They should all pass as they each evaluate to a list with one element.

Update: And they do. :-) No, not a bug. Remove the parentheses around $test and they will all fail.

-sauoq
"My two cents aren't worth a dime.";

To be more precise, each is a list assignment in a scalar (boolean) context and list assignment in a scalar context evaluates to the number of items in the list on the right-hand side of the assignment.

                - tye

Okay, but now there's a bit of a discrepancy (not a bug, I guess, but something to wonder about):

Without the parens around "$test", the first two examples produce a warning:

Found = in conditional, should be == at -e line 1.
[download]

but the third example ("= undef") does not produce any warning. (I'm running 5.8.0, in case that makes a difference.)

The warning is just trying to help you out so that you don't have an if that evaluates to a constant boolean value which these all do. Consider:

... if($val == 3);
#versus
... if($val = 3);
[download]

In the first is checks to see if $val is 3 and in the second it sets $val to be 3 and then checks $val for truth which in this case is always true. So for normal situations that line should just be:

...; $val=3;
[download]

Which would have the same effect in my little sample program.

D'oh. {blush}

---

Examine what is said, not who speaks.
"Efficiency is intelligent laziness." -David Dunham
"When I'm working on a problem, I never think about beauty. I think only how to solve the problem. But when I have finished, if the solution is not beautiful, I know it is wrong." -Richard Buckminster Fuller

Eh? I thought a LIST would evaluate to it's final element in scalar context -- so in this case, they should evaluate to 0, '', and undef respectively.

Only an ARRAY would eval to the number of elements...

Am I missing something?

Matt

Am I missing something?

Yes. See tye's reply to me in which he explains it more precisely than I did.

-sauoq
"My two cents aren't worth a dime.";

hmmm.. what am I doing wrong here? (perl, v5.8.0 built for i686-linux)

]$ perl -wMstrict -e"if( my($test) = 0 ) { print 'Passed'; } else { pr
+int 'Failed'; }"
Can't declare stub in "my" at -e line 1, near ") ="
Execution of -e aborted due to compilation errors.

]$ perl -wMstrict -e"if( my($test) = '' ) { print 'Passed'; } else { p
+rint 'Failed'; }"
Can't declare stub in "my" at -e line 1, near ") ="
Execution of -e aborted due to compilation errors.

]$ perl -wMstrict -e"if( my($test) = undef ) { print 'Passed'; } else 
+{ print 'Failed'; }"
Can't declare stub in "my" at -e line 1, near ") ="
Execution of -e aborted due to compilation errors.

]$ perl -wMstrict -e "if( my $test = undef ) { print 'Passed'; } else 
+{ print 'Failed'; }"
syntax error at -e line 1, near "my  ="
Execution of -e aborted due to compilation errors.
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I had to swap "/' to get it to run..

]$ perl -wMstrict -e 'if( my ($test) = undef ) { print "Passed"; } els
+e { print "Failed"; }'
Passed

]$ perl -wMstrict -e 'if( my $test = undef ) { print "Passed"; } else 
+{ print "Failed"; }'
Failed
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cheers,

J

Because $test is in double-quotes, your shell is trying to interpolate it. Since it isn't set though (and there aren't such things as warnings and strict for the shell ; ), it is replaced with nothing and becomes:

perl -wMstrict -e"if( my() = 0 ) { print 'Passed'; } else { print 'Fai
+led'; }"
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If you escape the $ you'll be fine.

perl -wMstrict -e"if( my(\$test) = 0 ) { print 'Passed'; } else { prin
+t 'Failed'; }"
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A better way is to make sure the shell doesnt even try...
perl -wMstrict -e'if( my() = 0 ) { print "Passed"; } else { print "Failed"; }'

T I M T O W T D I

Different command line semantics between Win32 and linux shells.

---

Examine what is said, not who speaks.
"Efficiency is intelligent laziness." -David Dunham
"When I'm working on a problem, I never think about beauty. I think only how to solve the problem. But when I have finished, if the solution is not beautiful, I know it is wrong." -Richard Buckminster Fuller