Re: [BLACKBOX] Program freezes when window loses focus

From: [at]} <Rex>
Date: Tue, 29 Mar 2011 17:33:40 -0500

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At 04:35 PM 3/29/2011, you wrote:
>The principles behind ReadKey are in complete opposition to the principles
>that Oberon (& BB) operate on. Oberon and BB operate on an event-driven
>model in which the code that we write is expected to provide handlers that
>the event loop calls in response to an event. In this sense they are always
>'waiting for' a keystroke or similar event. In other words, it's
>asynchronous, like an interrupt handler. You should not be writing code to
>read directly from the keyboard.


        I see. That's fine. I don't really care how one gets the keystroke, but there must be a simple way of reading keys. BB reads keystrokes SOMEHOW (I don't know, maybe it's complicated). Is there a SIMPLE way of handling the following three cases, for example?

1. REPEAT
        (* I don't know how long this loop will take. If it takes a month, I might want to
                interrupt it *)
UNTIL something happens (* message from windows that a key is pressed? *)

2. I'm doing a delicate visual, graphical manipulation and I want to nudge an image around with keystrokes.

3. Suppose you want to write a specialized editor. You need to read a keystroke and (optionally) display it. How does the BB environment read a keystroke?

        Any hints?

Rex Couture

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Received on Wed Mar 30 2011 - 00:33:40 UTC