Merge branch 'PR/3' into useful-vim-features

content/posts/useful-vim-features.md

@@ -205,6 +205,70 @@ find that color really helps my brain process large chunks of text (whether
 that's just how my brain works or it's how it has changed after years of using
 syntax highlighting, I'm unsure).
 
+# Insert Mode Completions
+
+Did you know that Vim has its own completion system that you can invoke from
+Insert mode?  I don't know how many people know about this functionality, but
+I've found it invaluable in saving myself keystrokes and time!
+
+You enter into completion mode via `Ctrl-x`, and from there you enter Ctrl plus
+another key to select which mode of completion you want.  There are quite a few
+modes - here are the ones I find myself using most often:
+
+## `Ctrl-X Ctrl-N`: Keywords in `complete`
+
+This has two convenient shortcut in the forms of `Ctrl-N` and `Ctrl-P`, which
+select the next and previous found keywords, respectively.  "Found" here is
+defined by the 'complete' option, which you can set to have the completion
+search the current buffer, all open buffers, `tags` files, and much, much more
+- check out `:help 'complete'` for a full listing!
+
+I use this most often to complete variable or function names that I've typed
+already, but are long enough to be annoying to type, or contain certain
+character combinations that I find difficult to type.
+
+## `Ctrl-X Ctrl-F`: Filename completion
+
+I use this one _all_ the time!  If you're typing a path to a file, you can
+generate completions for that path while you're typing it.
+
+## `Ctrl-X Ctrl-K`: Dictionary completion
+
+I use this one occasionally when writing prose - it does exactly what it says!
+It's handy for completing long words like "respectively" - my only complaint
+about it is that it presents _way_ too many results by default, and they're
+ordered alphabetically, rather than by something like general frequency or
+frequency in the current context.  The "too many results" problem could
+probably be rectified by using a different dictionary for completions, but the
+ordering problem would probably require a plugin of some sort.
+
+## `Ctrl-X Ctrl-L`: Whole line completion
+
+I admit - when I first read about this mode, I thought to myself "who would
+ever use that?" - and now I find myself using it way more than I thought I
+would!  I think I mostly use it when writing YAML for Kubernetes manifests -
+like if I have a complete manifest open in another buffer and I want to
+complete `apiVersion: ` or something.  It's also handy for copying a line
+currently on your screen - let's say you want to copy a line 17 lines above the
+cursor.  You _could_ do `<escape> 17k yy 17j p`, or `:-17t .`, but I've found
+it's quick and easy to type a short prefix and then use `Ctrl-X Ctrl-L`.
+
+## `Ctrl-X Ctrl-O`: Omni-completion
+
+I saved the most flexible one for last - omni-completion!  Omni-completion is
+Vim's term for one of its forms of user-customizable completion - you'll most
+often see it used for things like language-aware completions.  For example, if
+you're writing Go and you're using one of the Go support plugins, or if you're
+using a plugin that hooks into the Language Server Protocol, using `Ctrl-X
+Ctrl-O` will tell Vim to ask for completions for things like "what variables
+are currently in scope?" or "what methods are present on this variable?".
+
+## Other modes
+
+I've only the few modes that I've actually used in practice - there a quite a
+few more, so I suggest checking out `:help ins-completion` to see if any of the
+others listed there give you ideas for improving your Vim workflow!
+
 ---
 
 This article was a collaboration between [Neil Bowers](), [Rob Hoelz](https://hoelz.ro),