Overloading and Subtyping
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1=Haskell =1=Making Our Own Types and Typeclasses
Haskell Making Our Own Types and Typeclasses http://igm.univ-mlv.fr/~vialette/?section=teaching St´ephaneVialette LIGM, Universit´eParis-Est Marne-la-Vall´ee November 13, 2016 Making Our Own Types and Typeclasses Algebraic data types intro So far, we've run into a lot of data types: Bool, Int, Char, Maybe, etc. But how do we make our own? One way is to use the data keyword to define a type. Let's see how the Bool type is defined in the standard library. data Bool= False| True data means that we're defining a new data type. Making Our Own Types and Typeclasses Algebraic data types intro data Bool= False| True The part before the = denotes the type, which is Bool. The parts after the = are value constructors. They specify the different values that this type can have. The | is read as or. So we can read this as: the Bool type can have a value of True or False. Both the type name and the value constructors have to be capital cased. Making Our Own Types and Typeclasses Algebraic data types intro We can think of the Int type as being defined like this: data Int=-2147483648|-2147483647| ...|-1|0|1|2| ...| 2147483647 The first and last value constructors are the minimum and maximum possible values of Int. It's not actually defined like this, the ellipses are here because we omitted a heapload of numbers, so this is just for illustrative purposes. Shape let's think about how we would represent a shape in Haskell. -
A Polymorphic Type System for Extensible Records and Variants
A Polymorphic Typ e System for Extensible Records and Variants Benedict R. Gaster and Mark P. Jones Technical rep ort NOTTCS-TR-96-3, November 1996 Department of Computer Science, University of Nottingham, University Park, Nottingham NG7 2RD, England. fbrg,[email protected] Abstract b oard, and another indicating a mouse click at a par- ticular p oint on the screen: Records and variants provide exible ways to construct Event = Char + Point : datatyp es, but the restrictions imp osed by practical typ e systems can prevent them from b eing used in ex- These de nitions are adequate, but they are not par- ible ways. These limitations are often the result of con- ticularly easy to work with in practice. For example, it cerns ab out eciency or typ e inference, or of the di- is easy to confuse datatyp e comp onents when they are culty in providing accurate typ es for key op erations. accessed by their p osition within a pro duct or sum, and This pap er describ es a new typ e system that reme- programs written in this way can b e hard to maintain. dies these problems: it supp orts extensible records and To avoid these problems, many programming lan- variants, with a full complement of p olymorphic op era- guages allow the comp onents of pro ducts, and the al- tions on each; and it o ers an e ective type inference al- ternatives of sums, to b e identi ed using names drawn gorithm and a simple compilation metho d. -
Java Secrets.Pdf
Java Secrets by Elliotte Rusty Harold IDG Books, IDG Books Worldwide, Inc. ISBN: 0764580078 Pub Date: 05/01/97 Buy It Preface About the Author Part I—How Java Works Chapter 1—Introducing Java SECRETS A Little Knowledge Can Be a Dangerous Thing What’s in This Book? Part I: How Java Works Part II: The sun Classes Part III: Platform-Dependent Java Why Java Secrets? Broader applicability More power Inspiration Where Did the Secrets Come From? Where is the documentation? The source code The API documentation What Versions of Java Are Covered? Some Objections Java is supposed to be platform independent Why aren’t these things documented? FUD (fear, uncertainty, and doubt) How secret is this, anyway? Summary Chapter 2—Primitive Data Types Bytes in Memory Variables, Values, and Identifiers Place-Value Number Systems Binary notation Hexadecimal notation Octal notation Integers ints Long, short, and byte Floating-Point Numbers Representing floating-point numbers in binary code Special values Denormalized floating-point numbers CHAR ASCII ISO Latin-1 Unicode UTF8 Boolean Cross-Platform Issues Byte order Unsigned integers Integer widths Conversions and Casting Using a cast The mechanics of conversion Bit-Level Operators Some terminology Bitwise operators Bit shift operators Summary Chapter 2—Primitive Data Types Bytes in Memory Variables, Values, and Identifiers Place-Value Number Systems Binary notation Hexadecimal notation Octal notation Integers ints Long, short, and byte Floating-Point Numbers Representing floating-point numbers in binary code -
