Comment (by Roland Haas):

Pull request is here: https://bitbucket.org/cactuscode/cactus/pull-requests/75/rhaas-envexp/diff

I have done my very best to make the regular expression as incomprehensible as Perl lets me (well I could pick a separator more confusing than # I guess, but am doing a good job otherwise I think).

Comments on both whether this is a desirable feature to begin with and on the implementation would be welcome.

Please review.

--
Ticket URL: https://bitbucket.org/einsteintoolkit/tickets/issues/2312/expand-env-variables-in-rhs-of-option-list