CoordCellRef: Fix adding the optional finder

[alexanderpann]

This PR replaces the not working optional finder cell of the CoordCellRef editor with a transformation menu so that the finder can be added through the code completion menu of the cell instead of typing "/" before the cell.
I changed it because I couldn't get the optional cell working. The missing spaces in the editor (punctuation-x: true) prevent the side transformation to be executed. Fixes #559.

[brucetrask]

@alexanderpann and @sergej-koscejev Thanks very much for the fix. I tried it and it works great. Should we create an issue for the broken optional cell in the grammar cells language? I don't know where that language is or know much about it but I heard it is something useful I should be using. Is it also part of iets3.opensource?

[alexanderpann]

@alexanderpann and @sergej-koscejev Thanks very much for the fix. I tried it and it works great. Should we create an issue for the broken optional cell in the grammar cells language? I don't know where that language is or know much about it but I heard it is something useful I should be using. Is it also part of iets3.opensource?

Actually, the old behavior of the optional cell was wrong, which was fixed a while ago. The way the cell was used is just not compatible with the latest version of grammar cells. There is nothing else that needs to be fixed.

[brucetrask]

@alexanderpann and @sergej-koscejev Ok. Thanks. One last follow up just to make sure I am understanding (I am a bit new to MPS). So, could I use the optional grammar cell facility in this sheets use case or is it that use case which is not compatible with the grammar cells I have with 2021.1? In other words, you mentioned you couldn't get the optional cell working in your comment above. Is that because the use in the sheets is not possible or something else? Just wanted to understand.

[alexanderpann]

The optional cell uses side transformations. Normally they work, but this editor uses punctuation-left:true and punctuation-right:true in some cells which disallows the cursor at those positions. As a result, the side transformations can't be executed because you are not allowed to enter the triggering text (in this case: "/").

[brucetrask]

Thanks @alexanderpann . Appreciate your help on this.

[wsafonov]

Looks good in general. Just couple of minor questions:

• is there really a need for the additional vertical collection wrapper in the editor?
• in case there is a already cell specified without a finder, would just typing / before that add the finder as expected? I'm not sure if this worked before with an optional cell, but just for the sake of completeness.
• would it be possible to add some editor tests for this scenario? To ensure we avoid regression in this specific editor behaviour in the future.

[arimer]

@alexanderpann I am not sure here. Where the questions/findings of @wsafonov already addressed in this PR or are they missing?

[alexanderpann]

IMO, I've addressed all points.

[alexanderpann]

@arimer I've rebased the PR for 2021.3. It could be merged.