Learn vimscript the hard way 01-10

Learn Vimscript the Hard Way

• vimscript excersize answer

Echoing Message

• instead of echo, echom will save the output and let you run :messages to view it later
  :echom "hello world"
:messages

fold example

Mapping

excersize

imap <c-u> <esc>gUiwA

nmap <c-u> gUiw

Strict mapping

:nmap - dd
:nmap \ -

• Vim will take other mapping : Pure evil

Recurlsion

:nmap dd O<esc>jddk

• it looks like clear the line but...
• It calls the new dd(mapping to clear previous line) again and again and again...

Side effect

• Danger of recursing
• Mapping key of plugin

Nonrecursive mapping

• Each *map has *noremap

  nmap x dd
  nnoremap / x

When should you use these nonrecursive variants instead of their normal counterparts?
Always.
No, seriously, always.

Leaders

• What if we need the mapping key later?
• Vim doesn't use H, L, -, <space>, <bs>, <cr>: Only six

Mapping key sequences

• Easy to map more then just single key

  nnoremap -d dd
  nnoremap -c ddO

• Vim had mechanism for this "prefix" key
• Vim called this prefix key the "leader"

Leader

:let mapleader = "-"

• You can replace - with any key you like
• I personally like ,
• Then you can use leader like below

nnoremap <leader>d dd

• Why don't use - directly instead of <leader>?
  • 1. Can change leader later easily
  • 2. Share easily
  • 3. Many plugins create mappings based on leader

Local leader

• is to be used for mappings which are local to a buffer

:let maplocalleader = "\\"

Editing your VIMRC

The idea of this chapter is that you want to make it easier to make it easier to edit text.

:nnoremap <leader>ev :vsplit $MYVIMRC<cr>

• $MYVIMRC: special variable that points your vimrc file
• Personally, I use global mark V so that I can open vimrc file by \V`

Sourcing mappings

• Once add config in ~/.vimrc, it doesn't immediately take effect
• like so % or source ~/.vimrc
• Let's make it easier

nnoremap <leader>sv :source $MYVIMRC<cr>

Abbreviations

:abbrev adn and

• Will automatically chagne adn to and

Keyword Characters

• Vim will substitute an abbreviation when you type any "non-keyword character" after an abbreviation
• "non-keyword character" means any character not in the iskeyword option.

  :set iskeyword?
  iskeyword=@,48-57,_,192-255

• it means all ASCII characters, digits, underscore, and so on

More Abbreviations

• Abbreviations are useful for more than just correcting typos

:iabbrev @@    steve@stevelosh.com
:iabbrev ccopy Copyright 2013 Steve Losh, all rights reserved.

Why Not Use Mappings?

:inoremap ssig -- <cr>Steve Losh<cr>steve@stevelosh.com

• if type Larry Lessig wrote the book "Remix". after mapping, vim expand ssig into name
• Mapping don't take into account what characters come before or after the map

:iunmap ssig
:iabbrev ssig -- <cr>Steve Losh<cr>steve@stevelosh.com

More Mappings

• Can mapping in sequence of multiple keys

  :nnoremap jk dd

A more complicated mapping

:nnoremap <leader>" viw<esc>a"<esc>bi"<esc>lel

Exercises

• Use vnoremap to quote whatever inside visually selected

  :vnoremap <leader>" <esc>`>a"<esc>`<i"<esc>

• Map H in normal mode to go to the end of the current line.

• Originally, H is mapping to line from top of window. :help H

  :nnoremap H 0

• Map L in normal mode to go to the end of the current line.

• Originally, H is mapping to line from bottom of window. :help L

  M is mapping to middle of window.

  :nnoremap L $

Training your fingers

:inoremap jk <esc>

• Many ways to exit insert mode by default

<esc>
<c-c>
<c-[>

• Using jk is great becasue the keys are right under two of your strongest fingers
• What about if you write in a language where jk ? Change to different mapping (...)

Learning the Map

• To excersize new mapping above, you can force yourself to use it by disabling(!) the old key (lol)

:inoremap <esc> <nop>

• <nop> means no operations