Recovering Grammar Relationships for the Java Language Specification

Grammar convergence is a method that helps discovering relationships between different grammars of the same language or different language versions. The key element of the method is the operational, transformation-based representation of those relationships. Given input grammars for convergence, they are transformed until they are structurally equal. The transformations are composed from primitive operators; properties of these operators and the composed chains provide quantitative and qualitative insight into the relationships between the grammars at hand. We describe a refined method for grammar convergence, and we use it in a major study, where we recover the relationships between all the grammars that occur in the different versions of the Java Language Specification (JLS). The relationships are represented as grammar transformation chains that capture all accidental or intended differences between the JLS grammars. This method is mechanized and driven by nominal and structural differences between pairs of grammars that are subject to asymmetric, binary convergence steps. We present the underlying operator suite for grammar transformation in detail, and we illustrate the suite with many examples of transformations on the JLS grammars. We also describe the extraction effort, which was needed to make the JLS grammars amenable to automated processing. We include substantial metadata about the convergence process for the JLS so that the effort becomes reproducible and transparent

Deriving tolerant grammars from a base-line grammar

A grammar-based approach to tool development in re- and reverse engineering promises precise structure awareness, but it is problematic in two respects. Firstly, it is a considerable up-front investment to obtain a grammar for a relevant language or cocktail of languages. Existing work on grammar recovery addresses this concern to some extent. Secondly, it is often not feasible to insist on a precise grammar, e.g., when different dialects need to be covered. This calls for tolerant grammars. In this paper, we provide a well-engineered approach to the derivation of tolerant grammars, which is based on previous work on error recovery, fuzzy parsing, and island grammars. The technology of this paper has been used in a complex Cobol restructuring project on several millions of lines of code in different Cobol dialects. Our approach is founded on an approximation relation between a tolerant grammar and a base-line grammar which serves as a point of reference. Thereby, we avoid false positives and false negatives when parsing constructs of interest in a tolerant mode. Our approach accomplishes the effective derivation of a tolerant grammar from the syntactical structure that is relevant for a certain re- or reverse engineering tool. To this end, the productions for the constructs of interest are reused from the base-line grammar together with further productions that are needed for completion

Software maintenance: generating front ends for cross referencer tools

This thesis surveys the activities performed in software maintenance and identifies some of the software tools which can be utilised by the maintenance programmer. The most expensive phase of software maintenance is surveyed in more detail and tools to support this activity are identified. A new class of cross referencer tool was designed and investigated. The novel aspect of the cross referencer is that it can be used on more than one language, by utihzing grammar driven generators to customize and make maximum re-use of the language independent components, allowing language specific implementations to be generated with minimal effort. The cross referencer also extends an idea of having different levels of detail in cross reference listings by allowing the tool implementor to specify the contents of each level of detail. A proposed experimental toolkit for the automatic construction of these cross referencer front end tools, from non procedural specifications, is designed and investigated

A STUDY ON VARIOUS PROGRAMMING LANGUAGES TO KEEP PACE WITH INNOVATION

A programming language is a formal computer language designed to communicate instructions to a machine, particularly a computer. Programming languages can be used to create programs to control the behaviour of a machine or to express algorithms. The earliest known programmable machine preceded the invention of the digital computer and is the automatic flute player described in the 9th century by the brothers Musa in Baghdad, "during the Islamic Golden Age". From the early 1800s, "programs" were used to direct the behavior of machines such as Jacquard looms and player pianos. Thousands of different programming languages have been created, mainly in the computer field, and many more still are being created every year. Many programming languages require computation to be specified in an imperative form (i.e., as a sequence of operations to perform) while other languages use other forms of program specification such as the declarative form (i.e. the desired result is specified, not how to achieve it). The description of a programming language is usually split into the two components of syntax (form) and semantics (meaning). Some languages are defined by a specification document (for example, the C programming language is specified by an ISO Standard) while other languages (such as Perl) have a dominant implementation that is treated as a reference. Some languages have both, with the basic language defined by a standard and extensions taken from the dominant implementation being common. An attempt is made in this paper to have a study on various programming languages

Integration of Virtual Programming Lab in a process of teaching programming EduScrum based

Programming teaching is a key factor for technological evolution. The efficient way to learn to program is by programming and hard training and thus feedback is a crucial factor in the success and flow of the process. This work aims to analyse the potential use of VPL in the teaching process of programming in higher education. It also intends to verify whether, with VPL, it is possible to make students learning more effective and autonomous, with a reduction in the volume of assessment work by teachers. Experiments were carried out with the VPL, in the practical-laboratory classes of a curricular unit of initiation to programming in a higher education institution. The results supported by the responses to surveys, point to the validity of the model

An Exploration Of The Effects Of Enhanced Compiler Error Messages For Computer Programming Novices

Computer programming is an essential skill that all computing students must master and is increasingly important in many diverse disciplines. It is also difficult to learn. One of the many challenges novice programmers face from the start are notoriously cryptic compiler error messages. These report details on errors made by students and are essential as the primary source of information used to rectify those errors. However these difficult to understand messages are often a barrier to progress and a source of discouragement. A high number of student errors, and in particular a high frequency of repeated errors – when a student makes the same error consecutively – have been shown to be indicators of students who are struggling with learning to program. This instrumental case study research investigates the student experience with, and the effects of, software that has been specifically written to help students overcome their challenges with compiler error messages. This software provides help by enhancing error messages, presenting them in a straightforward, informative manner. Two cohorts of first year computing students at an Irish higher education institution participated over two academic years; a control group in 2014-15 that did not experience enhanced error messages, and an intervention group in 2013-14 that did. This thesis lays out a comprehensive view of the student experience starting with a quantitative analysis of the student errors themselves. It then views the students as groups, revealing interesting differences in error profiles. Following this, some individual student profiles and behaviours are investigated. Finally, the student experience is discovered through their own words and opinions by means of a survey that incorporated closed and open-ended questions. In addition to reductions in errors overall, errors per student, and the key metric of repeated error frequency, the intervention group is shown to behave more cohesively with fewer indications of struggling students. A positive learning experience using the software is reported by the students and the lecturer. These results are of interest to educators who have witnessed students struggle with learning to program, and who are looking to help remove the barrier presented by compiler error messages. This work is important for two reasons. First, the effects of error message enhancement have been debated in the literature – this work provides evidence that there can be positive effects. Second, these results should be generalisable at least in part, to other languages, students and institutions