-- I'm assuming that special columns have multiple words, and single-word
-- columns are always filenames. pensieve.love won't ever create filenames
-- containing spaces.

  elseif not column_name:find(' ') then
    -- File not found
    --
    -- It makes me nervous to silently drop errors, but at this point there's
    -- really nothing actionable someone can do in response to an error.
    --
    -- Deeper issue: no way yet to communicate errors in the UI.
    --
    -- Philosophical question: what does crash-only mean if you ever run into
    -- data loss? There's a hard tension between resilience and silent failures.
    --
    -- For now I'm going to rely on all my protections against data loss
    -- elsewhere. Lines.love has never lost my data in several months of use.
    --
    -- While data loss seems unlikely, there _is_ a legitimate way you can end
    -- up with a filename that doesn't exist: start a capture, then change
    -- your mind and never type anything into it. It will continue to show as
    -- a column on the surface, but there's no file backing it. You can still
    -- edit it later and create a file for it. But if you just quit, the
    -- column will silently disappear after restart.
    print('file not found: '..column_name)