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The approach for fine-grained parallelism in Ada presented at the last Real-Time Ada Workshop has been revised, both in terms of the language mechanisms to specify parallelism, as well as in terms of the underlying execution model. This paper summarizes the current state of the proposal, further detailing how programmers can control the behavior of the parallel execution, and discussing the issues which are still open.

Given the large focus on software vulnerabilities in the current market place, ISO/IEC JTC 1/SC 22/WG 23 has developed a Technical Report (TR) on Vulnerabilities [1]. This TR contains vulnerabilities that may be applicable to a programming language or application. This article provides a synopsis of these vulnerabilities with respect to the Ada programming language [2].

Ada 2005 adds an important capability to the language by allowing the construction and return of an object of a limited type by a function. New syntax for an extended return statement was added to enhance this capability further. This capability to return newly constructed objects of a limited type from a function, when combined with the additional capability to use aggregates to construct objects of a limited type, goes a long way to making use of limited types far more friendly and effective. Although the extended return statement and the associated ability to construct and return objects of a limited type brings new power to Ada, it also brings new choices and challenges to the Ada compiler implementor, when trying to decide how best to implement this feature. This presentation will review some of these alternatives, and present a high-level description of one particular approach based on the notion of an object creation context (OCC) which is designed to minimize the complexity of the generated code while providing an efficient and flexible implementation.

Abstract: We have used peripheral blood T-lymphocyte cultures to analyze the hprt mutation in two Lesch-Nyhan syndrome males who are cousins and to confirm the carrier status of female members of the family. Both cDNA and genomic DNA sequencing studies show that this patient carries a hitherto undescribed single base deletion in the exon 5 donor splice site sequence (15:+1, δG, base number 31635). The largest cDNA product contained all nine hprt exons plus an insertion of 66 bases of intron 5, consistent with the use of a cryptic splice site in intron 5 (aag67/gtaagc). This splicing error would result in a chain terminating codon immediately after exon 5 (15:2–4, taa) and predicts a polypeptide of 133 amino acids. This loss of the normal splice donor site also results in multiple hprt mRNA species, combining the use of the cryptic splice site in intron 5 and splicing errors involving exons 2–6. In addition to defining a new Lesch-Nyhan mutation (hprtHenryville), these results provide insight into aberrant splicing of hprt mRNA in T-lymphocytes.

This tutorial provides an opportunity to experiment with a new language designed to support the safe, secure, and productive development of parallel programs. ParaSail is a new language with pervasive parallelism coupled with extensive compile-time checking of annotations in the form of assertions, preconditions, postconditions, etc. ParaSail does all checking at compile time, and eliminates race conditions, null dereferences, uninitialized data access, numeric overflow, out of bounds indexing, etc. as well as statically checking the truth of all user-written assertions. After a short introduction to the language, attendees will receive a prototype ParaSail compiler and an accompanying ParaSail Virtual Machine interpreter for writing and testing ParaSail programs. The tutorial/workshop will finish with a group discussion and feedback on the experience of using this new language.

In this extended abstract, we describe the use of Ada 95 in a Compiler Construction Course.

This workshop position paper discusses two alternative approaches to enhancing exception support. The first approach is based on a syntax extension, and is very similar to an approach proposed early in the Ada 9X process. The second approach is based on adding a child package to Ada.Exceptions to support raising an exception and associating an Ada object of any type that is an extension of a particular root type.