What does "Blockwise" in execute mode do?

Question

I have the following in a .vimrc file:

vmap ; :Blockwise<SPACE>

I'm not sure what the Blockwise key word does.

Answer 1

It's an Ex command, and since its first character is written in uppercase, it's probably a custom command.

To see what it does, and where it was defined, you can use this command:

:verbose command Blockwise

… or shorter:

:verb com Blockwise

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By default, an Ex command operates on whole lines.

So, for example, suppose you wanted to perform a substitution inside a column in a paragraph. You could visually select it, then type :s/pattern/replacement/g. You could think that the substitution command would replace the occurrences of pattern with replacement only inside the block, but since Ex commands operates on whole lines, :s would replace pattern anywhere in the paragraph, not just inside the column you selected.

As a workaround, inside the pattern, you could use the atom \%V (see :h /\%V), but it may not be always as simple for other commands (other than :s).

With your mapping, if you hit ; in visual mode, Vim will write on the command line :'<,'>Blockwise.

So, it's just a guess, but your :Blockwise command probably expects as an argument another command, and limits the effect of the latter on a visual blockwise selection. It may be a mechanism to enable all or most of Vim Ex commands to operate on blockwise selection, and not just whole lines.

With it, you could probably do something like:

:'<,'>Blockwise s/pattern/replacement/g

… to replace pattern with replacement, only inside the visual block.

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When you find the name of a command which you don't know, you can try to look for it inside the help, with the :helpgrep or :lhelpgrep command. The latter can be shortened into :lh. Currently, if I type:

:lh :Blockwise

I don't have any results, so with this you would know it's not a default Vim command. However, if it has been installed with a plugin which has some documentation, then it's possible that the previous command returns some results.

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You probably want to replace :vmap, with :xnoremap. In front of a :map command, v doesn't mean visual mode, it means visual mode+select mode. x stands for visual mode only. So, if you use :vmap, you will bind a printable character (;) in select mode. And the help says that it could be confusing to a user (:h mapmode-x):

NOTE: Mapping a printable character in Select mode may confuse the user.

You could change your mapping like this:

xnoremap ; :Blockwise<Space>