The History

1. Description
   CoCoA's Interactive Document maintains a history of all executed command sets. This history can be browsed and - to a limited extent - edited.

   Entering a command set in the Interactive Document and executing it using Ctrl + Return triggers the following actions:

   - The command set is appended to the history of the Interactive Document.
   - The Interactive Document jumps to the end of its history thus displaying (most of the time - see below) an empty page.
   - The command set is executed.

   Thus you can imagine the history in the following way

   where the rectangle with the arrows represents the history cursor, i.e. the current position the history. The history cursor can be moved using the keys Alt + Left (to go to a command set entered earlier) and Alt + Right (to go to a command set entered later). When the history cursor is positioned on the last history page and you press Alt + Right a new empty page will be opened.
   The current position of the history cursor is shown in the HI status bar entry when the Interactive Document is active.

   Since there might be situations when you don't want all of the three actions mentioned above to be executed, there are several key combinations to change that behaviour:

   - Pressing Alt + Return instead of Ctrl + Return does the same as Ctrl + Return except that it does not trigger execution of the command set.
   - Pressing Shift together with Ctrl + Return or Alt + Return prevents the jump to the end of the history. This is useful, when you are editing a command set and executing it from time to time to see whether it works or not.
   - Pressing Shift + Return alone replaces the current history page and does not execute the command set.
   Apart from that, you can use Ctrl + Delete to remove the page you are currently editing from the history.

   When you are not in the Interactive Document, all of the above key combinations should work except the combinations to browse the history and the key combination Shift + Return to replace the current history page and Ctrl + Delete to remove the current history page, since those make no sense when you are not in the Interactive Document.

2. Shortcuts

   Key | Modifiers | Description
   --- | --- | ---
   | Alt | Ctrl | Shift |
   Return | - | X | - | Append, Execute, Jump
   Return | X | - | - | Append, NoExecute, Jump
   Return | - | - | X | Replace, NoExecute, NoJump
   Return | X | - | X | Append, NoExecute, NoJump
   Return | - | X | X | Append, Execute, NoJump
   Left | X | - | - | Previous interactive page
   Right | X | - | - | Next interactive page
   Delete | - | X | - | Delete current history page