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File: Backup.FPL
Author: Daniel Stenberg
Email: dast@sth.frontec.se, FidoNet 2:201/328
Short description: Make backups at save-time
Version: 1.0
Date: 22.4.94
Local settings: "backup" ("_backup" is hidden)
Global settings: "backup_suffix"
Keysequence:
Type: Hook
Prereq:
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FUNCTION

  The reason for this program is to save us all from the following scenario:
You load a file, modify and save it and then quits. You try to compile the
new file and after the compiler has discovered the 47 errors in the file,
you get second thoughts about the latest modification and want to get back the
previous version of the file.

  This program hooks Save() and performs a safety copy of the file that is to
be overwritten by the save operation. The backup is only performed at the
first save of the file, at not at any later time during the editing session.

  The backup file will get a suffix that defaults to ".bak" (changeable
through the "backup_suffix" global setting). If the backup file already exists
when the backup copy is about to perform, a requester will appear propting if
the file should be overwritten or not. Whether the answer is true or false,
the operation will be marked internally as if the backup has been done!

  The backup option is switchable on/off with the local boolean setting called
"backup".

BUGS

  I use the AmigaDOS command "list" to check whether the backup file already
exist or not. Even with the stdout redirected to NIL: some error text will be
generated to stderr (not redirectable!) when the backup file is absent.