in reply to the try/catch example from "Programming Perl" analyzed
On a tangently related point, I'm rather unsatisfied with the idioms for OO exception handling in Perl.
With Java exceptions, you are guarenteed that any caught exception is an object (one place where Java's nearly-pure OO environment comes in handy). In Perl, you also have to handle the condition of a runtime error which is not an object:
eval { do_something_that_could_die() }; if($@) { # We know it died, but is it an object or a # printable message? if( ref $@ ) { # Assume it's an exception object. Not a # great way to do it, but it works. # # Now, what kind of exception is it? # if( $@->isa( 'IOException' ) ) { . . . } elsif( $@->isa( 'OtherException' ) ) { . . . } else { . . . } } else { # Assume it's an error string . . . } }
If you're good aboug indenting your code, then this produces an extra level of indentation (and an extra case) that Java doesn't have. Java does have an extra level by nature of enclosing everything in a class declaration, but this is compensated by using 4-space indent, whereas most Perl code can reasonably sit in an 8-space indent. (Of course, I'm now sitting dangerously close to a coding-style flame war.)
Thank God for folding editors, or this would be a huge blight to see in the middle of a subroutine.
"There is no shame in being self-taught, only in not trying to learn in the first place." -- Atrus, Myst: The Book of D'ni.
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