The data Operator

Any text not matching &Attribute-Name or module-code is interpreted as a value for a particular data type.

Double-quoted strings and back-quoted strings are dynamically expanded before the condition is evaluated. Single-quoted strings are static literals and are not dynamically expanded.

When used as an existence check, the condition evaluates to true if the data is non-zero. Otherwise, the condition evaluates to false.

For integer existence checks, 0 is false; all other values are true.

For string existence checks, an empty string is false. All other strings are true.

All other data types are disallowed in existence checks.

Examples:

"hello there"
5