Undo operations

In this section:

• %N.Meb[options]
• Standard call-back functions
• Colouring the text and background
• Text search
• Text search/replace
• Buffer positioning
• Undo operations
• Opening a file
• Inserting text
• Moving around the display
• Deleting text
• Marking blocks
• New CLEARWIN_INFO@ parameters
• Clipboard cut/paste
• Scroll position

SUBROUTINE UNDO_EDIT_CHANGE@(E)
INTEGER E(24) ! EDIT_INFO block

Performs one level of undo operation. A single undo may reverse the effects of several function calls. Direct user interactions with the edit box are tagged so that one user command is reversed at each step (even though it may be implemented in several steps). Other operations should be tagged as required using NEXT_EDIT_OPERATION@ described next.

SUBROUTINE NEXT_EDIT_OPERATION@(E)
INTEGER E(24) ! EDIT_INFO block

Calling this function indicates to the edit box that future changes are to be considered to belong to a new user operation. Typically you would call this routine at the head of a menu call-back function that was about to change the edit buffer in some way. If you perform a long series of changes without calling this function, they will all be reversed as a block if the user performs an undo operation.

Alternatively you can pass the window handle instead of the EDIT_INFO.

See also: EDIT_INFO