The Grace Programming Language Draft Specification Version 0.5. 2025" (2015)
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First Class Overloading Via Insersection Type Parameters⋆
First Class Overloading via Insersection Type Parameters? Elton Cardoso2, Carlos Camar~ao1, and Lucilia Figueiredo2 1 Universidade Federal de Minas Gerais, [email protected] 2 Universidade Federal de Ouro Preto [email protected], [email protected] Abstract The Hindley-Milner type system imposes the restriction that function parameters must have monomorphic types. Lifting this restric- tion and providing system F “first class" polymorphism is clearly desir- able, but comes with the difficulty that inference of types for system F is undecidable. More practical type systems incorporating types of higher- rank have recently been proposed, that rely on system F but require type annotations for the definition of functions with polymorphic type parameters. However, these type annotations inevitably disallow some possible uses of higher-rank functions. To avoid this problem and to pro- mote code reuse, we explore using intersection types for specifying the types of function parameters that are used polymorphically inside the function body, allowing a flexible use of such functions, on applications to both polymorphic or overloaded arguments. 1 Introduction The Hindley-Milner type system [9] (HM) has been successfuly used as the basis for type systems of modern functional programming languages, such as Haskell [23] and ML [20]. This is due to its remarkable properties that a compiler can in- fer the principal type for any language expression, without any help from the programmer, and the type inference algorithm [5] is relatively simple. This is achieved, however, by imposing some restrictions, a major one being that func- tion parameters must have monomorphic types. For example, the following definition is not allowed in the HM type system: foo g = (g [True,False], g ['a','b','c']) Since parameter g is used with distinct types in the function's body (being applied to both a list of booleans and a list of characters), its type cannot be monomorphic, and this definition of foo cannot thus be typed in HM. -
Program #6: Word Count
CSc 227 — Program Design and Development Spring 2014 (McCann) http://www.cs.arizona.edu/classes/cs227/spring14/ Program #6: Word Count Due Date: March 11 th, 2014, at 9:00 p.m. MST Overview: The UNIX operating system (and its variants, of which Linux is one) includes quite a few useful utility programs. One of those is wc, which is short for Word Count. The purpose of wc is to give users an easy way to determine the size of a text file in terms of the number of lines, words, and bytes it contains. (It can do a bit more, but that’s all of the functionality that we are concerned with for this assignment.) Counting lines is done by looking for “end of line” characters (\n (ASCII 10) for UNIX text files, or the pair \r\n (ASCII 13 and 10) for Windows/DOS text files). Counting words is also straight–forward: Any sequence of characters not interrupted by “whitespace” (spaces, tabs, end–of–line characters) is a word. Of course, whitespace characters are characters, and need to be counted as such. A problem with wc is that it generates a very minimal output format. Here’s an example of what wc produces on a Linux system when asked to count the content of a pair of files; we can do better! $ wc prog6a.dat prog6b.dat 2 6 38 prog6a.dat 32 321 1883 prog6b.dat 34 327 1921 total Assignment: Write a Java program (completely documented according to the class documentation guidelines, of course) that counts lines, words, and bytes (characters) of text files. -
Disjoint Polymorphism
Disjoint Polymorphism João Alpuim, Bruno C. d. S. Oliveira, and Zhiyuan Shi The University of Hong Kong {alpuim,bruno,zyshi}@cs.hku.hk Abstract. The combination of intersection types, a merge operator and parametric polymorphism enables important applications for program- ming. However, such combination makes it hard to achieve the desirable property of a coherent semantics: all valid reductions for the same expres- sion should have the same value. Recent work proposed disjoint inter- sections types as a means to ensure coherence in a simply typed setting. However, the addition of parametric polymorphism was not studied. This paper presents Fi: a calculus with disjoint intersection types, a vari- ant of parametric polymorphism and a merge operator. Fi is both type- safe and coherent. The key difficulty in adding polymorphism is that, when a type variable occurs in an intersection type, it is not statically known whether the instantiated type will be disjoint to other compo- nents of the intersection. To address this problem we propose disjoint polymorphism: a constrained form of parametric polymorphism, which allows disjointness constraints for type variables. With disjoint polymor- phism the calculus remains very flexible in terms of programs that can be written, while retaining coherence. 1 Introduction Intersection types [20,43] are a popular language feature for modern languages, such as Microsoft’s TypeScript [4], Redhat’s Ceylon [1], Facebook’s Flow [3] and Scala [37]. In those languages a typical use of intersection types, which has been known for a long time [19], is to model the subtyping aspects of OO-style multiple inheritance. -
