Re: [BLACKBOX] Read-only IN parameters for all data types

From: [at]} <Rex>
Date: Tue, 19 Feb 2008 15:31:06 -0600

----boundary-LibPST-iamunique-1106863655_-_-
Content-type: text/plain

Chris,
        Thanks for figuring this out. You're ahead of most of us on this one.

        As much as I hate to see any fork, I like the suggested modifications. Unless you remove passing by value from the interface, the changes would rarely break any existing code. Future code written to the suggested specifications would not be backward-compatible, but the differences would be easy to understand and easy to fix at compile time.

        The one exception is that the changes might break existing code in case of mixed-language programming. That is always so implementation-specific anyway that I don't see a problem, as long as the exact behavior of the compiler is carefully documented, and clearly tagged as a variation from the spec.

        I was going to suggest just removing the keyword "IN", but you reminded us why it's useful to declare the intention before all parameters. As long as you're forking anyway, you might as well just require the use of "IN", "OUT", or "VAR".

        While you are at it, if you are still serious about porting the compiler, there's one other language detail you might consider fixing. Because of the way the FOR statement is defined,
FOR i:= 1 to MAX (INTEGER) DO;
is an infinite loop. The Pascal specification avoids this problem, and I can't imagine that it entails a substantial computational cost. I don't have my copy of Jensen and Wirth here, but e-mail me if you need a copy.

Sincerely,
Rex Couture

----
To unsubscribe, send a message with body "SIGNOFF BLACKBOX" to LISTSERV{([at]})nowhere.xy----boundary-LibPST-iamunique-1106863655_-_-
Content-type: application/rtf
Content-transfer-encoding: base64
Content-Disposition: attachment; filename="rtf-body.rtf"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----boundary-LibPST-iamunique-1106863655_-_---

Received on Tue Feb 19 2008 - 22:31:06 UTC