be used here.  See |options|.  When using the local value
and there is no buffer-local or window-local value, the global value is used
anyway.


------------------------------------------------------------------------------
register						*expr-register* *@r*

@r			contents of register 'r'

The result is the contents of the named register, as a single string.
Newlines are inserted where required.  To get the contents of the unnamed
register use @" or @@.  See |registers| for an explanation of the available
registers.

When using the '=' register you get the expression itself, not what it
evaluates to.  Use |eval()| to evaluate it.


nesting							*expr-nesting* *E110*
-------
(expr1)			nested expression


------------------------------------------------------------------------------
environment variable					*expr-env*

$VAR			environment variable

The String value of any environment variable.  When it is not defined, the
result is an empty string.

The functions `getenv()` and `setenv()` can also be used and work for
environment variables with non-alphanumeric names.
The function `environ()` can be used to get a Dict with all environment
variables.


						*expr-env-expand*
Note that there is a difference between using $VAR directly and using
expand("$VAR").  Using it directly will only expand environment variables that
are known inside the current Vim session.  Using expand() will first try using
the environment variables known inside the current Vim session.  If that
fails, a shell will be used to expand the variable.  This can be slow, but it
does expand all variables that the shell knows about.  Example: >
	:echo $shell
	:echo expand("$shell")
The first one probably doesn't echo anything, the second echoes the $shell
variable (if your shell supports it).


------------------------------------------------------------------------------
internal variable					*expr-variable*

variable		internal variable
See below |internal-variables|.


------------------------------------------------------------------------------
function call		*expr-function* *E116* *E118* *E119* *E120*

function(expr1, ...)	function call
See below |functions|.


------------------------------------------------------------------------------
lambda expression				*expr-lambda* *lambda*

`{args -> expr1}`	lambda expression			*E451*

A lambda expression creates a new unnamed function which returns the result of
evaluating |expr1|.  Lambda expressions differ from |user-function|s in
the following ways:

1. The body of the lambda expression is an |expr1| and not a sequence of |Ex|
   commands.
2. The prefix "a:" should not be used for arguments.  E.g.: >
	:let F = {arg1, arg2 -> arg1 - arg2}
	:echo F(5, 2)
<	3

The arguments are optional.  Example: >
	:let F = {-> 'error function'}
	:echo F('ignored')
<	error function
							*closure*
Lambda expressions can access outer scope variables and arguments.  This is
often called a closure.  Example where "i" and "a:arg" are used in a lambda
while they already exist in the function scope.  They remain valid even after
the function returns: >
	:function Foo(arg)
	:  let i = 3
	:  return {x -> x + i - a:arg}
	:endfunction
	:let Bar = Foo(4)
	:echo Bar(6)
<	5
Note that the variables must exist in the outer scope before the lambda is
defined for this to work.  See also |:func-closure|.

Lambda and closure support can be checked with: >
	if has('lambda')

Examples for using a lambda expression with |sort()|, |map()| and |filter()|: >
	:echo map([1, 2, 3], {idx, val -> val + 1})
<	[2, 3, 4] >
	:echo sort([3,7,2,1,4], {a, b -> a - b})
<	[1, 2, 3, 4, 7]

The lambda expression is also useful for jobs and timers: >
	:let timer = timer_start(500,
			\ {-> execute("echo 'Handler called'", "")},
			\ {'repeat': 3})
<	Handler called
	Handler called
	Handler called

Note that it is possible to cause memory to be used and not freed if the
closure is referenced by the context it depends on: >
	function Function()
	   let x = 0
	   let F =