Derivation of PL/I

In article <38aafe7a\$0\$26824@news.sanjose1.level3.net>,
Randall Hyde <rhyde@shoe-size.com> wrote:
>Tim Goodwin <tjg@star.le.ac.uk> wrote in message
>news:888opg\$uem\$1@ltpcg.star.le.ac.uk...
>> I think if you replace "binary" with "arithmetic", you'll find that the
>> rule is consistent.  It doesn't extend to logical operators.
>
>Why is   A &= B; allowed but A &&= B; is not allowed?

Like I said, assignment expresssions are consistent for arithmetic
operators, but don't extend to logical operators.  `&&' is a logical
operator (that is, it deals with things that are of Boolean type).

>Repeat complaint for >> and <<.

`>>' is an arithmetic operator, so the corresponding assignment
operator exists.

`>' is a logical operator, so there is no corresponding assignment
operator.

Tim.
--
Tim Goodwin   | "If you don't know what closures are, you probably don't
Leicester, UK | want to know what closures are." -- Larry Wall