Pros and cons of this approach

Pros

• It works

• Time efficient

  • Even complicated compound languages can be defined within minutes

  • No conversions, no adjustments of original schemas

  • Rewriting the NVDL definition for a different compound language (different parent language, additional language involved or different contexts) in minutes

• Less knowledge required

  • The previous NVDL script is composed only of 7 elements and the whole NVDL specification only has 10 more

  • NVDL script authors don't need to have any knowledge of the schema languages used for referenced grammars

• Fully reusable

  • The schemas for involved languages can be fully reused as they are (even at their original location)

  • No need to download them, convert them or adjust them in any way

  • Whether schemas are written in W3C XML Schema, RELAX NG or Schematron, no matter NVDL can handle all of them in one validation process

  • They may be reused as they are for any compound language definition imaginable

• Easy to read and understand

  • NVDL scripts are easy to read (just few elements)

  • They contain only information about the compound language (not the individual languages)

Cons

• I don't see any significant cons

• Few little issues are address in our extensions to the NVDL specification