Enable consistent navigation with the keyboard

[severo]

Ideally, all the actions could be done with the keyboard. Some of them:

Column actions (top row):

• order by a column - see sort columns with the keyboard #152
• remove sort - see sort columns with the keyboard #152

Also, for Columns, maybe:

• resize (and auto resize) the column with keyboard - see Navigate the table with keyboard #140

Cells:

• go to a specific cell - see Navigate the table with keyboard #140
• scroll to fetch more data - see Navigate the table with keyboard #140
• handle key down on a cell - see Add a prop to handle key down on a cell #153. It can handle the following cases, that are not part of hightable (can be implemented in hyperparam-cli):
  • "open" a cell (currently: double click or center mouse click) -
  • close a cell with escape
  • copy to clipboard? https://www.w3.org/WAI/ARIA/apg/practices/keyboard-interface/#keyassignmentconventionsforcommonfunctions

Row selection (left column) - see https://www.w3.org/WAI/ARIA/apg/patterns/grid/#datagridsforpresentingtabularinformation for the shortcuts to support:

• select a row
• select multiple rows
• select/unselect all the rows

[severo]

some interesting ideas: https://inclusive-components.design/data-tables/

also see

• https://developer.mozilla.org/en-US/docs/Learn_web_development/Core/Structuring_content/Table_accessibility
• https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Reference/Roles/grid_role
• https://www.w3.org/WAI/ARIA/apg/patterns/grid/

[severo]

Also: see if we should get rid of the focus stop on the whole table (#135 (comment)).

Edit: No, it's useful to scroll the whole table. And the jump is fixed.

[severo]

For row selections, the recommendation (https://www.w3.org/WAI/ARIA/apg/patterns/grid/#datagridsforpresentingtabularinformation) is:

If a grid supports selection of cells, rows, or columns, the following keys are commonly used for these functions.

Control + Space: selects the column that contains the focus.
Shift + Space: Selects the row that contains the focus. If the grid includes a column with checkboxes for selecting rows, this key can serve as a shortcut for checking the box when focus is not on the checkbox.
Control + A: Selects all cells.
Shift + Right Arrow: Extends selection one cell to the right.
Shift + Left Arrow: Extends selection one cell to the left.
Shift + Down Arrow: Extends selection one cell down.
Shift + Up Arrow: Extends selection one cell up.

We don't want column selection for now, so I'll not implement it

[severo]

With respect to keyboard and rows selection, we need to:

• remove the current key bindings Space and Shift-space that scroll up and down (we will only support PageUp and PageDown for this) - remove ability to navigate with Space/Shift+Space #176
• if a selection exists, clicking any other part of the table, or moving the focus (navigating the table) should remove the selection no: it would prevent selecting non-successive rows.
• Space or Enter when a row header is focused: toggle the row selection - select/unselect with Enter or Space on checkbox #183
• Space or Enter when the table corner is focused: toggle all the rows - select/unselect with Enter or Space on checkbox #183
• Ctrl+A from anywhere: toggle all the rows - Keydown for toggle all and unselect #184
• Escape key from anywhere: exits the rows selection mode (ie: clear the selection) - Keydown for toggle all and unselect #184
• Shift+space: select the row of the focused cell (but keep the focus on that cell) - toggle row selection when Shift+space on a data cell #187
• Shift+space: if the row is already selected, remove the selection (even if multi rows) (and keep the focus on the current cell) - toggle row selection when Shift+space on a data cell #187
• when a selection exists, the focus is still held by a cell (not necessarily the row header with the checkbox) - the "anchor" field in selection should be the row index of the focused cell (maybe - note that the selection, including the anchor, can be controlled by the parent - maybe the anchor should be local state only?) - OK: the anchor is now updated to the last actioned row: toggle row selection when Shift+space on a data cell #187
• Shift+Up/Shift+Down if a selection exists: expand one row up/down from the current cell: no, it's for cells selection, not for rows selection
• Shift+PageUp/Shift+PageDown if a selection exists: expand one page of rows up/down from the current cell: no, it's for cells selection, not for rows selection
• Shift+Home/Shift+End, and Shift+Ctrl+Up/Down if a selection exists: expand to the first/last row from the current cell: no, it's for cells selection, not for rows selection

Other observations about the selection:

• use four icons, instead of a checkbox input, for the states: unselected, selected, unselected readonly, selected readonly -> not implemented yet, I created Replace decorative selection checkboxes with icons #188
• the checkbox is not vertically aligned in the 'row header' cells

[severo]

I think that #176, #183, #184 and #187 completes the issue by providing keyboard support for selecting the rows. Closing, but happy to get feedback @platypii and @bleakley.