Memoizing a monadic mixin DSL

Modular extensibility is a highly desirable property of a domain-specific language (DSL): the ability to add new features without affecting the implementation of existing features. Functional mixins (also known as open recursion) are very suitable for this purpose. We study the use of mixins in Haskell for a modular DSL for search heuristics used in systematic solvers for combinatorial problems, that generate optimized C++ code from a high-level specification. We show how to apply memoization techniques to tackle performance issues and code explosion due to the high recursion inherent to the semantics of combinatorial search. As such heuristics are conventionally implemented as highly entangled imperative algorithms, our Haskell mixins are monadic. Memoization of monadic components causes further complications for us to deal with

Constraint detection in natural language problem descriptions

Modeling in constraint programming is a hard task that requires considerable expertise. Automated model reformulation aims at assisting a naive user in modeling constraint problems. In this context, formal specification languages have been devised to express constraint problems in a manner similar to natural yet rigorous specifications that use a mixture of natural language and discrete mathematics. Yet, a gap remains between such languages and the natural language in which humans informally describe problems. This work aims to alleviate this issue by proposing a method for detecting constraints in natural language problem descriptions using a structured-output classifier. To evaluate the method, we develop an original annotated corpus which gathers 110 problem descriptions from several resources. Our results show significant accuracy with respect to metrics used in cognate tasks

A Regular Matching Constraint for String Variables

Using a regular language as a pattern for string matching is nowadays a common-and sometimes unsafe-operation, provided as a built-in feature by most programming languages. A proper constraint solver over string variables should support most of the operations over regular expressions and related constructs. However, state-of-the-art string solvers natively support only the membership relation of a string variable to a regular language. Here we take a step forward by defining a specialised propagator for the match operation, returning the leftmost position where a pattern can match a given string. Empirical evidences show the effectiveness of our approach, implemented within the constraint programming framework, and tested against state-of-the-art string solvers.</p

A Scala Embedded DSL for Combinatorial Optimization in Software Requirements Engineering

The goal of the presented work is to provide support for software requirements engineering domain experts in modeling combinatorial optimization problems that arise in requirements prioritization and release planning. A Domain-Specific Language (DSL), called reqT/CSP, is presented that integrates constraints modeling with requirements modeling. The DSL is embedded in the object-functional Scala programming language. The DSL is demonstrated using principal examples of priority ranking and release planning. Benefits, limitations and future work are discussed