оценивать аргументы как выражение (evaluate arguments as an expression)
Операнды (Operands)
The single expression evaluated by expr shall be formed from the
operand operands, as described in the EXTENDED DESCRIPTION
section. The application shall ensure that each of the expression
operator symbols:
( ) | & = > >= < <= != + - * / % :
and the symbols integer and string in the table are provided as
separate arguments to expr.
