Exploring Languages with Interpreters and Functional Programming Chapter 21
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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. -
Create Union Variables Difference Between Unions and Structures
Union is a user-defined data type similar to a structure in C programming. How to define a union? We use union keyword to define unions. Here's an example: union car { char name[50]; int price; }; The above code defines a user define data type union car. Create union variables When a union is defined, it creates a user-define type. However, no memory is allocated. To allocate memory for a given union type and work with it, we need to create variables. Here's how we create union variables: union car { char name[50]; int price; } car1, car2, *car3; In both cases, union variables car1, car2, and a union pointer car3 of union car type are created. How to access members of a union? We use . to access normal variables of a union. To access pointer variables, we use ->operator. In the above example, price for car1 can be accessed using car1.price price for car3 can be accessed using car3->price Difference between unions and structures Let's take an example to demonstrate the difference between unions and structures: #include <stdio.h> union unionJob { //defining a union char name[32]; float salary; int workerNo; } uJob; struct structJob { char name[32]; float salary; int workerNo; } sJob; main() { printf("size of union = %d bytes", sizeof(uJob)); printf("\nsize of structure = %d bytes", sizeof(sJob)); } Output size of union = 32 size of structure = 40 Why this difference in size of union and structure variables? The size of structure variable is 40 bytes. It's because: size of name[32] is 32 bytes size of salary is 4 bytes size of workerNo is 4 bytes However, the size of union variable is 32 bytes. -
A Hybrid Static Type Inference Framework with Neural
HiTyper: A Hybrid Static Type Inference Framework with Neural Prediction Yun Peng Zongjie Li Cuiyun Gao∗ The Chinese University of Hong Kong Harbin Institute of Technology Harbin Institute of Technology Hong Kong, China Shenzhen, China Shenzhen, China [email protected] [email protected] [email protected] Bowei Gao David Lo Michael Lyu Harbin Institute of Technology Singapore Management University The Chinese University of Hong Kong Shenzhen, China Singapore Hong Kong, China [email protected] [email protected] [email protected] ABSTRACT also supports type annotations in the Python Enhancement Pro- Type inference for dynamic programming languages is an impor- posals (PEP) [21, 22, 39, 43]. tant yet challenging task. By leveraging the natural language in- Type prediction is a popular task performed by most attempts. formation of existing human annotations, deep neural networks Traditional static type inference techniques [4, 9, 14, 17, 36] and outperform other traditional techniques and become the state-of- type inference tools such as Pytype [34], Pysonar2 [33], and Pyre the-art (SOTA) in this task. However, they are facing some new Infer [31] can predict sound results for the variables with enough challenges, such as fixed type set, type drift, type correctness, and static constraints, e.g., a = 1, but are unable to handle the vari- composite type prediction. ables with few static constraints, e.g. most function arguments. To mitigate the challenges, in this paper, we propose a hybrid On the other hand, dynamic type inference techniques [3, 37] and type inference framework named HiTyper, which integrates static type checkers simulate the workflow of functions and solve types inference into deep learning (DL) models for more accurate type according to input cases and typing rules. -
[Note] C/C++ Compiler Package for RX Family (No.55-58)
RENESAS TOOL NEWS [Note] R20TS0649EJ0100 Rev.1.00 C/C++ Compiler Package for RX Family (No.55-58) Jan. 16, 2021 Overview When using the CC-RX Compiler package, note the following points. 1. Using rmpab, rmpaw, rmpal or memchr intrinsic functions (No.55) 2. Performing the tail call optimization (No.56) 3. Using the -ip_optimize option (No.57) 4. Using multi-dimensional array (No.58) Note: The number following the note is an identification number for the note. 1. Using rmpab, rmpaw, rmpal or memchr intrinsic functions (No.55) 1.1 Applicable products CC-RX V2.00.00 to V3.02.00 1.2 Details The execution result of a program including the intrinsic function rmpab, rmpaw, rmpal, or the standard library function memchr may not be as intended. 1.3 Conditions This problem may arise if all of the conditions from (1) to (3) are met. (1) One of the following calls is made: (1-1) rmpab or __rmpab is called. (1-2) rmpaw or __rmpaw is called. (1-3) rmpal or __rmpal is called. (1-4) memchr is called. (2) One of (1-1) to (1-3) is met, and neither -optimize=0 nor -noschedule option is specified. (1-4) is met, and both -size and -avoid_cross_boundary_prefetch (Note 1) options are specified. (3) Memory area that overlaps with the memory area (Note2) read by processing (1) is written in a single function. (This includes a case where called function processing is moved into the caller function by inline expansion.) Note 1: This is an option added in V2.07.00. -
ACDT: Architected Composite Data Types Trading-In Unfettered Data Access for Improved Execution
