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From: Lawrence D'Oliveiro <ldo@nz.invalid>
Newsgroups: comp.lang.c
Subject: Shortcut Booleans
Date: Fri, 7 Jun 2024 10:52:51 -0000 (UTC)
Organization: A noiseless patient Spider
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I wonder why, traditionally, shortcut evaluation of boolean subexpressions 
has been applied to “and” and “or” connectives, but not any others.

For example, what about “implies”?

    a implies b

Truth table:

    a  b  result
    ------------
    0  0    1
    0  1    1
    1  0    0
    1  1    1    

But C does not have an “implies” operator, I hear you say? Of course this 
can be written

    not a or b

and shortcut evaluation would apply. But it can also be written

    a <= b

and shortcut evaluation would *not* apply. Why not, if a and b are 
boolean-valued subexpressions?