Regex

[NicoLaval]

Reference manual, page 116:

match_characters returns TRUE if op matches the regular expression regexp, FALSE otherwise. The string regexp is an Extended Regular Expression as described in the POSIX standard. Different implementations of VTL may implement different versions of the POSIX standard therefore it is possible that match_characters may behave in slightly different ways.

This is a concern in terms of reproducibility.

Can we be more precise in the specification in order to share the same standard?