Introduction - The LDTA tool challenge

Compilers are one of the cornerstones of Computer Science and in particular for Software Development. Compiler research has a long tradition and is very mature. Nevertheless, there is hardly any standardization with respect to formalisms and tools for developing compilers. Comparison of formalisms and tools to describe compilers for languages is not a simple task. In 2011 the Language Descriptions Tools and Applications community created a challenge where formalisms and tools were to be used in constructing a compiler for the Oberon-0 language. This special issue presents the tool challenge, the Oberon-0 language, various solutions to the challenge, and some conclusions. The aim of the challenge was to develop the same compiler using different formalisms to learn about these approaches in a concrete setting.