m[
  \@include \s       ## the introducer followed by a space
  (                  ## capture
      '[^']+'        ## A single quoted string with no embedded single quotes
  |                  ## or
      "[^"]+"        ## a double quoted string with no embedded double quotes
  |                  ## or
      .+? (?<!\\)    ## a min length string that ends in a space that isn't escaped
  )
  \s
]gx;;