The Character Delete Buffer

The character delete buffer is arranged as a stack 256 characters long. Adding a character to a full buffer will cause the oldest character to be lost. In this manner the most recent 256 characters are kept.

The editor maintains primitive commands for:

• adding a character to the buffer.
• removing the last character which was added to the buffer.
• purging the buffer.

These primitives are provided by subcommands of the Zap (z) command.

The saving of the last deleted character via the Del key is performed by a macro which saves the character under the cursor in the character delete buffer before deleting it. Likewise, the restoration of a deleted character via the Ctrl–Ins key combination is based upon a macro which inserts the last character placed in the delete buffer before the current cursor position.