DC Console Using DC Console Application Design Software
DC Console Using DC Console Application Design Software DC Console is easy-to-use, application design software developed specifically to work in conjunction with AML’s DC Suite. Create. Distribute. Collect. Every LDX10 handheld computer comes with DC Suite, which includes seven (7) pre-developed applications for common data collection tasks. Now LDX10 users can use DC Console to modify these applications, or create their own from scratch. AML 800.648.4452 Made in USA www.amltd.com Introduction This document briefly covers how to use DC Console and the features and settings. Be sure to read this document in its entirety before attempting to use AML’s DC Console with a DC Suite compatible device. What is the difference between an “App” and a “Suite”? “Apps” are single applications running on the device used to collect and store data. In most cases, multiple apps would be utilized to handle various operations. For example, the ‘Item_Quantity’ app is one of the most widely used apps and the most direct means to take a basic inventory count, it produces a data file showing what items are in stock, the relative quantities, and requires minimal input from the mobile worker(s). Other operations will require additional input, for example, if you also need to know the specific location for each item in inventory, the ‘Item_Lot_Quantity’ app would be a better fit. Apps can be used in a variety of ways and provide the LDX10 the flexibility to handle virtually any data collection operation. “Suite” files are simply collections of individual apps. Suite files allow you to easily manage and edit multiple apps from within a single ‘store-house’ file and provide an effortless means for device deployment. -
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. -
[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. -
Dot at Command Firmware Release 4.0.0 Release 3.3.5
Product Change Notification Software Release Notes Dot AT Command Firmware Release 4.0.0 Release 3.3.5 MultiTech xDot® MultiTech mDot™ Date: March 30, 2021 Contents Product Change Notification (PCN) Number PCN 03302021-001 (Dot) I. Overview II. Suggested Action Plan I. Overview MultiTech announces the availability of new AT Command III. Release 4.0.0 Overview Firmware for use on MultiTech® Long Range LoRa® Modules: MultiTech xDot® (MTXDOT Series) IV. Release 3.3.5 Overview MultiTech mDot™ (MTDOT Series) V. Schedule New versions are currently available for download and VI. Flashing mDot Firmware evaluation: VII. Part Numbers Impacted Release 4.0.0 (shipping in June 2021) Release 3.3.5 VIII. Mbed OS Overview IX. xDot Overview Release 4.0.0 will released into standard MultiTech product starting in June 2021. Currently, product ships with X. mDot Overview Release 3.2.1 XI. xDot Micro Developer Kit II. Suggested Action Plan XII. Additional Information Customers Review the information in this PCN and forward to Attachments others within your organization who are actively Identifying Firmware Version involved with the development of IoT applications using the MultiTech xDot and MultiTech mDot. Identifying Date of Manufacture Consider downloading the firmware available on MultiTech or Mbed websites to check compatibility mPower & mLinux Software with existing deployments. PCN 03302021-001 (Dot) Page 1 of 12 https://support.multitech.com Review the release schedule for the upcoming firmware release and understand the effect on your manufacturing and deployment schedules. Distributors Forward this announcement to others within your organization who are actively involved in the sale or support of LoRa-enabled sensors. -
Dell EMC Powerstore CLI Guide
Dell EMC PowerStore CLI Guide May 2020 Rev. A01 Notes, cautions, and warnings NOTE: A NOTE indicates important information that helps you make better use of your product. CAUTION: A CAUTION indicates either potential damage to hardware or loss of data and tells you how to avoid the problem. WARNING: A WARNING indicates a potential for property damage, personal injury, or death. © 2020 Dell Inc. or its subsidiaries. All rights reserved. Dell, EMC, and other trademarks are trademarks of Dell Inc. or its subsidiaries. Other trademarks may be trademarks of their respective owners. Contents Additional Resources.......................................................................................................................4 Chapter 1: Introduction................................................................................................................... 5 Overview.................................................................................................................................................................................5 Use PowerStore CLI in scripts.......................................................................................................................................5 Set up the PowerStore CLI client........................................................................................................................................5 Install the PowerStore CLI client.................................................................................................................................. -
