Lee, E. Object Storage and Inheritance for SELF, a Prototype-Based ObjectOriented Programming Language. Engineer's thesis, Stanford University (1988).  Home/Search   Document Not in Database   Summary   Related Articles   Check

....programs. However, they do not all offer exactly the same perspective; there are many different ideas about the nature of object oriented computation. In this paper, we present SELF, a programming language with a new perspective on objects and message passing. Like the Smalltalk 80 1 language [6], SELF is designed to support exploratory programming This work is partially supported by Xerox, and partially by National Science Foundation Presidential Young Investigator Grant #CCR 8657631, Sun Microsystems, the Powell Foundation, IBM, Apple Computer, DEC, NCR, Texas Instruments, and Cray ....

....slots, initialized to the right tree. prototypical (empty) tree. contents. Assignable slot for contents. 8 Related Work We would like to express our deep appreciation to the past and present members of the System Concepts Laboratory at Xerox PARC for blazing the trail with Smalltalk [6]. The way SELF accesses state via message passing owes much to conversations with Peter Deutsch, and is reminiscent of an earlier unpublished language of his called O. Some Smalltalk programmers have already adopted this style of variable accessing [11] Trellis Owl is an independently designed ....

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Lee, E. Object Storage and Inheritance for SELF, a Prototype-Based ObjectOriented Programming Language. Engineer's thesis, Stanford University (1988).

....of message passing and the lack of static type information to reduce either of these costs. This paper describes new techniques for extracting and preserving static type information in dynamicallytyped object oriented programs. This work continues our earlier work on the SELF programming language [12, 22]. SELF is a new dynamically typed object oriented language in the spirit of Smalltalk 80 1 [5] but is novel in its use of prototypes instead of classes and its use of messages instead of variables to access state. These features make SELF programs even harder to run efficiently than other ....

Lee, E. Object Storage and Inheritance for SELF, a Prototype-Based ObjectOriented Programming Language. Engineer's thesis, Stanford University (1988).

....LRU information to determine which compiled methods to flush. Finally, the virtual machine also contains numerous primitives that can be invoked by SELF programs to perform arithmetic, I O, graphics, and so on. New primitives can be dynamically linked into the system at runtime. References [88], 115] and [21] contain further details about the system. 2.2.2 Efficiency Since SELF s pure semantics threatened to make programs extremely inefficient, much of the early implementation effort went into compiler techniques for optimizing SELF programs. Some of these techniques were very ....

Elgin Lee. Object Storage and Inheritance for SELF, a Prototype-Based Object-Oriented Programming Language. Engineer's thesis, Stanford University, 1988.

....objects to inherit from (or delegate to) other objects. The issues surrounding inheritance and encapsulation need to be revisited when designing such a language. This paper describes the inheritance and encapsulation mechanisms we designed and implemented in one prototype based language, SELF [4, 5, 11, 25]. Our design This work has been generously supported by National Science Foundation Presidential Young Investigator Grant #CCR 8657631, and by Sun Microsystems, IBM, Apple Computer, Cray Laboratories, Tandem Computers, NCR, Texas Instruments, and DEC. Author s present address: Sun ....

....its slots are its arguments and local variables. An object may allow assignments to a data slot by associating an assignment slot with the data slot. New objects are created by cloning (shallow copying) pre existing objects. For a more complete description of SELF s syntax and object model, see [5, 11, 25]. In the absence of inheritance, message lookup in SELF is handled by searching the receiver for a slot that matches the message name and evaluating the contents of the matching slot (or generating a messageNotUnderstood error if there is no matching slot) Evaluating a method executes its ....

Lee, E. Object Storage and Inheritance for SELF, a Prototype-Based ObjectOriented Programming Language. Engineer's thesis, Stanford University (1988).

....references between objects. It creates new objects and reclaims the resources consumed by inaccessible objects. An ideal memory system would squeeze as many objects into as little memory as possible, for high performance at low cost. An earlier version of our SELF memory system was documented in [16]. Much of our memory system design exploits technology proven in existing highperformance Smalltalk systems. For minimal overhead in the common case, our SELF system represents object references using direct tagged pointers, rather than indirectly through an object table. Allocation and garbage ....

....to slots local to a method invocation ( local variable accesses) since these could never do anything other than access data. We computed the MiMS rating of our first generation SELF system for the Richards benchmark on the SPARC based Sun 4 260 to be 3. 3 MiMS, or a message executed every 300ns [16]. The efficiency of an object oriented system is inversely proportional to the number of instructions executed per message sent. The cycle time on the Sun 4 260 is 60ns [21] giving our SELF system a cost per message of about 5 cycles. Since the SPARC has been clocked at 1.6 cycles per instruction ....

Lee, E. Object Storage and Inheritance for SELF, a Prototype-Based ObjectOriented Programming Language. Engineer's thesis, Stanford University (1988).

....of the possibilities provided by class based systems, and finally, exploiting this additional flexibility need not lead to unstructured programs. The ideas presented here are based on the lessons we learned as we found ways to organize code in SELF, a dynamically typed prototype based language [3, 4, 10, 18]. Accordingly, we will illustrate the ideas using examples in SELF, but the ideas could be applied as well to other classless languages providing similar inheritance models. 2 Sharing Programming in an object oriented language largely revolves around specifying sharing relationships: what code is ....

Lee, E. Object Storage and Inheritance for SELF, a Prototype-Based ObjectOriented Programming Language. Engineer's thesis, Stanford University (1988).

....and a user interface tightly coupled to the language. SELF is a dynamically typed, prototype based, objectoriented language. This paper describes the approach we have taken with the design of the user interface for SELF. Detailed description of the language and implementation can be found in [1, 2, 6, 11]. Our prototype user interface for SELF provides browsing and inspecting of SELF objects by combining an object based model with an artificial reality. Emphasizing the problem domain objects rather than views of those objects discards a layer of indirection found in conventional window based user ....

Lee, E. Object Storage and Inheritance for SELF, a Prototype-Based ObjectOriented Programming Language. Engineer's thesis, Stanford University (1988).

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