concetto di Delegati (delegation based) Nei linguaggi basati sulle classi, come ad esempio SmallTalk [BI82, GR83] e C [ES90] l implementazione di un oggetto e specificata da un template , cio e la sua classe, ed ogni oggetto e creato per istanza dalla sua classe. I linguaggi basati sul concetto di delegati, come ad esempio Self [US87] sono costruiti sull idea che gli oggetti sono creati ....

A.H. Borning and D.H. Ingalls. A Type Declaration and Inference System for Smalltalk. In Proc. of the 9th ACM Symposium on Principles of Programming Languages, pages 133--141. The ACM Press, 1982.

....4 is not available. This implies that a subclass will inherit the most specific definition of a property in a hierarchy. Our approach to the definition based overriding is shared by most classical object oriented models including O 2 [17] Orion [15] Gemstone [18] C [22] Smalltalk [5], etc. However, in the case of a multiple inheritance, a subclass may be required to inherit a property from more than one superclasses and an inconsistency may result due to the di#erence in implementation of the method or the signature. This is known as inheritance conflict or ambiguity. The ....

....do not. We exploit the syntactic properties of programs, such as locality of method clauses, to determine the inheritability of these clauses using static compilation. This is possible because we adopt a static overriding approach similar to many imperative languages such as C [22] Smalltalk [5], and object oriented databases such as Gemstone [18] Orion [15] and O 2 [17] Although the inheritability function #m uses negative 138 information, it is easy to see that the concepts of rule locality and inheritability of clauses help eliminate the need for stratification, and thus help ....

A. H. Borning and D. H. Ingalls. A type declaration and inference system for Smalltalk. In Proc. of the ACM Symposium on Principles of Programming Languages, pages 133--141, 1982.

....compiler. 1 Introduction There has been a lot of interest recently in type systems for object oriented programming languages [CW85, DT88] Since Smalltalk was one of the earliest object oriented languages, it is not surprising that there have been several attempts to provide a type system for it [Suz81, BI82]. Unfortunately, none of the attempts have been completely successful [Joh86] In particular, none of the proposed type systems are both type safe and capable of type checking most common Smalltalk programs. Smalltalk violates many of the assumptions on which most objectoriented type systems are ....

A. H. Borning and D. H. H. Ingalls. A type declaration and inference system for Smalltalk. In Conference Record of the Ninth Annual ACM Symposium on Principles of Programming Languages, pages 133--139, 1982.

....have attempt to included many object oriented type inference projects that support the software engineering aspects of type inference, this list is almost certainly incomplete. 3.1. Early Work Alan Borning and Dan Ingalls were among the first to add type inference to an object oriented language [Borning and Ingalls, 1982]. They created a type type A; type B; type C; type D; signature foo(A,B) A; signature foo(C,D) C; method bar(arg1, arg2) return foo(arg1, arg2) declaration and inference system for Smalltalk 80. Although their primary goal was to allow the static typechecking of Smalltalk code, their ....

Alan H. Borning and Dan H. Ingalls. A Type Declaration and Inference System for Smalltalk, Conference Record of the Ninth Annual ACM Symposium on Principles of Programming Languages, pp. 133-141, Albuquerque, New Mexico, January 1982.

....object oriented languages is an active field of research within the last fifteen years, and there is a broad variety of approaches that have been proposed for it. In spirit most closely related to our approach, though not really comparable, are the type inference based approaches as e.g. in [Ag1, Ag2, BI, GJ, Jo, OPS, PS1, PS2, Su], and the data flow analysis (DFA) based approaches as e.g. in [PC1, PC2, VHU] They characterize the state of the art of the type inference and the data flow analysis based approaches, respectively. The type inference approaches of [Ag2, OPS, PS2] improve on previous approaches of this group ....

Borning, A. H., and Ingalls, D. H. H. A type declaration and inference system for Smalltalk. In Conference Record of the 9th International Symposium on Principles of Programming Languages (POPL'82) (Albuquerque, New Mexico), 1982, 133 - 141.

....and Schiffman s seminal paper on an efficient implementation of Smalltalk 80 [DS84] and as a result Suzuki and Terada s work was put somewhat in the shade. 5 Smalltalk can, however, be considered dynamically typed (see [Bar89] 2.3) CHAPTER 2. WHY ANALYSE PROGRAMS 21 Borning and Ingalls [BI82] developed a type declaration system for Smalltalk 80 to provide programmer feedback. However their system was ultimately flawed due to a badly designed type structure. A description of this system may also be found in [Bar89] The idea of adding redundant type declarations was taken up by ....

