Re: [h5md-user] Make "time" optional?

[Pierre de Buyl]

On Wed, Jul 16, 2014 at 04:45:33PM +0200, Felix Höfling wrote:
> 
> Semantic versioning has basically been invented for software. If a
> future software version can process old input files, it is backwards
> compatible. In this sense, a file reader for the new file format
> processes old files as new ones (i.e., without extra hooks).
> However, there may be different interpretations in the context of a
> file format.
> 
> The interpretation that old readers must be able to handle new files
> drastically limits the possible "minor" changes to the file format,
> and is IMO useless. Translating to the software domain, it means
> that old software must be able to process future input files.
> 
> To make things more specific: making a previously mandatory field
> optional is backwards compatible. Changing the overall tree
> structure (or just renaming /particles → /atoms) is not.
> 

It is true that the proposed change allows H5MD x.y > 1.0 to read 1.0 files.