Behavioral Subtyping, Specification Inheritance, and Modular Reasoning Gary T
Computer Science Technical Reports Computer Science 9-3-2006 Behavioral Subtyping, Specification Inheritance, and Modular Reasoning Gary T. Leavens Iowa State University David A. Naumann Iowa State University Follow this and additional works at: http://lib.dr.iastate.edu/cs_techreports Part of the Software Engineering Commons Recommended Citation Leavens, Gary T. and Naumann, David A., "Behavioral Subtyping, Specification Inheritance, and Modular Reasoning" (2006). Computer Science Technical Reports. 269. http://lib.dr.iastate.edu/cs_techreports/269 This Article is brought to you for free and open access by the Computer Science at Iowa State University Digital Repository. It has been accepted for inclusion in Computer Science Technical Reports by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Behavioral Subtyping, Specification Inheritance, and Modular Reasoning Abstract Behavioral subtyping is an established idea that enables modular reasoning about behavioral properties of object-oriented programs. It requires that syntactic subtypes are behavioral refinements. It validates reasoning about a dynamically-dispatched method call, say E.m(), using the specification associated with the static type of the receiver expression E. For languages with references and mutable objects the idea of behavioral subtyping has not been rigorously formalized as such, the standard informal notion has inadequacies, and exact definitions are not obvious. This paper formalizes behavioral subtyping and supertype abstraction for a Java-like sequential language with classes, interfaces, exceptions, mutable heap objects, references, and recursive types. Behavioral subtyping is proved sound and semantically complete for reasoning with supertype abstraction. Specification inheritance, as used in the specification language JML, is formalized and proved to entail behavioral subtyping. -
Lecture Slides
Outline Meta-Classes Guy Wiener Introduction AOP Classes Generation 1 Introduction Meta-Classes in Python Logging 2 Meta-Classes in Python Delegation Meta-Classes vs. Traditional OOP 3 Meta-Classes vs. Traditional OOP Outline Meta-Classes Guy Wiener Introduction AOP Classes Generation 1 Introduction Meta-Classes in Python Logging 2 Meta-Classes in Python Delegation Meta-Classes vs. Traditional OOP 3 Meta-Classes vs. Traditional OOP What is Meta-Programming? Meta-Classes Definition Guy Wiener Meta-Program A program that: Introduction AOP Classes One of its inputs is a program Generation (possibly itself) Meta-Classes in Python Its output is a program Logging Delegation Meta-Classes vs. Traditional OOP Meta-Programs Nowadays Meta-Classes Guy Wiener Introduction AOP Classes Generation Compilers Meta-Classes in Python Code Generators Logging Delegation Model-Driven Development Meta-Classes vs. Traditional Templates OOP Syntactic macros (Lisp-like) Meta-Classes The Problem With Static Programming Meta-Classes Guy Wiener Introduction AOP Classes Generation Meta-Classes How to share features between classes and class hierarchies? in Python Logging Share static attributes Delegation Meta-Classes Force classes to adhere to the same protocol vs. Traditional OOP Share code between similar methods Meta-Classes Meta-Classes Guy Wiener Introduction AOP Classes Definition Generation Meta-Classes in Python Meta-Class A class that creates classes Logging Delegation Objects that are instances of the same class Meta-Classes share the same behavior vs. Traditional OOP Classes that are instances of the same meta-class share the same behavior Meta-Classes Meta-Classes Guy Wiener Introduction AOP Classes Definition Generation Meta-Classes in Python Meta-Class A class that creates classes Logging Delegation Objects that are instances of the same class Meta-Classes share the same behavior vs. -
