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Re: The Assignment Principle

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From	Eric Sosman <esosman@comcast-dot-net.invalid>
Newsgroups	comp.lang.java.programmer
Subject	Re: The Assignment Principle
Date	Sun, 26 Jan 2014 15:39:16 -0500
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On 1/26/2014 3:17 PM, Stefan Ram wrote:
>    I once read the »Assignment Principle«. It says that after
>    an assignment a comparison with the assigned value yields
>    true. Assuming v was declared properly:
>
> v = 2;
> java.lang.System.out.println( v == 2 ); // prints true
>
>    I think we can assume a single thread of execution and
>    normal memory [not I/O registers or so]. Also, it is
>    about values and not expressions, so that
>
> v = java.lang.Math.random();
> java.lang.System.out.println( v == java.lang.Math.random() );
>
>    is not a counterexample.
>
>    Being cautious, I'd like to ask: Do you see any exceptions,
>    where this does not hold? (I suggest to reply only if the
>    answer to that question is »yes«.)

	double x = Double.NaN;
	assert x == NaN;  // ka-BOOM!

-- 
Eric Sosman
esosman@comcast-dot-net.invalid

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Re: The Assignment Principle Eric Sosman <esosman@comcast-dot-net.invalid> - 2014-01-26 15:39 -0500

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