ACDT: Architected Composite Data Types Trading-in Unfettered Data Access for Improved Execution Andres Marquez∗, Joseph Manzano∗, Shuaiwen Leon Song∗, Benoˆıt Meistery Sunil Shresthaz, Thomas St. Johnz and Guang Gaoz ∗Pacific Northwest National Laboratory fandres.marquez,joseph.manzano,[email protected] yReservoir Labs [email protected] zUniversity of Delaware fshrestha,stjohn,[email protected] Abstract— reduction approaches associated with improved data locality, obtained through optimized data and computation distribution. With Exascale performance and its challenges in mind, one ubiquitous concern among architects is energy efficiency. In the SW-stack we foresee the runtime system to have a Petascale systems projected to Exascale systems are unsustainable particular important role to contribute to the solution of the at current power consumption rates. One major contributor power challenge. It is here where the massive concurrency is to system-wide power consumption is the number of memory managed and where judicious data layouts [11] and data move- operations leading to data movement and management techniques ments are orchestrated. With that in mind, we set to investigate applied by the runtime system. To address this problem, we on how to improve efficiency of a massively multithreaded present the concept of the Architected Composite Data Types adaptive runtime system in managing and moving data, and the (ACDT) framework. The framework is made aware of data trade-offs an improved data management efficiency requires. composites, assigning them a specific layout, transformations Specifically, in the context of run-time system (RTS), we and operators. Data manipulation overhead is amortized over a explore the power efficiency potential that data compression larger number of elements and program performance and power efficiency can be significantly improved. -
Programming the Capabilities of the PC Have Changed Greatly Since the Introduction of Electronic Computers
1 www.onlineeducation.bharatsevaksamaj.net www.bssskillmission.in INTRODUCTION TO PROGRAMMING LANGUAGE Topic Objective: At the end of this topic the student will be able to understand: History of Computer Programming C++ Definition/Overview: Overview: A personal computer (PC) is any general-purpose computer whose original sales price, size, and capabilities make it useful for individuals, and which is intended to be operated directly by an end user, with no intervening computer operator. Today a PC may be a desktop computer, a laptop computer or a tablet computer. The most common operating systems are Microsoft Windows, Mac OS X and Linux, while the most common microprocessors are x86-compatible CPUs, ARM architecture CPUs and PowerPC CPUs. Software applications for personal computers include word processing, spreadsheets, databases, games, and myriad of personal productivity and special-purpose software. Modern personal computers often have high-speed or dial-up connections to the Internet, allowing access to the World Wide Web and a wide range of other resources. Key Points: 1. History of ComputeWWW.BSSVE.INr Programming The capabilities of the PC have changed greatly since the introduction of electronic computers. By the early 1970s, people in academic or research institutions had the opportunity for single-person use of a computer system in interactive mode for extended durations, although these systems would still have been too expensive to be owned by a single person. The introduction of the microprocessor, a single chip with all the circuitry that formerly occupied large cabinets, led to the proliferation of personal computers after about 1975. Early personal computers - generally called microcomputers - were sold often in Electronic kit form and in limited volumes, and were of interest mostly to hobbyists and technicians. -
Coredx DDS Type System
CoreDX DDS Type System Designing and Using Data Types with X-Types and IDL 4 2017-01-23 Table of Contents 1Introduction........................................................................................................................1 1.1Overview....................................................................................................................2 2Type Definition..................................................................................................................2 2.1Primitive Types..........................................................................................................3 2.2Collection Types.........................................................................................................4 2.2.1Enumeration Types.............................................................................................4 2.2.1.1C Language Mapping.................................................................................5 2.2.1.2C++ Language Mapping.............................................................................6 2.2.1.3C# Language Mapping...............................................................................6 2.2.1.4Java Language Mapping.............................................................................6 2.2.2BitMask Types....................................................................................................7 2.2.2.1C Language Mapping.................................................................................8 2.2.2.2C++ Language Mapping.............................................................................8 -
Certification of a Tool Chain for Deductive Program Verification Paolo Herms
Certification of a Tool Chain for Deductive Program Verification Paolo Herms To cite this version: Paolo Herms. Certification of a Tool Chain for Deductive Program Verification. Other [cs.OH]. Université Paris Sud - Paris XI, 2013. English. NNT : 2013PA112006. tel-00789543 HAL Id: tel-00789543 https://tel.archives-ouvertes.fr/tel-00789543 Submitted on 18 Feb 2013 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. UNIVERSITÉ DE PARIS-SUD École doctorale d’Informatique THÈSE présentée pour obtenir le Grade de Docteur en Sciences de l’Université Paris-Sud Discipline : Informatique PAR Paolo HERMS −! − SUJET : Certification of a Tool Chain for Deductive Program Verification soutenue le 14 janvier 2013 devant la commission d’examen MM. Roberto Di Cosmo Président du Jury Xavier Leroy Rapporteur Gilles Barthe Rapporteur Emmanuel Ledinot Examinateur Burkhart Wolff Examinateur Claude Marché Directeur de Thèse Benjamin Monate Co-directeur de Thèse Jean-François Monin Invité Résumé Cette thèse s’inscrit dans le domaine de la vérification du logiciel. Le but de la vérification du logiciel est d’assurer qu’une implémentation, un programme, répond aux exigences, satis- fait sa spécification. Cela est particulièrement important pour le logiciel critique, tel que des systèmes de contrôle d’avions, trains ou centrales électriques, où un mauvais fonctionnement pendant l’opération aurait des conséquences catastrophiques. -
