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How to make a keymap

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Tip 619 Printable Monobook Previous Next

created December 14, 2003 · complexity basic · author Tony Mechelynck · version 6.0


This tip explains how to make a keymap for yourself. It is based on:

You'll also find relevant information at:

How to name the file and where to place it

Keymaps reside in the "keymap" subdirectory of the directories named in 'runtimepath'. Their names are of one of the forms:

<keymap>.vim
<keymap>_<encoding>.vim

so if you need keymaps for Czech and Norwegian, and want to use them under UTF-8, you will probably create two keymaps, named, for instance, "czech_utf8.vim" and "norwegian_utf8.vim". If those names collide with names already present in $VIMRUNTIME/keymap/, then either use slightly different names before the underline, or put them in the "keymap" subdirectory of a directory named earlier than $VIMRUNTIME in 'runtimepath', so yours will be found first (but in the latter case you won't be able to use the default keymap of the same name). Create the needed directory if it doesn't exist yet.

What a keymap consists of

A keymap consists of three parts:

  1. a Vim script
  2. a line containing only the word "loadkeymap" (without quotes)
  3. the key mappings themselves.

First part of a keymap: the Vim script

This may contain any Ex-commands and Vim comments germane to the use of the keymap. In particular, the following Ex-commands are useful:

(1) If this keymap is only a slight modification of another, preexisting one: a "source" statement for the keymap on which this one is based. Then you will only have to code the changes.

(2) A short name, for instance in a keymap for Czech

let b:keymap_name="cz"

This will appear as <cz> near the right end of the standard status line for any window where the keymap in question is enabled (by having its long name set ot setlocal'ed in 'keymap' and 'iminsert' setlocal'ed to 1).

(3) A cursor color for when keymaps are in use. This one is more controversial (Bram comments it out in published keymaps) but I find it useful in my "private" ones.

highlight lCursor ctermbg=red guibg=red

Use any color that pleases you, and beware that highlight groups are global for the whole of Vim, so it is possible to use different keymaps in split windows of a single Vim instance, but not different language cursor colors, unless you set up an autocommand to change the lCursor highlight at the WinEnter event. (How to make that work is outside the scope of this HowTo.)

Second part: the loadkeymap command

This is just to tell Vim that whatever comes after, to the end of the file, is a series of language-mappings, in a special format which will be described hereafter.

Third part: The mappings themselves

Each key mapping line consists of three parts; the optional third one may contain spaces but not the first two:

{lhs} {rhs} [comment]

Vim interprets this line as if (in a standard Vim script) there had been

lmap <buffer> {lhs} {rhs}

The {lhs} is what you press, as interpreted by your default (English) keyboard. It is usually a single character, but it may be more than one: in that case all of them but the last act as "dead keys". For instance, in a German keymap, you may want to use the colon as a prefix to tell that the following vowel gets an umlaut (so that :A maps to Ä, :a to ä etc.)

Any key or key combination which does not appear as an {lhs} keeps its "English" meaning in the target language. (This will usually be the case for the space bar and for any punctuation, or even letters, that you don't want to move about on the keyboard.) This means that if, for instance, you map the sz letter pair to the German eszet, you'll still be able to use the small-s letter with its usual meaning whenever it is not followed by z. Similarly, if you map the colon as above, a colon remains a colon if followed by anything other than a vowel, for instance a space or a digit.

In all cases, you can force the initial key(s) of a mapping to keep their original meaning, either by waiting for the mapping to time out, or by moving the cursor about, for instance with <Left><Right>.

The {rhs} is what it translates to, in the target language. For UTF-8 the {rhs} may be of the form <Char-0> to <Char-2347483647> (decimal), or <Char-0x0> to <Char-0x7FFFFFFF> (hex), or <Char-00> to <Char-017777777777> (octal) -- see :help <Char>. For other encoding targets, the <Char> notation may also be used, but of course only as far as the target permits: e.g. in 8-bit encodings, only till 255 / 0xFF / 0377.

The [comment] is the easiest: it's for the human reader of the keymap, not for Vim.

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