Vim 9.0 released
After many years of gradual improvement Vim now takes a big step with a major
release. Besides many small additions the spotlight is on a new incarnation of
the Vim script language: Vim9 script.
The previous release was version 8.2 in December 2019. Since the latest
source code is always available on GitHub, many have already picked up later
patch versions (there are more than 5000 of them!). Therefore the changes have
already been tried out by many users. On top of that bugs have been fixed,
security issues have been addressed, and many tests have been added. Code
coverage has been dramatically increased. This version is more reliable than
Why Vim9 Script
A new script language, what is that needed for? Vim script has been growing
over time, while preserving backwards compatibility. That means bad choices
from the past often can't be changed and compatibility with Vi restricts
possible solutions. Execution is quite slow, each line is parsed every time it
The main goal of Vim9 script is to drastically improve performance. This is
accomplished by compiling commands into instructions that can be efficiently
executed. An increase in execution speed of 10 to 100 times can be expected.
A secondary goal is to avoid Vim-specific constructs and get closer to
The performance improvements can only be achieved by not being 100% backwards
compatible. For example, making function arguments available by creating
an "a:" dictionary involves quite a lot of overhead. In a Vim9 function this
dictionary is not available. Other differences are more subtle, such as how
errors are handled.
For those with a large collection of legacy scripts: Not to worry! They will
keep working as before. There are no plans to drop support for legacy script. No drama like with the deprecation of Python 2.
To profit from the speedup a function must be defined with def
The argument and return types must be specified. This is not only to make
execution faster, it also helps uncovering mistakes early, when the function is
compiled into byte code. Variables are declared with var
and also have
a type, either explicitly or inferred from the assigned value.
Line continuation does not require using a backslash, the mechanism that is
used in legacy script, which is a bit weird and was required to keep it
Function calls do not require call, assignments are done without
let and expressions are evaluated without eval. This makes a
Vim9 script look a lot more like most programming languages.
Splitting up a large script in small pieces has been made a lot simpler. In
one script export is used to make specific functions and variables
available to other scripts. The rest is local to the script. Then
import is used where the exported items are to be used. Combined with
an autoload mechanism this makes a flexible and powerful way to implement large
Comments now start with #. The previous double quote syntax, which
comes from the good old Vi, interferes with how strings are used. The use of
# is known from many other languages, such as Python and shell scripts.
Otherwise most things work the same way. Users who have written Vim script
will find it easy to switch over. Unexpected differences usually lead to an
error message with a hint how to do make the line work in Vim9 script.
Details about Vim9 script and rationale for the choices can be found
or with :help vim9 in Vim.
Otherwise, many improvements were made not related to Vim9 script. You can
find a list here or
with :help new-9 in Vim.
There will surely be a Vim 9.1 release. Nobody knows when.
Among the plans for Vim9 script is the addition of classes. Although a
dictionary can be used to simulate this, it is far from ideal. Most
programmers are familiar with classes such as Java has. Something like that
should be added to Vim9 script. The keywords are already reserved.
Vim is a highly configurable text editor built to make creating and changing
any kind of text very efficient. It is included as "vi" with most UNIX systems
and with Apple's macOS.
Much of Vim was written by Bram Moolenaar (Bram@Vim.org). Many, many others
have helped making Vim what it is now by adding features, fixing bugs,
suggesting improvements, etc.
Vim is Charityware. You can use and copy it as much as you like, but you are
encouraged to make a donation for needy children in Uganda. Please
visit the ICCF web site for more information: