Thanks to all,
2013/8/14 Jim Gibson <jimsgib...@gmail.com>:
> The problem is that the construct
>
> if( $foo = $bar ) {
> ...
>
> is not always a typo. It means: "assign value of $bar to variable $foo and
> test if the result is logically true", which is perfectly valid. If that were
> not allowed, then you would have to write:
>
> $foo = $bar;
> if( $foo ) {
> ...
>
> which not everyone would like.
2013/8/14 Rob Dixon <rob.di...@gmx.com>:
> The `warnings` pragma catches the first form because the value of the
> conditional is a *constant* 2, so the body of the `if` will *always* be
> executed and it is a fair guess that the problem is `=` instaed of `==`.
>
> In the second case the execution depends on the value of `$bar`, and it
> is a reasonable thing to write if, say, you wanted to test a value and
> assign it to a temporary variable at the same time. Perl cannot know
> that the code was unintentional and will not warn you.
Testing a value and assigning it - I have never done this at the same time...
> I have checked both Perl::Critic and B::Lint, and neither of these check
> for an assignment operator in a conditional expression. The only thing
> way I can think of doing this is to write a plugin for B::Lint, which
> accepts Module::Pluggable plugins. It may be possible to write something
> that will do what you want.
Thanks for the suggestion. I'll give a look at B::Lint.
2013/8/14 Jing Yu <logus...@googlemail.com>:
> Or maybe he can write a perl script to check the "if/while" conditionals of
> his perl script...
>
> while(<>){
> say '= is detected where == is expected at line ',"$." if
> /if\s*\(\S+?=[^=]/;
> }
Yes, if I meet difficulties with B::Lint, I'll have nothing to do but
to parse my code... Today I passed more than an hour debugging this
kind of "not always a typo" in a project of few thousands lines. xD.
So, I would not like this to be repeated.
--
Best regards,
Alex
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