Reverse a word in Vim

Question

How can I reverse a word in Vim? Preferably with a regex or normal-mode commands, but other methods are welcome too:

word => drow

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Answer 1

There is a tricky way to do this if you have Vim compiled with +rightleft. You set 'allowrevins' which let you hit Ctrl+_ in insert mode to start Reverse Insert mode. It was originally made for inserting bidirectional scripts.

Type your desired word in Insert mode, or move your cursor to the end of an already typed word. Hit Ctrl+_ and then pick a completion (i_Ctrl-x) method which is the most likely not to return any results for your word. Ysing Ctrl+e to cancel in-place completion does not seem to work in this case.

I.e. for an unsyntactic text file you can hit in insert mode Ctrl+x Ctrl+d which is guaranteed to fail to find any macro/function names in the current file (See :h i_CTRL-X_CTRL-D and:h complete for more information).

And voila! Completion lookup in reverse mode makes the looked up word reverse. Notice that the cursor will move to the beginning of that word (it's reversed direction of writing, remember?)

You should then hit Ctrl+_ again to get back to regular insert mode and keyboard layout and go on with editing.

Tip: You can set 'complete' exclusively (for the buffer, at least) to a completion option that is guaranteed to return no result. Just go over the options in :h 'complete'. This will make the easy i_Ctrl-N / i_Ctrl-P bindings available for a handy word reversal session. You can ofcourse further automate this with a macro, a function or a binding

Note: Setting/resetting 'paste' and 'compatible' can set/reset 'allowrevins'. See :h allowrevins.