Re: Why no $@ after eval? Bug?

[Chady]

in reply to Why no $@ after eval? Bug?

They do not produce different results. Look:

$ perl -e 'eval { map { $_++ } 1 };'
$ perl -e 'eval { map { $_++ } 1 }; print $@;'
Modification of a read-only value attempted at -e line 1.
$ perl -e '       map { $_++ } 1 '
Modification of a read-only value attempted at -e line 1.

In the first attempt, you have your code in an eval block, so the error is stored in $@.

Now, why isn't it getting printed?
I'm assuming it's because rmap evaluates the code it is being handed my @got = eval { $self->call(); }; so it is overwriting the value of $@ and thus when your eval block gets out it doesn't print the error message. I would assume that calling evals inside of eval could get messy.

Someone cares to elaborate about eval inside of eval? for example, why doesn't this:

$ perl -e '$n = q/eval { die;}; print "1: $@"/; eval {$n}; print "2: $
+@"'

print out "1: Died at (eval 1) line 1." ?

[hv]

Someone cares to elaborate about eval inside of eval? for example, why doesn't this:

$ perl -e '$n = q/eval { die;}; print "1: $@"/; eval {$n}; print "2: $
+@"'

print out "1: Died at (eval 1) line 1." ?

Mainly because you left out "-w", which would have helped point you to the fact that you used eval {$n} instead of eval $n. Making that change gives you the output you'd expect.

Hugo