Vim

VIM

Vim (V IMproved) is a more featureful clone of the venerable UNIX text editor vi. It fucking rocks.

NOTE: the literal paste-job I've done here fucks with the alt and ctrl bindings, you'll most likely have to retype them yourself in vim (in insert mode press ctrl-v and then the keycombo (eg. alt-q)).

Highlighting long lines

Ever needed to make sure your lines fit on an 80-column line even though you prefer editing in a larger terminal? Here's some vimscript that when toggled with F2 will set the textwidth to 80 and highlight any characters that overflow the 80 character limit:

 " Global tracker var
 let g:HighlightLongLines = 0 "set to 0 so we can run it to enable
 " Function to toggle highlighting of lines longer than 80 character
 " It also toggles textwidth to 80 so newlines are forced when typing
 fu! ToggleHighlightLongLines()
       if(g:HighlightLongLines == 1)
               " Disable highlighting and textwidth
               highlight clear rightMargin
               set textwidth=0
               let g:HighlightLongLines = 0
       else
               " Enable highlighting and textwidth
               set textwidth=80
               highlight rightMargin ctermbg=LightRed guibg=LightRed
               match rightMargin /\%>81v/
               let g:HighlightLongLines = 1
       endif
 endfunction

 map <F2> :call ToggleHighlightLongLines()<CR>

Simple commenting script

All the vim commenting scripts I tried sucked and were like 400 lines of code. So, I made a very simple one:

 " try to detect and set the comment type
 autocmd BufRead,BufNewFile *.* call SetCommentType()

 vmap ^[q <Esc>:call VisualComment(line("'<"), line("'>"))<CR>
 nmap ^[q :call Comment(line('.'))<CR>

 function SetCommentType()
       " bail if no syntax type is defined
       if !exists('b:current_syntax')
               return
       end
       "hmm, this seems to be the only var we can use...
       let syn =  b:current_syntax
       "no switch statement, feh
       if syn == 'ruby'
               let b:comment_begin = '#'
       elseif syn == 'vim'
               let b:comment_begin = '"'
       elseif syn == 'c'
               let b:comment_begin = '/*'
               let b:comment_end = '*/'
       elseif syn == 'xml' || syn == 'html'
               let b:comment_begin = 
       " TODO - other languages
       else
               "Unhandled syntax
       end
 endfunction

 " (Un)Comment all selected lines
 function VisualComment(b, e)
       if !(exists('b:comment_begin'))
               return
       end
       "iterate over selected lines
       for i in range(a:b, a:e)
               call Comment(i)
       endfor
 endfunction

 " (Un)Comment out a line using the comment type defined for this syntax type
 function Comment(i)
       " comment details not defined...
       if !exists('b:comment_begin')
               return
       end

       " test for an empty line
       if match(getline(a:i), "^$") == 0
               return
       end
       if exists('b:comment_end')
               let comment_begin_esc = escape(b:comment_begin, '*')
               let comment_end_esc = escape(b:comment_end, '*')
               let regex = ('^\s*'.comment_begin_esc.'.\+'.comment_end_esc.'\s*$')
       else
               let comment_begin_esc = escape(b:comment_begin, '*')
               let regex = '^\s*'.comment_begin_esc.'.\+$'
       end

       let idx = match(getline(a:i), regex)

       if idx >= 0
               let newline = substitute(getline(a:i),  comment_begin_esc, , )
               if exists('b:comment_end')
                       let ridx = strridx(newline, comment_end_esc)
                       let part1 = strpart(newline, 0, ridx)
                       let part2 = strpart(newline, ridx)
                       let newline = part1.substitute(part2, comment_end_esc, , )
               end
               call setline(a:i, newline)
       else
               let newline = substitute(getline(a:i), '^', comment_begin_esc, )
               if exists('b:comment_end')
                       let newline = substitute(newline, '$', comment_end_esc, )
               end
               call setline(a:i, newline)
       end
 endfunction

NOTE: it should be trivial to add new comment types, just be aware that any special characters (like the * in the C mode) will need to be escaped. I was too lazy to add all the potentials to the escape() call but I couldn't think of any others that might be used in any comment system I'm familliar with anyway...

Editing mcrypted files with vim

Ever wanted to edit some files you've encrypted with mcrypt(1), but didn't want nasty unencrypted files lying around? With Vim and a little autocommands magic you can:

 " ###### LOADING ######
 autocmd BufReadPre,FileReadPre *.nc set bin "binary mode
 autocmd BufReadPre,FileReadPre *.nc set noshelltemp "force the use of pipes
 autocmd BufReadPre,FileReadPre *.nc set noswapfile "disable swapfiles
 "decrypt the file
 autocmd BufReadPost,FileReadPost *.nc '[,']!mcrypt -d
 autocmd BufReadPost,FileReadPost *.nc set nobin "turn off binary mode

 " ###### SAVING ######
 autocmd BufWritePre,FileWritePre *.nc set bin "binary mode
 "encrypt the data
 autocmd BufWritePre,FileWritePre *.nc '[,']!mcrypt
 "decrypt the buffer again
 autocmd BufWritePost,FileWritePost *.nc '[,']!mcrypt -d
 autocmd BufWritePost,FileWritePost *.nc set nobin "turn off binary
 "trigger a screen redraw cuz things are fucked up
 autocmd BufWritePost,FileWritePost *.nc normal ^L

NOTE: this may not be entirely secure, this is just something I pulled out of my ass while offline and browsing the vim documentation. It seems to work as desired, but you never know.

TODO: make the save part suck less (currently you need to type the passphrase *3* times, and vim gets all screwed up (hence the ctrl-l as the last step which forces a redraw). I'm not sure exactly how to do this though.

Resources

Vim.org - Vim's home page, lots of tips and scripts of sometimes dubious value. Vi-Improved.org - Contains example .vimrc and an excellent walkthrough of vim's features

--Andrew 22:44, 15 September 2006 (EDT)