Haskell-Style Type Classes with Isabelle/Isar
Isar ∀ Isabelle= α λ β → Haskell-style type classes with Isabelle/Isar Florian Haftmann 20 February 2021 Abstract This tutorial introduces Isar type classes, which are a convenient mech- anism for organizing specifications. Essentially, they combine an op- erational aspect (in the manner of Haskell) with a logical aspect, both managed uniformly. 1 INTRODUCTION 1 1 Introduction Type classes were introduced by Wadler and Blott [8] into the Haskell lan- guage to allow for a reasonable implementation of overloading1. As a canon- ical example, a polymorphic equality function eq :: α ) α ) bool which is overloaded on different types for α, which is achieved by splitting introduc- tion of the eq function from its overloaded definitions by means of class and instance declarations: 2 class eq where eq :: α ) α ) bool instance nat :: eq where eq 0 0 = True eq 0 - = False eq - 0 = False eq (Suc n)(Suc m) = eq n m instance (α::eq; β::eq) pair :: eq where eq (x1; y1) (x2; y2) = eq x1 x2 ^ eq y1 y2 class ord extends eq where less-eq :: α ) α ) bool less :: α ) α ) bool Type variables are annotated with (finitely many) classes; these annotations are assertions that a particular polymorphic type provides definitions for overloaded functions. Indeed, type classes not only allow for simple overloading but form a generic calculus, an instance of order-sorted algebra [5, 6, 10]. From a software engineering point of view, type classes roughly correspond to interfaces in object-oriented languages like Java; so, it is naturally desirable that type classes do not only provide functions (class parameters) but also state specifications implementations must obey. -
OMG Meta Object Facility (MOF) Core Specification
Date : October 2019 OMG Meta Object Facility (MOF) Core Specification Version 2.5.1 OMG Document Number: formal/2019-10-01 Standard document URL: https://www.omg.org/spec/MOF/2.5.1 Normative Machine-Readable Files: https://www.omg.org/spec/MOF/20131001/MOF.xmi Informative Machine-Readable Files: https://www.omg.org/spec/MOF/20131001/CMOFConstraints.ocl https://www.omg.org/spec/MOF/20131001/EMOFConstraints.ocl Copyright © 2003, Adaptive Copyright © 2003, Ceira Technologies, Inc. Copyright © 2003, Compuware Corporation Copyright © 2003, Data Access Technologies, Inc. Copyright © 2003, DSTC Copyright © 2003, Gentleware Copyright © 2003, Hewlett-Packard Copyright © 2003, International Business Machines Copyright © 2003, IONA Copyright © 2003, MetaMatrix Copyright © 2015, Object Management Group Copyright © 2003, Softeam Copyright © 2003, SUN Copyright © 2003, Telelogic AB Copyright © 2003, Unisys USE OF SPECIFICATION - TERMS, CONDITIONS & NOTICES The material in this document details an Object Management Group specification in accordance with the terms, conditions and notices set forth below. This document does not represent a commitment to implement any portion of this specification in any company's products. The information contained in this document is subject to change without notice. LICENSES The companies listed above have granted to the Object Management Group, Inc. (OMG) a nonexclusive, royalty-free, paid up, worldwide license to copy and distribute this document and to modify this document and distribute copies of the modified version. Each of the copyright holders listed above has agreed that no person shall be deemed to have infringed the copyright in the included material of any such copyright holder by reason of having used the specification set forth herein or having conformed any computer software to the specification. -
Advances in Programming Languages Lecture 18: Concurrency and More in Rust
