Hi Alexey,
If I remember correctly, when you assign a value to an lvalue like this:
$foo ＝ 1；
The value of the assignment is the value on the right hand side of the equal
sign.
So when you do something like:
if ($foo＝2){...}
It has the same effect as this:
$foo＝2;
If (2){...}
The condition is always true, and the compiler will wonder your attempt here.
Similarly, when you write:
If ($foo＝$bar){...}
it is translated as:
$foo＝$bar;
If ($bar){...}
The condition is completely valid, and thus compiler won't complain.
Cheers,
Jing
On 15 Aug 2013, at 01:21, Alexey Mishustin <shum...@shumkar.ru> wrote:
> Hello all,
>
> If I make a typo and write a single "equals" operator here:
>
> #!/usr/bin/perl
>
> use strict;
> use warnings;
>
> my $foo = 1;
> my $bar = 2;
>
> if ($foo = 2) {
> print "yes\n";
> }
> else {
> print "no\n";
> }
>
> ...then the "warnings" pragma works OK and tells me "Found = in
> conditional, should be ==..."
>
> But if I make the same typo and write a single "equals" operator there:
>
> #!/usr/bin/perl
>
> use strict;
> use warnings;
>
> my $foo = 1;
> my $bar = 2;
>
> if ($foo = $bar) {
> print "yes\n";
> }
> else {
> print "no\n";
> }
>
> ... then I get no warning; the script output is "yes".
>
> Why is it so?
>
> How could I catch such typos?
>
> --
> Regards,
> Alex
>
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