Programming factors - language features that help explain programming complexity

This is the 23rd Self-Assessment Procedure. 1 The purpose of this procedure is to let its readers test their knowledge of some of the more important features of significant programming languages. The features of imperative languages like Fortran, Algol 60, PL/I, Pascal, Modula-2, C, and Ada considered are data types, data structures, control structures, program units, scope of names, and parameter passing. Some of the corresponding features of functional languages like Lisp, logic programming languages like Prolog, and ohject-oriented programming languages like C++ and Smalltalk, are reviewed. Finally brief consideration is given to syntax and semantics, chiefly by reference to the Backus-Naur form, BNF. The features of programming languages affect all aspects of programming, including the ease of writing and maintaining programs, the reliahility of software, and the efficiency and portability of programs. Knowledge of programming language concepts and constructs is of importance to software developers, programmers, and designers of programming languages and compilers. The topic of this procedure should be of interest to any computer science student or practitioner who wishes to test his or her knowledge and learn more about one of the most important and broad areas in the computer field. The language used most often in the questions is Pascal, with Ada, Lisp, and Prolog also featured prominently. A glossary is included which defines some of the terms used in the procedure. The questions are either multiple-choice or short answer. Some of the multiple-choice questions allow for more than one correct answer.

Programming language researchers often study real-world projects to see how language features have been adopted and are being used. Typically researchers choose a small number of projects to study, due to the immense challenges associated with finding, downloading, storing, processing, and querying large amounts of data. The Boa programming language and infrastructure was designed to solve these challenges and allow researchers to focus on simply asking the right questions. Boa provides a domain-specific language to abstract details of how to mine hundreds of thousands of projects and also abstracts how to efficiently query that data. We have previously used this platform to perform a large study of the adoption of Java's language features over time. In this demonstration, we will show you how we used Boa to quickly analyze billions of AST nodes and study the adoption of Java's language features.

Usability is an important feature for programming languages, and user evaluations can provide invaluable feedback on language design. However, user studies which compare programming languages or systems are often very expensive and typically inconclusive. In this paper, we posit that discount usability methods can be successfully applied to programming languages concepts such as language features. We give examples of useful feedback received from applying heuristic evaluation to two language features targeted at parallel programming.

This study aimed to determine if short-duration procedural sedation in children with propofol is related to an adverse metabolic stress response measured by serum lactate. Propofol infusion syndrome is associated with high-dose and long-duration infusion. It has not been studied with short-duration, outpatient propofol administration. This was a prospective, longitudinal study that included 50 patients between the ages of 2 and 18 years who were undergoing outpatient procedural sedation with propofol at a pediatric sedation unit. Patients received bolus or bolus and continuous infusion doses of propofol. Serum lactate values were obtained before and after the patients' sedated procedures. The average length of procedure was 40.3 minutes, and the mean dose of propofol per patient was 8.2 mg/kg. The highest measured lactate value was 1.8 mmol/L. The average (SD) preprocedure and postprocedure lactate values were 1.0 (0.3) and 0.7 (0.2) mmol/L, respectively, resulting in an overall significant decrease in lactate of -0.3 (0.3) mmol/L (P < 0.001). There was a significant (P = 0.01) positive relationship between age and postprocedure lactate value, when controlling for the length of the procedure in a multivariable regression. No significant association was found between propofol dosage and length of the procedure with lactate values. In this study, we did not find a significant increase in metabolic stress, measured by serum lactate. Using propofol for short-duration procedural sedation may not carry similar risks for propofol infusion syndrome to those for long-duration/high-dose infusion therapy.

Background: Non-valvular atrial fibrillation (AF) is a leading cause of embolic stroke, especially in the elderly population. The vast majority of thrombo-emboli in AF patients originate within the left atrial appendage (LAA). Effective and complete isolation of the LAA has been demonstrated to have a similar stroke-reduction effect as chronic anticoagulation. This study presents our initial experience with a novel minimally-invasive video-assisted (MIVA) thoracoscopic approach to epicardially isolate the LAA using the AtriClip device. Methods: Six consecutive AF patients (mean age 73.6 years, 3 of 6 male) with contra-indication to systemic anticoagulation underwent epicardial ligation of LAA using the AtriClip device. Procedure involved two 5mm ports and one 15mm port with application of the device at the base of the LAA under direct visualization. Immediate intra-operative confirmation of LAA isolation via trans-esophageal echocardiography (TEE) was obtained. Anticoagulation was not restarted post-operatively. Results: Average procedure length was 43mins and average length of stay was 72hours. All six patients had a non-complicated post-operative course. No stroke, myocardial infarction, renal failure or re-operation was encountered. No transfusions were needed. All patients were extubated in the operating room at conclusion of procedure and were ambulatory on the first postoperative day. 3 of 6 patients experienced excessive pleural drainage lasting 2-4 days postoperatively. TEE confirmation of complete LAA obliteration was achieved in all patients. Conclusions: MIVA LAA ligation appears to be a safe, effective and simple procedure to isolate the LAA in AF patients with contra-indication to anticoagulation. A multi-institutional trial to assess the efficacy of MIVA LAA ligation as a stroke prevention strategy is warranted and forthcoming.

Why do some programming languages fail and others succeed? What does the answer tell us about programming language design, implementation, and principles? To help answer these and other questions, we argue for examining the sociological groundings of programming language theory: socio-PLT.Researchers in the social sciences have studied adoption in many contexts. We show how their findings are applicable to programming language design. For example, many programming language features provide benefits that programmers cannot directly or immediately observe and therefore may not find compelling. From clean water to safe sex, the health community has repeatedly identified and surmounted similar observability barriers. We use such results from outside of programming language theory to frame a research agenda that should help us understand the social foundations of languages. Finally, we examine implications of our approach, such as for the design space of language features and the assessment of scientific research into programming languages.

