How to tell if column is standalone, or referencing other columns

[yahooguntu]

On two occasions I have entered a command, only for nothing to happen. Both times it was because my columns were actually computed from other columns, and so weren't editable. I had to freeze them first with ' (or the new z') before I could change them via commands. Is there an obvious way to tell when this is happening that I'm just not seeing?

My specific workflow was:

• Open file
• All data is in one big column; split on space by doing :<space>
• Expand grouped columns with g(
• Navigate to a column and attempt a regex replace with g*<search text><tab><replace text><enter>
• Nothing happens
• Figure out the column isn't frozen; freeze column with z'
• Redo regex replace; it now works

[midichef]

Right now, there is no obvious way to tell that the results of : and ( etc are not editable. But you're right, it would be better if there were such a way.

Such a visual cue has recently been added to expression columns that result from =. The column title is drawn in red. This feature is in the develop branch of visidata that will be released as version 3.4.

I'll submit a PR to add similar coloring for regex columns and expanded columns.

[midichef]

Okay this has been fixed in the latest develop branch which you can install with:
pip3 install git+https://github.com/saulpw/visidata.git@develop