A few scientific journals mandate that papers with computational results be reproducible, with the code made available. Journals should also require that accompanying code be standard-conforming, at least for languages such as C, C++, and Fortran with ISO standards. Considering that a research project may span many years, and that compilers implement standards with a lag, flexibility should be allowed regarding which versions of the standard are acceptable. One could mandate that a Fortran-based paper published today be standard F2003, F2008, or F2018.
Journal editors and referees are interested in the scientific content of a paper, not the details of how an underlying program was written. They don’t want to bicker with authors about what features of a programming language can be used. Mandating conformance to a standard outsources the decision of what is acceptable code to a committee that has thought about such things.
Once authors are told that their papers would be published if it weren’t for features such as real*8 declarations sprinkled in their code, they will quickly fix their codes. The results of many papers depend on programming languages without an ISO standard, such as Python or Matlab. I wonder what the guidelines should be for them.
Book publishers should also have rules about language standards, since many authors and book editors are unfamiliar with them.