There's an implicit statement that eval does not return true or false on it's own... the implication is that it doesn't return anything

Have you read all of the documentation?

In both forms, the value returned is the value of the last expression evaluated inside the mini-program ... If there is a syntax error or runtime error, or a die statement is executed, eval returns undef in scalar context or an empty list in list context, and $@ is set to the error message.

Also, there are several issues with $@ (some have been addressed in recent versions of Perl), for example the Try::Tiny documentation section "Background" contains a good description. Unfortunately, there are lots of examples on the net that still use the problematic form eval { ... }; if ($@) ...

That's the background of Corion's suggestion of having the eval block return a true value on success and checking that using my $ok = eval { ...; 1 }; if (!$ok) ... (which could also be written as eval { ...; 1 } or die ... for example), or Try::Tiny. Those are also my preferred style.

In reply to Re: What does eval actually do? by Anonymous Monk
in thread What does eval actually do? by kiz

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