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+?=[^=]/;
}
On 15 Aug 2013, at 03:02, Rob Dixon <rob.di...@gmx.com> wrote:
> On 14/08/2013 18:21, Alexey Mishustin wrote:
>>
>> If I make a typo and write a single "equals" operator here:
>>
>> if ($foo = 2) {
>> print "yes\n";
>> }
>>
>> ...then the "warnings" pragma works OK and tells me "Found = in
>> conditional, should be ==..."
>>
>> But if I make the same typo and write a single "equals" operator there:
>>
>> if ($foo = $bar) {
>> print "yes\n";
>> }
>>
>> ... then I get no warning; the script output is "yes".
>>
>> Why is it so?
>>
>> How could I catch such typos?
>
> The `warnings` pragma catches the first form because the value of the
> conditional is a *constant* 2, so the body of the `if` will *always* be
> executed and it is a fair guess that the problem is `=` instaed of `==`.
>
> In the second case the execution depends on the value of `$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.
>
> 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.
>
> Rob
>
>
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