Small cell lung cancer survival in elderly patients at UHSM UK

Associated with every programming language is a style of programming which is encouraged by the semantic and syntactic features of this language. We are all familiar with the phenomenon of a FORTRAN programmer approaching APL for the first time and writing correct APL programs which are nevertheless emphatically criticized for not displaying the proper APL style. Indeed we may consider this 'APL style' to be the most important contribution of the language to the art of programming, rather than the specific language features out of which this style emerges. Controversies about the value of APL (and other programming languages) focus precisely around this issue of style. It is also around this issue that we want to center our presentation of SETL.Briefly stated, SETL is a very-high level programming language whose basic semantic constructs are those of the mathematical theory of sets. Primitive operations in SETL include set membership, union, intersection, power set construction, etc. SETL provides two basic aggregate data types : unordered sets, and sequences, or tuples. The elements of sets and the components of tuples can themselves be of arbitrary type, including sets and tuples. In particular, sets of pairs (i.e. tuples of length 2) can be used as maps with perfectly general domain and range types.

Software companies such as Microsoft periodically release new versions of the .NET framework and C# language suites. New features are introduced in each of these new releases. Currently, there is little or no empirical analysis of the adoption of .NET framework and C# programming language features and studies on how successfully those features are accepted by the community. The aim of this work is to create a set of long term statistics about the use of the new .NET and C# language features across existing popular libraries.

Su1320 SAFETY OF EUS GUIDED GALL BLADDER DRAINAGE IN GRADE 4 CHOLECYSTITIS

The past few years have witnessed an increased understanding of the relationship between programming languages and problem solving. Programming is now understood to be a rather difficult task which requires the simultaneous application of principles, skills, and art. Computer scientists have recognized that the features of a programming language can have a significant effect upon the ease with which reliable programs can be developed. It has also been observed that certain languages and language features are particularly well suited for the use of systematic programming techniques, while others hinder or discourage such discipline. Of course, it is possible to write well-structured, clearly organized programs in any programming language, but such programs have often been the exception rather than the rule.

Modular language implementation in Rascal – experience report

Scala is a new programming language bringing together object-oriented and functional programming. Its defining features are uniformity and extensibility. Scala offers great flexibility for programmers, allowing them to grow the language through libraries. Oftentimes what seems like a language feature is in fact implemented in a library, effectively giving programmers the power of language designers. The downside of this flexibility is that familiar looking code may hide unexpected performance costs. It is important for Scala compilers to bring down this cost as much as possible. We identify several areas of impact for Scala performance: higher-order functions and closures, and generic containers used with primitive types. We present two complementary approaches for improving performance in these areas: optimizations and specialization. Compiler optimization can bring down the cost through a combination of aggressive inlining of higher-order functions, an extended version of copy-propagation and dead-code elimination. Both anonymous functions and boxing can be eliminated by this approach. We show on a number of benchmarks that these language features can be up to 5 times faster when properly optimized, on current day JVMs. We propose a new approach to compiling parametric polymorphism for performance at primitive types. We mix a homogeneous translation scheme with user-directed specialization for primitive types. Type parameters may be annotated to require specialization of code depending on them. We propose definition-site specialization for primitive types, achieving separate compilation and no boxing when both the definition and call site are specialized. Specialized classes are compatible with unspecialized code, and specialization agnostic code can work with specialized instances, meaning that specialization is opportunistic. We present a formalism of a small subset of Scala with specialization and prove that specialization preserves types. We implemented this translation in the Scala compiler and report on improvements on a set of benchmarks, showing that specialization can make programs more than two times faster.

Programming languages with sufficiently expressive type systems provide users with different means of data ‘bundling’. Specifically, in dependently-typed languages such as Agda, Coq, Lean and Idris, one can choose to encode information in a record either as a parameter or a field. For example, we can speak of graphs over a particular vertex set, or speak of arbitrary graphs where the vertex set is a component. These create isomorphic types, but differ with respect to intended use. Traditionally, a library designer would make this choice (between parameters and fields); if a user wants a different variant, they are forced to build conversion utilities, as well as duplicate functionality. For a graph data type, if a library only provides a Haskell-like typeclass view of graphs over a vertex set, yet a user wishes to work with the category of graphs, they must now package a vertex set as a component in a record along with a graph over that set. We design and implement a language feature that allows both the library designer and the user to make the choice of information exposure only when necessary, and otherwise leave the distinguishing line between parameters and fields unspecified. Our language feature is currently implemented as a prototype meta-program incorporated into Agda’s Emacs ecosystem, in a way that is unobtrusive to Agda users.

An industrial robot is an automatic multi-purpose manipulator, programmable in three or more axes. A program written in a high-level programming language controls these robots, many of these programs involve multiple tasks controlling different robots. Data races are a common problem in concurrent and multi-threaded programming and they are of big concern for the multi-task industrial robotics programmers too. We present a static analysis method for detecting data races in multi-task programs for industrial robots. We propose a technique based on a relation that models when two or more statements from a task occur in between two or more statements in another task. Our static analysis is preceded by a manual, dynamic analysis step for ensuring consistency among tasks for one of the constructs which involves a task waiting for a particular duration. We define a set of not-occurs in-between rules to detect whether two statements in different tasks may race with each other. We have developed a prototype implementation of our tool for the Rapid programming language that is used to program industrial robots of ABB. Rapid has all the features of a typical programming language for industrial robots and hence our race detection framework will generalize to any programming language for industrial robots.