Advances in Programming Languages Lecture 18: Concurrency and More in Rust Ian Stark School of Informatics The University of Edinburgh Friday 24 November 2016 Semester 1 Week 10 https://blog.inf.ed.ac.uk/apl16 Topic: Programming for Memory Safety The final block of lectures cover features used in the Rust programming language. Introduction: Zero-Cost Abstractions (and their cost) Control of Memory: Ownership Concurrency and more This section of the course is entirely new — Rust itself is not that old — and I apologise for any consequent lack of polish. Ian Stark Advances in Programming Languages / Lecture 18: Concurrency and More in Rust 2016-11-24 The Rust Programming Language The Rust language is intended as a tool for safe systems programming. Three key objectives contribute to this. Zero-cost abstractions Basic References Memory safety https://www.rust-lang.org https://blog.rust-lang.org Safe concurrency The “systems programming” motivation resonates with that for imperative C/C++. The “safe” part draws extensively on techniques developed for functional Haskell and OCaml. Sometimes these align more closely than you might expect, often by overlap between two aims: Precise control for the programmer; Precise information for the compiler. Ian Stark Advances in Programming Languages / Lecture 18: Concurrency and More in Rust 2016-11-24 Previous Homework Watch This Peter O’Hearn: Reasoning with Big Code https://is.gd/reasoning_big_code Talk at the Alan Turing Institute about how Facebook is using automatic verification at scale to check code and give feedback to programmers. Ian Stark Advances in Programming Languages / Lecture 18: Concurrency and More in Rust 2016-11-24 Guest Speaker ! Probabilistic Programming: What is it and how do we make it better? Maria Gorinova University of Edinburgh 3.10pm Tuesday 29 November 2016 Ian Stark Advances in Programming Languages / Lecture 18: Concurrency and More in Rust 2016-11-24 Optional: Review and Exam Preparation ! The final lecture will be an exam review, principally for single-semester visiting students. -
Metaclasses 4 ◆ Dynamic Binding Implies That Classes Must Have Some ◆ Meta-: Beyond; Transcending; More Comprehensive; E.G., As Memory Representation
® 1 ® Class Representation in Memory? 2 Case Study: Meta Classes ◆ A class is an abstract entity, so why should it be represented in the runtime environment? ◆ Answer: Dynamic Binding! ◆ Class representation in memory ● The actual method bound to a message is determined at run time based on the type (class) of an object. ◆ Class variables and class methods ● There must be a link between the object and its ◆ Meta Classes methods. ● Since these links are the same for all objects of the ◆ 3 Level System same class, it makes sense to share the representation. ◆ ◆ 4 Level System Schematic diagram, common to all OO languages: Method ◆ 5 Level System 1 Method ◆ 1 Level System Class Rep 2 ◆ Msg Object Methods Infinite Levels System Table Methodn oop Õ Ö oop Õ Ö ® A Class as an Object? 3 ® Metaclasses 4 ◆ Dynamic binding implies that classes must have some ◆ Meta-: Beyond; transcending; more comprehensive; e.g., as memory representation. in metalinguistics. ◆ Why not as an object? ◆ Class: generates instances. ◆ Answer: Let's go for it! ◆ Metaclass: a class whose instances are classes. ● Each object o has a pointer to its class object c which is the ◆ Terminal Instance: cannot be instantiated further. object representing the class to which o belongs. Objects Class Classes Terminal Instances Novel Play Instantiable objects Non instantiable objects Macbeth Othello Metaclasses Instances are classes 1984 War & Peace As you like Main Text Book Reference: G.Masini et al. Oliver Twist Object-Oriented Languages, APIC series, No.34 oop Õ Ö oop Õ Ö ® 5 ® 6 Taxonomy of Metaclass Systems The 3 Level System ◆ 1-Level System: Objects only Object ● Each object describes itself INSTANCE _OF ● No need for classes: objects are ìinstantiatedî or ìinheritedî from SUBCLASS _OF other objects Class Example: Self VARIABLES instance_of ,167$1&(B2) ◆ 2-Level System: Objects, Classes METHODS .. -
Developing Rust on Bare-Metal
