Kay Robbins

My concern is not tsv columns in general but the "onset" column in particular: [https://bids-specification.readthedocs.io/en/stable/glossary.html#onset-columns](https://bids-specification.readthedocs.io/en/stable/glossary.html#onset-columns). This description mentions positive and negative values very specifically and what the behavior should be.

Let me give a little more background on this issue. In the past, the HED validators have assumed that the `onset` columns do not allow "n/a". However, @yarikoptic has a...

It can be negative too. Just add: >A `n/a` value indicates the onset time is unknown or unavailable. After >Onset (in seconds) of the event, measured from the beginning of...

More worrisome is overriding of `onset` and `duration` -- which are assumed to have units of seconds.

I wanted to confirm that the `HED` column would be an optional column that would not be allowed to be overridden. Otherwise the HED validator and other tools would have...

@happy5214 and I had a detailed discussion today about this. We are keeping `HED_ERROR`, `HED_WARNING`, and `HED_INTERNAL_ERROR` error as the codes. The other errors are either not used or are...

> Should `character` also be `number | string`? Or, if these are ranges, should we do `number | [number, number]` and HED can use arrays instead of converting to strings?...

> `character` (which I'm assuming is the index) Just a note: In 4.0.0, the `character` is now a string with the actual problematic character. The reason for the change was...

This issue was answered very satisfactorily and can now be closed (thank you!). However, I just wanted to verify that this principle has been incorporated into the BIDS-validator.

I would appreciate it. I am not positive at this point that all case sensitivity issues are caught by the validator. It would be nice for downstream tool developers to...