how to interpolate recursive search in zsh

Question

I want to use an environment variable in a command with recursive search.

export RAILS_FILE_EXTENSIONS='(erb|feature|haml|jrxml|js|rake|rb|rxml|scss|xml|yml)'
ls **/*.${RAILS_FILE_EXTENSIONS}

It does not work this way. How should it look like?

Answer 1

Tell zsh to interpret RAILS_FILE_EXTENSIONS as a pattern rather than a raw string when substituting its value, with the ~ parameter expansion flag.

RAILS_FILE_EXTENSIONS='(erb|feature|haml|jrxml|js|rake|rb|rxml|scss|xml|yml)'
ls **/*.$~RAILS_FILE_EXTENSIONS