RustyGecko - Developing Rust on Bare-Metal An experimental embedded software platform Håvard Wormdal Høiby Sondre Lefsaker Master of Science in Computer Science Submission date: June 2015 Supervisor: Magnus Lie Hetland, IDI Co-supervisor: Antonio Garcia Guirado, IDI Marius Grannæs, Silicon Labs Norwegian University of Science and Technology Department of Computer and Information Science Preface This report is submitted to the Norwegian University of Science and Technology in fulfillment of the requirements for master thesis. This work has been performed at the Department of Computer and Information Science, NTNU, with Prof. Magnus Lie Hetland as the supervisor, Antonio Garcia Guirado (ARM), and Marius Grannæs (Silicon Labs) as co-supervisors. The initial problem description was our own proposal and further developed in co-operation with our supervisors. Acknowledgements Thanks to Magnus Lie Hetland, Antonio Garcia Guirado, and Marius Grannæs for directions and guidance on technical issues and this report. Thanks to Silicon Labs for providing us with development platforms for us to develop and test our implementation on. Thanks to Antonio Garcia Guirado for the implementation of the CircleGame application for us to port to Rust and use in our benchmarks. Thanks to Itera w/Tommy Ryen for office space. A special thanks to Leslie Ho and Siri Aagedal for all the support and for proofreading the thesis. Sondre Lefsaker and H˚avard Wormdal Høiby 2015-06-14 i Project Description The Rust programming language is a new system language developed by Mozilla. With the language being statically compiled and built on the LLVM compiler infras- tructure, and because of features like low-level control and zero-cost abstractions, the language is a candidate for use in bare-metal systems. -
Xtend User Guide
Xtend User Guide September 10, 2013 Contents I. Getting Started 5 1. Introduction 6 2. Hello World 7 3. The Movies Example 9 3.1. The Data . .9 3.2. Parsing The Data . 10 3.3. Answering Some Questions . 11 3.3.1. Question 1 : What Is The Number Of Action Movies? . 11 3.3.2. Question 2 : What Is The Year The Best Movie From The 80's Was Released? . 12 3.3.3. Question 3 : What Is The The Sum Of All Votes Of The Top Two Movies?................................. 13 II. Reference Documentation 14 4. Java Interoperability 15 4.1. Type Inference . 15 4.2. Conversion Rules . 15 4.3. Interoperability with Java . 16 5. Classes and Members 17 5.1. Package Declaration . 17 5.2. Imports . 17 5.3. Class Declaration . 18 5.4. Constructors . 19 5.5. Fields . 19 5.6. Methods . 20 5.6.1. Abstract Methods . 20 5.6.2. Overriding Methods . 21 5.6.3. Declared Exceptions . 21 5.6.4. Inferred Return Types . 21 5.6.5. Generic Methods . 22 2 5.6.6. Dispatch Methods . 22 5.7. Annotations . 26 5.8. Extension Methods . 26 5.8.1. Extensions from the Library . 27 5.8.2. Local Extension Methods . 28 5.8.3. Extension Imports . 28 5.8.4. Extension Provider . 29 5.9. Interface Declaration . 29 5.10. Annotation Type Declaration . 30 5.11. Enum Type Declaration . 30 6. Expressions 31 6.1. Literals . 31 6.1.1. String Literals . 31 6.1.2. Character Literals . 32 6.1.3. Number Literals . -
The Rust Programming Language
The Rust Programming Language The Rust Team 2016-10-01 2 Contents 1 Introduction 11 Contributing ...................................... 11 2 Getting Started 13 Installing Rust ..................................... 13 Hello, world! ...................................... 16 Hello, Cargo! ...................................... 19 Closing Thoughts .................................... 23 3 Tutorial: Guessing Game 25 Set up .......................................... 25 Processing a Guess ................................... 26 Generating a secret number .............................. 30 Comparing guesses ................................... 33 Looping ......................................... 37 Complete! ........................................ 41 4 Syntax and Semantics 43 Variable Bindings ....................................... 43 Patterns ......................................... 43 Type annotations .................................... 44 Mutability ........................................ 44 Initializing bindings .................................. 45 Scope and shadowing .................................. 46 Functions ........................................... 48 Primitive Types ........................................ 53 Booleans ......................................... 53 4 CONTENTS char ........................................... 53 Numeric types ..................................... 54 Arrays .......................................... 55 Slices ........................................... 56 str ...........................................