diff options
Diffstat (limited to 'runtime/doc/undo.txt')
| -rw-r--r-- | runtime/doc/undo.txt | 26 |
1 files changed, 22 insertions, 4 deletions
diff --git a/runtime/doc/undo.txt b/runtime/doc/undo.txt index 36b2ff9e4e..3fcc196250 100644 --- a/runtime/doc/undo.txt +++ b/runtime/doc/undo.txt @@ -114,7 +114,17 @@ use CTRL-G u. This is useful if you want an insert command to be undoable in parts. E.g., for each sentence. |i_CTRL-G_u| Setting the value of 'undolevels' also closes the undo block. Even when the -new value is equal to the old value: > +new value is equal to the old value. Use `g:undolevels` to explicitly read +and write only the global value of 'undolevels'. > + let &g:undolevels = &g:undolevels + +Note that the similar-looking assignment `let &undolevels=&undolevels` does not +preserve the global option value of 'undolevels' in the event that the local +option has been set to a different value. For example: > + " Start with different global and local values for 'undolevels'. + let &g:undolevels = 1000 + let &l:undolevels = 2000 + " This assignment changes the global option to 2000: let &undolevels = &undolevels ============================================================================== @@ -351,12 +361,20 @@ undo is possible. Use this if you are running out of memory. When you set 'undolevels' to -1 the undo information is not immediately cleared, this happens at the next change. To force clearing the undo information you can use these commands: > - :let old_undolevels = &undolevels - :set undolevels=-1 + :let old_undolevels = &l:undolevels + :setlocal undolevels=-1 :exe "normal a \<BS>\<Esc>" - :let &undolevels = old_undolevels + :let &l:undolevels = old_undolevels :unlet old_undolevels +Note use of `&l:undolevels` to explicitly read the local value of 'undolevels' +and the use of `:setlocal` to change only the local option (which takes +precedence over the corresponding global option value). Saving the option value +via the use of `&undolevels` is unpredictable; it reads either the local value +(if one has been set) or the global value (otherwise). Also, if a local value +has been set, changing the option via `:set undolevels` will change both the +global and local values, requiring extra work to save and restore both values. + Marks for the buffer ('a to 'z) are also saved and restored, together with the text. |