Suggestion: Improve syntax of "if not exist"

Related StackOverflow Q/A: http://stackoverflow.com/a/31888581/450913

The syntax of Test-Path in conditional statements is unnecessarily verbose (specially in the negated case), and prone to logical errors if parenthesis are not used properly:

if (Test-Path $path) { ... }
if ($path | Test-Path) { ... }

if (-not (Test-Path $path)) { ... }
if (-not ($path | Test-Path)) { ... }
if (!(Test-Path $path)) { ... }
if (!($path | Test-Path)) { ... }

I would like to suggest the following aliases to be supported natively in PowerShell:

function not-exist { -not (Test-Path $args) }
Set-Alias !exist not-exist -Option "Constant, AllScope"
Set-Alias exist Test-Path -Option "Constant, AllScope"

With that, the conditional statements will change to:

if (exist $path) { ... }

and

if (not-exist $path) { ... }
if (!exist $path) { ... }

Much more readable and avoids logical errors that happen in statements such as: if (-not $path | Test-Path) { ... }

Another idea is to implement them natively as “-Exist” and “-NotExist” operators.

Also as suggested by Derp McDerp in UserVoice item:

An alternative way of fixing this is for powershell to alter the grammar to allow the following syntax sugar:

if !(expr) { statements* } 
if -not (expr) { statements* }

[rkeithhill]

if !(expr) { statements* } if -not (expr) { statements* }

I like Derp’s idea at first blush. It would apply to many more cases than just Test-Path.

[IISResetMe]

if -not (expr) { ... } would indeed be consistent with the switch statement grammar.

An alternative would be to introduce a negated if statement like perl’s unless:

unless (expr) { ... } else { ... }