Variable Scoping

So far Vimscript's variables may seem familiar if you come from a dynamic language like Python or Ruby. For the most part variables act like you would expect, but Vim adds a certain twist to variables: scoping.

Open two different files in separate splits, then go into one of them and run the following commands:

:let b:hello = "world"
:echo b:hello

As expected, Vim displays world. Now switch to the other buffer and run the echo command again:

:echo b:hello

This time Vim throws an error, saying it can't find the variable.

When we used b: in the variable name we told Vim that the variable hello should be local to the current buffer.

Vim has many different scopes for variables, but we need to learn a little more about Vimscript before we can take advantage of the rest. For now, just remember that when you see a variable that starts with a character and a colon that it's describing a scoped variable.

Exercises

Skim over the list of scopes in :help internal-variables. Don't worry if you don't know what some of them mean, just take a look and keep them in the back of your mind.