Re: Perl if statements evaluates wrongly if we use '=>' as operator

praveen.kane@xxxxxxxxx <praveen.kane@xxxxxxxxx> wrote:

Perl if statements evaluates wrongly if we use '=>' as operator


No it doesn't.


Steps to reproduce :
---------------------------
1. Try to compare the scalar value using '=>' operator (comma
operator)


That is not possible, as the comma operator does not do comparisons...


Below is the Perl code where issue will able to reproduce.

___________________________________________
#!/usr/bin/perl

$count = 10;
print "Count value : 10 \n";

if ($count => 20) {


The comma operator evaluates its left operand and discards
the result, then evaluates its right operand.

So you have the equivalent of

if (20) {

there, which is clearly true.

So, Perl is not doing anything "wrongly" here...


print "Count value is greater than 20 \n ";


.... you are doing something wrongly here, as you have not
tested to see if $count is >= 20 anywhere.


}else {
print "Count value is less than 20 \n";
}

___________________________________________


OutPut :
___________________________________________
[root@osdc-pxe001 pramuSUITE]# perl new1.pl
Count value : 10
Count value is greater than 20
[root@osdc-pxe001 pramuSUITE]#

___________________________________________


Observation:
-------------------
1. Perl expression using '=>' operator is returning true/


As it should.


1 ,irrespective of condition .


As it should.


2. Successfully complete execution and executes if block irrespective
of condition.


As is should.


we expect :
-----------------
Perl should throw proper compilation error


Why?

You have valid syntax.

Your error is in semantics, not in syntax.

If you want to do a comparison, you should use a comparison operator.


--
Tad McClellan
email: perl -le "print scalar reverse qq/moc.liamg\100cm.j.dat/"
The above message is a Usenet post.
I don't recall having given anyone permission to use it on a Web site.
.

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