Chapter 5 Type Declarations
Ch.5: Type Declarations Plan Chapter 5 Type Declarations (Version of 27 September 2004) 1. Renaming existing types . 5.2 2. Enumeration types . 5.3 3. Constructed types . 5.5 4. Parameterised/polymorphic types . 5.10 5. Exceptions, revisited . 5.12 6. Application: expression evaluation . 5.13 °c P. Flener/IT Dept/Uppsala Univ. FP 5.1 Ch.5: Type Declarations 5.1. Renaming existing types 5.1. Renaming existing types Example: polynomials, revisited Representation of a polynomial by a list of integers: type poly = int list ² Introduction of an abbreviation for the type int list ² The two names denote the same type ² The object [4,2,8] is of type poly and of type int list - type poly = int list ; type poly = int list - type poly2 = int list ; type poly2 = int list - val p:poly = [1,2] ; val p = [1,2] : poly - val p2:poly2 = [1,2] ; val p2 = [1,2] : poly2 - p = p2 ; val it = true : bool °c P. Flener/IT Dept/Uppsala Univ. FP 5.2 Ch.5: Type Declarations 5.2. Enumeration types 5.2. Enumeration types Declaration of a new type having a finite number of values Example (weekend.sml) datatype months = Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec datatype days = Mon | Tue | Wed | Thu | Fri | Sat | Sun fun weekend Sat = true | weekend Sun = true | weekend d = false - datatype months = Jan | ... | Dec ; datatype months = Jan | ... | Dec - datatype days = Mon | ... | Sun ; datatype days = Mon | ... | Sun - fun weekend ... ; val weekend = fn : days -> bool °c P. Flener/IT Dept/Uppsala Univ. FP 5.3 Ch.5: Type Declarations 5.2. -
Nominal Wyvern: Employing Semantic Separation for Usability Yu Xiang Zhu CMU-CS-19-105 April 2019
Nominal Wyvern: Employing Semantic Separation for Usability Yu Xiang Zhu CMU-CS-19-105 April 2019 School of Computer Science Carnegie Mellon University Pittsburgh, PA 15213 Thesis Committee: Jonathan Aldrich, Chair Heather Miller Alex Potanin, Victoria University of Wellington, NZ Submitted in partial fulfillment of the requirements for the degree of Master of Science. Copyright c 2019 Yu Xiang Zhu Keywords: Nominality, Wyvern, Dependent Object Types, Subtype Decidability Abstract This thesis presents Nominal Wyvern, a nominal type system that empha- sizes semantic separation for better usability. Nominal Wyvern is based on the dependent object types (DOT) calculus, which provides greater expressiv- ity than traditional object-oriented languages by incorporating concepts from functional languages. Although DOT is generally perceived to be nominal due to its path-dependent types, it is still a mostly structural system and relies on the free construction of types. This can present usability issues in a subtyping- based system where the semantics of a type are as important as its syntactic structure. Nominal Wyvern overcomes this problem by semantically separat- ing structural type/subtype definitions from ad hoc type refinements and type bound declarations. In doing so, Nominal Wyvern is also able to overcome the subtype undecidability problem of DOT by adopting a semantics-based sep- aration between types responsible for recursive subtype definitions and types that represent concrete data. The result is a more intuitive type system that achieves nominality and decidability while maintaining the expressiveness of F-bounded polymorphism that is used in practice. iv Acknowledgments This research would not have been possible without the support from the following in- dividuals. -
Julia's Efficient Algorithm for Subtyping Unions and Covariant
Julia’s Efficient Algorithm for Subtyping Unions and Covariant Tuples Benjamin Chung Northeastern University, Boston, MA, USA [email protected] Francesco Zappa Nardelli Inria of Paris, Paris, France [email protected] Jan Vitek Northeastern University, Boston, MA, USA Czech Technical University in Prague, Czech Republic [email protected] Abstract The Julia programming language supports multiple dispatch and provides a rich type annotation language to specify method applicability. When multiple methods are applicable for a given call, Julia relies on subtyping between method signatures to pick the correct method to invoke. Julia’s subtyping algorithm is surprisingly complex, and determining whether it is correct remains an open question. In this paper, we focus on one piece of this problem: the interaction between union types and covariant tuples. Previous work normalized unions inside tuples to disjunctive normal form. However, this strategy has two drawbacks: complex type signatures induce space explosion, and interference between normalization and other features of Julia’s type system. In this paper, we describe the algorithm that Julia uses to compute subtyping between tuples and unions – an algorithm that is immune to space explosion and plays well with other features of the language. We prove this algorithm correct and complete against a semantic-subtyping denotational model in Coq. 2012 ACM Subject Classification Theory of computation → Type theory Keywords and phrases Type systems, Subtyping, Union types Digital Object Identifier 10.4230/LIPIcs.ECOOP.2019.24 Category Pearl Supplement Material ECOOP 2019 Artifact Evaluation approved artifact available at https://dx.doi.org/10.4230/DARTS.5.2.8 Acknowledgements The authors thank Jiahao Chen for starting us down the path of understanding Julia, and Jeff Bezanson for coming up with Julia’s subtyping algorithm.