96cf3ead3c63
ftdetect
| author | Steve Losh <steve@stevelosh.com> |
|---|---|
| date | Sun, 13 Nov 2011 19:12:41 -0500 |
| parents | 17fbafb16c45 |
| children | 9a3df9479748 |
| branches/tags | (none) |
| files | chapters/44.markdown outline.org |
Changes
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/chapters/44.markdown Sun Nov 13 19:12:41 2011 -0500 @@ -0,0 +1,76 @@ +Detecting Filetypes +=================== + +Let's create a Potion file we can use as a sample as we're working on our +plugin. Create a `factorial.pn` file somewhere and put the following Potion +code inside it: + + factorial = (n): + total = 1 + n to 1 (i): + total *= i. + total. + + 10 times (i): + i string print + '! is: ' print + factorial (i) string print + "\n" print. + +This code creates a simple factorial function and calls it ten times, printing +the results each time. Go ahead and run it with `potion factorial.pn`. The +output should look like this: + + 0! is: 0 + 1! is: 1 + 2! is: 2 + 3! is: 6 + 4! is: 24 + 5! is: 120 + 6! is: 720 + 7! is: 5040 + 8! is: 40320 + 9! is: 362880 + +Detecting Potion Files +---------------------- + +Open `factorial.pn` in Vim and run the following command: + + :set filetype? + +Vim will display `filetype=` because it doesn't know what a `.pn` file is yet. +Let's fix that. + +Create `ftdetect/potion.vim` in your plugin's repo. Put the following lines +into it: + + augroup potion_detect + au! + au BufNewFile,BufRead *.pn set filetype=potion + augroup END + +This creates an autocommand group with one autocommand inside: a command to set +the filetype of `.pn` files to `potion`. Pretty straightforward. + +Close the `factorial.pn` file and reopen it. Now run the previous command +again: + + :set filetype? + +This time Vim displays `filetype=potion`. When Vim started up it loaded the +autocommand group inside `~/.vim/bundle/potion.vim`, and when it opened +`factorial.pn` the autocommand fired, setting the `filetype` to `potion`. + +Now that we've taught Vim to recognize Potion files we can move on to actually +creating some useful behavior in our plugin. + +Exercises +--------- + +Read `:help ft`. Don't worry if you don't understand everything there. + +Read `:help setfiletype`. + +Modify the Potion plugin's `ftdetect/potion.vim` script to use `setfiletype` +instead of `set filetype`.