Neverlang 2 – Componentised Language Development for the JVM

International audienceTraditional compiler development is non-modular. Although syntax extension and DSL embedding is making its way back in modern language design and implementation, componentisation in compiler construction is still an overlooked matter. Neverlang is a language development framework that emphasises modularity and code reuse. Neverlang makes extension, restriction and feature sharing easier, by letting developers define language components in distinct, independent units, that can be compiled independently and shared across different language implementations, even in their compiled form. The semantics of the implemented languages can be specified using any JVM-supported language. In this paper we will present the architecture and implementation of Neverlang 2, by the help of an example inspired by mobile devices and context-dependent behaviour. The Neverlang framework is already being employed successfully in real-world environments

FTREE: Stata module to save directory information in text file (Windows only)

save informations of the current directory into txt file named mydir.file management, directory

Principled Syntactic Code Completion using Placeholders

Principled syntactic code completion enables developers to change source code by inserting code templates, thus increasing developer efficiency and supporting language exploration. However, existing code completion systems are ad-hoc and neither complete nor sound. They are not complete and only provide few code templates for selected programming languages. They also are not sound and propose code templates that yield invalid programs when inserted. This paper presents a generic framework that automatically derives complete and sound syntactic code completion from the syntax definition of arbitrary languages. A key insight of our work is to provide an explicit syntactic representation for incomplete programs using placeholders. This enables us to address the following challenges for code completion separately: (i) completing incomplete programs by replacing placeholders with code templates, (ii) injecting placeholders into complete programs to make them incomplete, and (iii) introducing lexemes and placeholders into incorrect programs through error-recovery parsing to make them correct so we can apply one of the previous strategies. We formalize our framework and provide an implementation in Spoofax.Programming Language