Question

I have a statement

$set eq "Y" ? $set = "N" : $set = "Y";

But no matter what it always sets to "N"

# Toggle setting
if ($set eq "Y")
{
   $set = "N";
}
else
{
   $set = "Y";
}

Why doesn’t the one liner seem to work?

Answer 1

Due to precedence rules, perl is not parsing your statement as you think:

$ perl -MO=Deparse,-p -e '$set eq "Y" ? $set = "N" : $set = "Y"'
((($set eq 'Y') ? ($set = 'N') : $set) = 'Y');
-e syntax OK

So as you see, in both conditions, the final result is the $set scalar which then gets set to Y.

You can fix it with a few parens:

$set eq "Y" ? $set = "N" : ($set = "Y")

But why repeat the assignment:

$set = $set eq 'Y' ? 'N' : 'Y';