Vim9script
See also Vimscript, which is the original language predating Vim 9.
Example
This is a convoluted example, making use of a command that is also compatible with traditional Vimscript, but nonetheless works.
The Vim9script interpretter only begins to run after the vim9script command is seen within a script.
vim9script :echo "Hello, world!"
Breaking Changes
The comment character has been changed from a doublequote (") to a hash (#)
- White space is required in many places to improve readability.
Declare variables with :var
- Variables are script-local by default
Assigning values to variables does not require :let
Declare constants with :final and :const Constants can be declared with :final and :const:
:final cannot be used as a short form of :finally
Declare functions like def CallMe(count: number, message: string): bool
- Functions are script-local by default
Calling functions does not require :call
Many ex(1) commands have been removed
:Print
:append
:change
:d immediately followed by d or p.
:insert
:k
:mode
:open
:s followed only by flags
:t
:xit
Many commands cannot be shortened (see vim9-no-shorten)
- Curly brace names are disallowed
A range before a command must be prefixed with a colon (e.g. :%s/foo/bar)
Executing a register requires prefixing with a colon (e.g. :@r) or using :exe (e.g. :exe @r)
- Expression mappings are evaluated in the context of its definition
Furthermore, in order to break code across lines in traditional Vimscript, backslashes were often necessary. Vim9script does not have the same requirement.
Functions are now compiled. The compilation occurs in the background of a vim(1) session, and may raise errors.
Variables and Constants
var count = 0 count += 3
final matches = [] # add to the list later const names = ['Betty', 'Peter'] # cannot be changed
Functions
Vim9script tries to compile functions lazily. Compilation is triggered by:
- the first call to a function
a :defcompile command located within a script after the function definition
:disassemble
- a new function definition that calls to a function, or uses a function as a function reference
To forward reference a function that is not defined yet, try:
def MyFunc()
execute('DefinedLater')
enddef