Alan H. Borning and Daniel H. H. Ingalls. A type declaration and inference system for Smalltalk. In Proceedings of the Ninth ACM Symposium on the Principles of Programming Languages, pages 133--141, Albuquerque, New Mexico, 1982.

....compiler statically predicts types and generates optimized code including runtime type tests to verify its prediction. This optimization technique can be used in SPiCE. Type inferencing Identifying the class of the receiver, i.e. type inferencing, is very di#cult in Smalltalk [ Suzuki 1981; Borning and Ingalls 1982 ] However, recently the cartesian product algorithm [ Agesen 1995 ] has been proposed. It can infer concrete types of object oriented programs, and by incorporating it into the Self compiler, it can in line over 95 of all message sends. Since the Self language and 70 environment is very ....

A. H. Borning and D. H. H. Ingalls: "A Type Declaration and Inference System for Smalltalk," in Conference Record of the Ninth Annual ACM Symposium on Principles of Programming Languages, pp. 133--139, January 1982.

....of modern software systems. These systems also provide a black box capability by hiding implementation details which is useful for practical large software development and their maintenance. Inspired by these ideas, several successful procedural languages, such as loosely typed Smalltalk [16] and strongly typed C [72] have emerged. Motivated by the success of these languages, the logic programming community has expended their best effort in devising an object oriented logic programming language in the recent years. Despite all the efforts, only limited success has been achieved ....

A. H. Borning and D. H. Ingalls. A type declaration and inference system for smalltalk. In Proc. of the ACM Symposium on Principles of Programming Languages, pages 133--141, 1982.

....is described with examples. The basic constructs are explained first to specify simple types, and they are extended to define more complex types. A type is an abstraction of several Smalltalk classes, characterized by a behavioral specification. The term type here is similar to those found in [3, 14] and interfaces in [4] A type specification can be implemented by more than one Smalltalk classes. For example, type Boolean is implemented by three Smalltalk classes, Boolean, True, and False. Specifying programs in terms of types, not in Smalltalk classes, allows one to structure ....

....is appropriate to send the message value only to a block taking no arguments, the message value: to a block taking one argument, the message value:value: to a block taking two arguments, and so on. This leads us to specify blocks by a family of types according to their numbers of input arguments [3]. Since the same block can take and return objects of different types, it would be appropriate to parameterize specifications of blocks according to their input and return types. One approach to the block type specifications is to view blocks as mappings on execution states. The evaluation of a ....

[Article contains additional citation context not shown here]

Borning, A. H., and D. H. H. Ingalls, A Type Declaration and Inference System for Smalltalk. In Conference Record of the Ninth Annual ACM Symposium on Principles of Programming Languages, Albuquerque, New Mexico, pages 133-- 141. ACM, Jan. 1982.

....language with object oriented features, C [Str86, ES90] are both typed, it is natural to ask why new or different type systems are needed. One problem is that historically significant type systems, such as the Simula type system and the one developed by Borning and Ingalls for Smalltalk [BI82] have had significant type insecurities. This means that a well typed program could, when executed, send a message to an object that has no method for responding to the message a situation that the type system was intended to prevent. The second and less clear cut problem is that there remain ....

A.H. Borning and D.H. Ingalls. A type declaration and inference system for Smalltalk. In ACM Symp. Principles of Programming Languages, pages 133-- 141, 1982.

....language with object oriented features, C [Str86, ES90] are both typed, it is natural to ask why new or different type systems are needed. One problem is that historically significant type systems, such as the Simula type system and the one developed by Borning and Ingalls for Smalltalk [BI82] have had significant type insecurities. This means that a well typed program could, when executed, send a message to an object that has no method for responding to the message a situation that the type system was intended to prevent. The second and less clear cut problem is that there remain ....

A.H. Borning and D.H. Ingalls. A type declaration and inference system for Smalltalk. In ACM Symp. Principles of Programming Languages, pages 133--141, 1982.

.... and Self that strive for extreme code reusability through various forms of polymorphism have traditionally foregone the benefits of static typing in favor of the more arbitrary flexibility of dynamic typing (where all types are verified on the fly during execution) A number of attempts [Suz81, BI82, GJ90] have been made to retrofit a static type system to Smalltalk. Most of these efforts have been significantly complicated by the extraordinary requirement that they typecheck large bodies of existing Smalltalk code that were written without any notion of static type safety in mind. This paper ....

