So what does eval actually do, and actually trap?

Considering this code:

    eval { $content = $self->web_fetch( { raw => 1 } ); }; # a
    $content = eval { $self->web_fetch( { raw => 1 } ); }; # b
    if ($EVAL_ERROR) { # $@
      return $self->do_harvest_return(undef);
    }

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(We can assume that web_fetch and do_harvest_return are methods written by us, and contain some carp and croak statements)

#1 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 (unlike, for example, print - which returns true on a successfull print)

I assume $EVAL_ERROR will contain the first croak (or other fatal) error from the web_fetch method in both a and b

.... but what about the difference between a and b - doesn't a also report if the assignment to $content fails? - if so, why does best practice suggest b? (2nd Edition, P 277)

#2 Is there a preferred style for using eval?



-- Ian Stuart
A man depriving some poor village, somewhere, of a first-class idiot.

In reply to What does eval actually do? by kiz

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