Microsoft® JScript™ @set Statement | Language Reference Version 3

See Also

##### Description

> Allows creation of variables used in conditional compilation statements.

##### Syntax

> @set @varname = term

> The @set statement syntax has these parts:

> Part | Description
> varname | Valid JScript variable name. Must be preceded by an "@" character at all times.
> term | Zero or more unary operators followed by a constant, conditional compilation variable, or parenthesized expression.

##### Remarks

> Numeric and Boolean variables are supported for conditional compilation. Strings are not. Variables created using @set are generally used in conditional compilation statements, but can be used anywhere in JScript code.

> Examples of variable declarations look like this:

> >     @set @myvar1 = 12
> >     @set @myvar2 = (@myvar1 * 20)
> >     @set @myvar3 = @_jscript_version

The following operators are supported in parenthesized expressions:

- ! ~
- * / %
- + -
- << >> >>>
- < <= > >=
- == != === !==
- & ^ |
- && ||

If a variable is used before it has been defined, its value is NaN. NaN can be checked for using the @if statement:

>     @if (@newVar != @newVar)
>       ...

This works because NaN is the only value not equal to itself.

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