& is the retarget symbol. It allows multiple member tags to be called in succession on a single base type. The individual member tag calls are separated by the ampersand. Each tag call is applied to the base type in order.

For example, this expression [$string->Reverse & Uppercase] performs the [String->Reverse] tag on the string followed by the [String->Uppercase] tag. The result is a string that has been both reversed and converted to uppercase.

The retarget symbol can also be used to return the value for the base type after a member tag call. The retarget symbol is specified after the member tag.

For example, this expression [$string->Reverse &] will reverse a string, modifying the $string variable in place, and return the value of the reversed string. This allows a string to be modified and the result to be used immediately.

Note: Some member tags do not work on literal values. for example, the expression ['string'->Reverse &] will not work since the string literal cannot be modified. In this case it is preferable to store the string in a variable or to use substitution tags.

[Instance->(Tag: Params) & (Tag: Params)]

[Instance->(Tag: Params) &]

[Var: 'string' = 'omni']
[$string->Reverse & Uppercase &]