[falsedan]

Don't all the languages which support complex regex also support composing regexes from objects/strings?

e.g.

  /\A\s*\d{3,5}\.\d{2}\t\(?:(['"])(?:[\s\w]|\\\1)+\1|[^'"]+)\t[A-Z0-9]+\s*\Z/

would be written as

  $ws                   = /\s*/;
  $sep                  = /\t/;
  $cost                 = /\d{3,5} [.] \d\d/x;
  $quoted_description   = /
    (['"])       # opening quote; remember this for later
      (?:        # (capture groups, don't read this)
         [\w\s]  #   a chars or space
         |       #   OR
         [\\] \1 #   backslash-escaped quote, same as opening
      )+         # (description can't be empty)
    \1           # closing quote, matching opening
  /x;
  $unquoted_description = /[^'"]+/;
  $description          = /(?: $quoted_description | $unquoted_description )/x;
  $SKU                  = / [[:upper:][:digit:]]+ /x;

  /\A $ws $cost $sep $description $sep $SKU $ws \Z/x