Evolutionary User Strategery

[Fairchild]

LilyPonders -

Users dealing with LilyPond as it evolves are presented with difficult choices, none good.

If one knows a score will be completed quickly, never be revisited, and components of the code structure never will be reused, the choice is easy: save and share graphics only, dump the ly files for completed scores, and move on to the latest stable version.  I'm not that prescient.

Constantly adopting the latest version allows use of the latest features, feedback helps the developers, and the developers provide support.  However, modifying 'finished' scores to be acceptable by the latest version is not reasonable.  Upgrade modifications require significant effort.  The convert-ly program helps, but misses a lot. 

It is tempting to select a stable version and stick with it.  Scores can be revisited easily.  Syntax and semantics are stable.  Downside: the feature set never gets better and support will fade away unless a sufficient number of users make the same choice and help each other.

It is possible to maintain multiple LilyPond versions.  This allows revisiting old scores, but at a price.  The operational environment becomes more and more confusing as versions accumulate.

I have coded tens of scores, most with version 2.4.6, and spent several hours attempting to move just one (a smaller one) of them to 2.8.5.  After using convert-ly and correcting for its errors, much remains to be done, especially to position the right text font.  Conclusion: repetitive conversion of scores is untenable.

The only reasonable solution is to maintain upward compatibility in the LilyPond processor.  New features should be added without changing existing syntax.  If it is deemed absolutely necessary to change semantics or define conflicting syntax, provide for optional interpretations based on the version specified.  Older ly files should generate consistent results as LilyPond migrates.  More exhaustive regression tests are necessary.

If you can identify a better way, or have other comments, please respond.

                                   - Bruce