in reply to Re^4: 'xor' operator is not a sibling to 'or' and 'and'?
in thread 'xor' operator is not a sibling to 'or' and 'and'?

It's further down under the heading "Logical Defined-Or" (so yes, it's disjoint from the other discussion of && above it): 

    The "||", "//" and "&&" operators return the last value evaluated 
+(unlike
    C's "||" and "&&", which return 0 or 1). Thus, a reasonably portab
+le way
    to find out the home directory might be:

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The cake is a lie.
The cake is a lie.
The cake is a lie.

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Re^6: 'xor' operator is not a sibling to 'or' and 'and'?
by rsFalse (Chaplain) on Dec 18, 2019 at 21:35 UTC
    Hm, paragraphs about '||,//,&&' and about 'and/or/xor' are distant in docs, because their precedence differs. But also sentences about return values of 'and' and 'or' seems to be incorrect. I think that section needs to be slightly rewritten, with emphasis that 'and' and 'or' do not return logical result, but return evaluated expressions.
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      Stop thinking in terms of bitwise; this is Boolean. The "evaluated expressions" are logical values. 2 is logic-true, 3 is logic-true, 2 and 3 returns 3, which is logic-true. It uses the last evaluated expression as the logical value.

      C:\usr\local\share\PassThru\perl>perl -le "print +('george' and 'graci
+e')"
gracie

C:\usr\local\share\PassThru\perl>perl -le "print +('0' and 'gracie')"
0

C:\usr\local\share\PassThru\perl>perl -le "print +('' and 'gracie')"


C:\usr\local\share\PassThru\perl>perl -le "print +('george' and 'false
+')"
false

C:\usr\local\share\PassThru\perl>perl -le "print +('george' and '')"


C:\usr\local\share\PassThru\perl>perl -le "print +(2 and 4)"
4

C:\usr\local\share\PassThru\perl>perl -le "print +(2 && 4)"
4

C:\usr\local\share\PassThru\perl>perl -le "print +(2 & 4)"
0

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        >> Stop thinking in terms of bitwise; this is Boolean.

        If this is Boolean, shouldn't it return 1 or ''/0?
        p.s. I haven't write anything about bitwise.
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      > I think that section needs to be slightly rewritten

      I agree that && and || should be extended with the notion: "returns last evaluated side".

      Probably with an analogous if statement.

      A || B := do { if (A) {A} else {B} }

      I disagree that they "do not return logical result" , because the truth table is fully respected.

      I don't think the docs to and/or need to be extend, because their low precedence and use for flow control makes the use of return values unlikely without brackets. Mentioning the similarity to && and || should be sufficient.

      Cheers Rolf
      (addicted to the Perl Programming Language :)
      Wikisyntax for the Monastery FootballPerl is like chess, only without the dice

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