Backward- and forward-compatibility

[LaurentRDC]

Hello,

I would like to inquire about the possibility to increase backward- and forward-compatibility in pandoc-types. For example, in pandoc-types 1.21, changes to the AST has broken the way a few filters work. The new Table block element is not crucial for many filters (e.g. pandoc-plot or pandoc-include-code), so the breakage is artificial.

I propose that the next time the AST is changed, a new block element, Unknown, be added. Then, the function toJSONFilter could be changed so that instead of throwing an error on incompatible pandoc-types version, the Unknown block element could be used as a placeholder for AST blocks that are not decoded appropriately.

This would allow for filters to be compatible with a wider range of pandoc-types and pandoc versions.

Let me know what you think.

[jgm]

Interesting idea. I don't really know what I think. Probably this should be raised for discussion on pandoc-discuss.

[LaurentRDC]

This topic is visible here.

[tarleb]

Orthogonal to the solution proposed here, but aiming to solve the same problem: ast-migrator.