A Proposal for a Revision of ISO Modula-2

TL;DR

This paper discusses deficiencies in the ISO Modula-2 standard and proposes a limited revision focused on the core language to improve clarity and consistency, without addressing the standard library.

Contribution

It introduces a feasible revision plan for the core language of ISO Modula-2 to address known issues without extensive overhaul.

Findings

Identified ambiguities in the current standard

Proposed specific revisions for core language improvements

Highlighted the need for ongoing standard maintenance

Abstract

The Modula-2 language was first specified in [Wir78] by N. Wirth at ETH Zurich in 1978 and then revised several times. The last revision [Wir88] was published in 1988. The resulting language reports included ambiguities and lacked a comprehensive standard library. To resolve the ambiguities and specify a comprehensive standard library an ISO/IEC working group was formed and commenced work in 1987. A base standard was then ratified and published as IS 10514-1 in 1996 [JTC96]. Several conforming compilers have since been developed. At least five remain available of which at least three are actively maintained and one has been open sourced. Meanwhile, various deficiencies of the standard have become apparent but since its publication, no revision and no maintenance has been carried out. This paper discusses some of the deficiencies of IS 10514-1 and proposes a limited revision that could be carried out with moderate effort. The scope of the paper has been deliberately limited to the core language of the base standard and therefore excludes the standard library.