....to preserve. 6 Related Work 6.1 Typechecking Smalltalk There have been several efforts to introduce static typechecking (or type inference) to Smalltalk. These efforts have had differing objectives, resulting in different approaches to the problem. Early efforts met with limited success [Suz81, BI82]. TS [JGZ88, Gra89, GJ90] is geared toward typechecking Smalltalk in its entirety, and toward optimization. The scope of Strongtalk is less ambitious in this respect. Certain Smalltalk programs that are accepted by TS will not be accepted by Strongtalk. The advantage of our approach is the ....

Alan H. Borning and D. H. Ingalls. A type declaration and inference system for Smalltalk. In Proc. of the ACM Symp. on Principles of Programming Languages, pages 133--141. Association for Computing Machinery, 1982.

....language this is the only run time error that can occur. The purpose of a type system is to allow the programmer to annotate programs with information about which methods are available in a given object, and to allow the compiler to guarantee the the error messageNotUnderstood will never occur [4, 9]. The latter immediately enables compile time optimizations because a number of checks need not be inserted into the code. In Smalltalk, any object can be assigned to any variable. Message sending is implemented by late binding, i.e. the message send is dynamically bound to an implementation ....

Alan H. Borning and Daniel H. H. Ingalls. A type declaration and inference system for Smalltalk. In Ninth Symposium on Principles of Programming Languages, pages 133--141, 1982.

....have a definition for it, bringing the system to an inelegant halt. We have solved both of these problems by adding a static type system to Smalltalk. The resulting type system is quite different from those proposed by others designing type systems for object oriented programming languages (e.g. [Suz81, BI82, Car84, BHJL86]) This is mainly because Smalltalk has a unique combination of useful features that no other language has. In general, a static type system has many uses: ffl it provides information that a compiler can use during code optimization to produce a more efficient program, 2 An ad hoc comparison of ....

....to the particular point being addressed. Type systems that do include parameterized types often use the functional version of the subtype relation, either because they are designed for functional languages [CW85, Wan87, Car88] or because they, incorrectly, take a functional view of Smalltalk [BI82]. 1.3.1 Type Systems for Object Oriented Programming Languages Much of modern type system research is based on the work of Milner who published the first description of a polymorphic type inference algorithm [Mil78] Other important contributions from Milner s research include the use of ....

[Article contains additional citation context not shown here]

A. H. Borning and D. H. H. Ingalls. A type declaration and inference system for Smalltalk. In Conference Record of the Ninth Annual ACM Symposium on Principles of Programming Languages, pages 133--139, 1982.

....simultaneously. The class phonebook can now be obtained through a type substitution of text for arg and integer for res. 8 Heterogeneous Variables Assignments between unequal types were not needed to construct generic classes. Actually, most parts of a program do not need such assignments [1]. However, they are clearly required to build heterogeneous data structures. This suggests that genericity and heterogeneity are independent issues. To obtain a comprehensive language, we now introduce heterogeneous variables, i.e. variables which may hold not only instances of the declared ....

....implementations in such situations. In the following section we give the complete typecheck rules which also considers heterogeneous expressions. 9 Type checking The traditional purpose of type checking in objectoriented languages is to ensure that all messages to objects will be understood [1]. In the homogeneous subset of our language this can be entirely determined at compile time. The rules to check whether source code is type correct are ffl Early checks: verify for all calls x.p( that a procedure p is implemented by the declared type of x. ffl Equality checks: verify ....

Alan H. Borning and Daniel H. H. Ingalls. A type declaration and inference system for Smalltalk. In Ninth Symposium on Principles of Programming Languages, pages 133--141, 1982.

No context found.

Borning, A.H., Ingalls, D.H., A Type Declaration and Inference System for Smalltalk. In Proc. ACM Symp. Principles of Programming Languages, ACM Press, 1982, pp. 133--141.

No context found.

A. H. Borning and D. H. H. Ingalls, `A type declaration and inference system for Smalltalk', Conference Record of the Ninth Annual ACM Symposium on Principles of Programming Languages, 1982, pp. 133--139.

No context found.

A. H. Borning and D. H. Ingalls. "A type declaration and inference system for Smalltalk." In Proc. of the ACM Symp. on Principles of Programming Languages, 1982, pp. 133--141.

No context found.

Borning, A. H., Ingalls, D. H. H. A Type Declaration and Inference System for Smalltalk. In Ninth Symposium on Principles of Programming Languages, pages 133-141. ACM Press, January 1982.

No context found.

Borning, Alan H. and Ingalls, Daniel H. H. "A Type Declaration and Inference System for Smalltalk" ACM POPL 9, 1982, pp.133-141.

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A. H. Borning and D. H. H. Ingalls. A Type Declaration and Inference System for Smalltalk. In Conference Record of the Ninth Annual Symposium on Foundations of Computer Science, p. 133-139, 1982.

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