2.3.15 With

A WITH statement has the form:

    WITH id = e DO S END

where id is an identifier, e an expression, and S a statement. The statement declares id with scope S as an alias for the variable e or as a readonly name for the value e. The expression e is evaluated once, at entry to the WITH statement.

The statement is like the procedure call P(e), where P is declared as:

    PROCEDURE P(mode id: type of e) = BEGIN S END P;

If e is a writable designator, mode is VAR; otherwise, mode is READONLY. The only difference between the WITH statement and the call P(e) is that free variables, RETURNs, and EXITs that occur in the WITH statement are interpreted in the context of the WITH statement, not in the context of P (see the section on designators).

A single WITH can contain multiple bindings, which are evaluated sequentially. That is:

    WITH id_1 = e_1, id_2 = e_2, ...

is equivalent to:

    WITH id_1 = e_1 DO
      WITH id_2 = e_2 DO ...