The Vi editor, though several decades old now, is still one of the most popular tools for programmers, especially those using Unix-family systems (Linux, Mac). It includes the basics such as programming language-specific syntax coloring, autoindent, autocomplete, interface with compilers and debuggers and so on. In addition, numerous plugins are available; for example, if one is editing Python code, one can issue a command to move the cursor to the beginning or end of the current block. GVim, a GUI version of Vim, is also popular.
I personally use Vim because I want to use the same editor no matter whether I am writing code, writing a research paper, writing e-mail etc. I've developed my own abbreviations and macros to make typing easier for myself. In my ~/.vimrc Vim startup file, for example, I have a line
abb for example for example
so that whenever I type 'frre', Vim automatially expands it to "for example". I'm writing this Web page using Vim, and I wrote the Python examples using that editor too.
It is assumed that the reader knows very basic Vim operations, such as in this brief tutorial. In particular you must know that Vim has insert (adding text) and noninsert (deleting text, cursor movement, file saving etc.) modes. In noninsert mode, the : key is used to get into special command mode, such as to invoke Python.
Vim is extraordinarily configurable, using its own built-in scripting language, Vimscript. However, Vimscript is rather tedious and confining. Fortunately, Vim is actually programmable in Python!
into a terminal window to make sure your version of Vim was configured with Python.
:py import vim
(or you can write the Python code itself to this).
:py print "hello world"
from within a Vim session, and sure enough, "hello world" appears in the status line at the bottom of the screen.
from within that session. That file will actually be considered to be Vimscript code, but with Python embedded.
:map hw :py print "hello world"
in x. From then on, whenever you type 'hw' in noninsert mode, you'll see the greeting appear in the status line.
python << endpy import vim lines of Python code endpy Vimscript line to call the Python code
This example is from the excellent tutorial by soulseekah. With this, if you are using Vim to edit a file that contains IP addresses, you simply type '.IP' and it will inform you the country in which that address is located.
" from " " http://codeseekah.com/2012/03/04/vim-scripting-with-python-lookup-ip-country/ python << en import vim, urllib def getCountryFromIP( ip ): # use the minimal http://www.hostip.info/use.html API return urllib.urlopen('http://api.hostip.info/country.php?ip='+ip).read() def getWordUnderCursor(): return vim.eval("expand('
')") def lookupIPUnderCursor(): ip = getWordUnderCursor() print "Looking up " + ip + "..." country = getCountryFromIP( ip ) vim.command( "redraw" ) # discard previous messages print "Country: " + country en nmap .IP :python lookupIPUnderCursor()
Things should be fairly clear from context (don't worry if you are not familiar with the Python urllib module), but a few items need explanation:
Create a file, y, with exactly the following famous contents:
How much wood, Would a woodchuck chunk, If a woodchuck Could chuck wood?
Now, with this file open in Vim, type
:py b = vim.buffers
Vim allows one to have several buffers at once, i.e. to edit several files at once. A command like
means "switch to buffer 2." (In GVim, the GUI version of Vim, this is done by mouse.) The above Python command copies the contents of buffer 1 to the Python variable b. Now b is a Python list (i.e. array), with character-string elements, one element per line of y.
:py print b
i.e. print the fourth line of the file,
(Remember, Python array indices start at 0, not 1.)
:py b = ''
But Vim has infinite-undo capability, invoked with the u command (ctrl-r for re-do). You can do that through Python too:
It would be pointless to do this with Python in this little example, but the point is that one can do things like this programmatically -- and using a nice language, Python, to do it.