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VIM - Leader

vim allows a set of keys to be mapped as an alias to a different command in the ~/.vimrc file.

For example:

:nnoremap -d dd

NOTE: This maps that when -d is typed, it actually runs the dd command.

In this example,it would delete the current line.

Why not just map d to dd. Surely this would save typing a keystroke.

This could be dangerous, as just typing a single character could delete data.

As a safety precaution it is best to have to type this extra character.

But what if in future you want to change this prefix character?

One way is to manually modify each alias. Alternatively, use a leader.

Use a leader

:let mapleader = "-"

NOTE: Sets the leader to a hyphen.

:nnoremap <leader>d dd

NOTE: Defining the leader in one place makes it easy to change later.

Vim has a second “leader” key called local leader.

This is meant to be a prefix for mappings that only take effect for certain types of files, like Python files or HTML files.

:let maplocalleader = "\\"

NOTE:

\\ is used, and not just \ because \ is the escape character in Vimscript strings.

The <localleader> can be used just like <leader>.

:help mapleader
:help maplocalleader