The Development of Smalltalk Topic Paper #7
The Development of Smalltalk Topic Paper #7 Alex Laird Max Earn Peer CS-3210-01 Reviewer On Time/Format 1 2/4/09 Survey of Programming Languages Correct 5 Spring 2009 Clear 2 Computer Science, (319) 360-8771 Concise 2 [email protected] Grading Rubric Grading Total 10 pts ABSTRACT Dynamically typed languages are easier on the compiler because This paper describes the development of the Smalltalk it has to make fewer passes and the brunt of checking is done on programming language. the syntax of the code. Compilation of Smalltalk is just-in-time compilation, also known Keywords as dynamic translation. It means that upon compilation, Smalltalk code is translated into byte code that is interpreted upon usage and Development, Smalltalk, Programming, Language at that point the interpreter converts the code to machine language and the code is executed. Dynamic translations work very well 1. INTRODUCTION with dynamic typing. Smalltalk, yet another programming language originally developed for educational purposes and now having a much 5. IMPLEMENTATIONS broader horizon, first appeared publically in the computing Smalltalk has been implemented in numerous ways and has been industry in 1980 as a dynamically-typed object-oriented language the influence of many future languages such as Java, Python, based largely on message-passing in Simula and Lisp. Object-C, and Ruby, just to name a few. Athena is a Smalltalk scripting engine for Java. Little Smalltalk 2. EARLY HISTORY was the first interpreter of the programming language to be used Development for Smalltalk started in 1969, but the language outside of the Xerox PARC. -
Multi-Return Function Call
To appear in J. Functional Programming 1 Multi-return Function Call OLIN SHIVERS and DAVID FISHER College of Computing Georgia Institute of Technology (e-mail: fshivers,[email protected]) Abstract It is possible to extend the basic notion of “function call” to allow functions to have multiple re- turn points. This turns out to be a surprisingly useful mechanism. This article conducts a fairly wide-ranging tour of such a feature: a formal semantics for a minimal λ-calculus capturing the mechanism; motivating examples; monomorphic and parametrically polymorphic static type sys- tems; useful transformations; implementation concerns and experience with an implementation; and comparison to related mechanisms, such as exceptions, sum-types and explicit continuations. We conclude that multiple-return function call is not only a useful and expressive mechanism, at both the source-code and intermediate-representation levels, but also quite inexpensive to implement. Capsule Review Interesting new control-flow constructs don’t come along every day. Shivers and Fisher’s multi- return function call offers intriguing possibilities—but unlike delimited control operators or first- class continuations, it won’t make your head hurt or break the bank. It might even make you smile when you see the well-known tail call generalized to a “semi-tail call” and a “super-tail call.” What I enjoyed the most was the chance to reimagine several of my favorite little hacks using the new mechanism, but this unusually broad paper offers something for everyone: the language designer, the theorist, the implementor, and the programmer. 1 Introduction The purpose of this article is to explore in depth a particular programming-language mech- anism: the ability to specify multiple return points when calling a function. -
PHP String Interview Questions
By OnlineInterviewQuestions.com String Interview Questions in PHP Q1. What is String in PHP? The String is a collection or set of characters in sequence in PHP. The String in PHP is used to save and manipulate like an update, delete and read the data. Q2. How to cast a php string to integer? The int or integer used for a variable into an integer in PHP. Q3. How to perform string concatenation in PHP? The string concatenation means two strings connect together. The dot ( . ) sign used in PHP to combine two string. Example:- <?php $stringa = " creative "; $stringb = "writing "; echo $stringa . $stringb; ?> Q4. How to get php string length? To determine the string length in PHP, strlen() function used. Example:- echo strlen(“creative writing”); Q5. List some escape characters in PHP? Some list escape characters in PHP there are:- \’ \” \\ \n \t \r Q6. How to convert special characters to unicode in php? There is function json_encode() which is converted special characters to Unicode in PHP. Example:- $stringa = " I am good at smiling"; print_r(json_encode($stringa)); Q7. How to add double quotes in string in php? The double quotes in string using (" ") sign and write content under this sign. The double quotes convert variable as value. An example is below:- $str8 = " need to read data where has to go "; echo $str 8output: double quotes in the string echo “ PHP work $str8 output: PHP work need to read data where has to go Q8. Explain how php string interpolation is done? The interpolation is adding variables in among a string data. PHP parses the interpolate variables and replaces this variable with own value while processing the string. -
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.