CODEWITHSUNDEEP
perl
user3435709
user3435709

Reputation: 23

Looping through variables to check if defined

I am attempting to check a bunch of variables to ensure that they are defined. I thought I would put the variable names in an array and loop over the array checking if each variable was defined. However, as best I can understand it, the use of symbolic references for lexical variables (defined by "my") does not work.

Is there a way in Perl to check if a large number of lexical variables are defined without resorting to putting each variable name into a defined statement manually? It would seem to be better if I could create an array or something to hold the names of the variables whose defined status I wish to check.

Upvotes: 2

Views: 124

Answers (2)

LeoNerd
LeoNerd

Reputation: 8532

It sounds like you need to rethink the structure of your code. Having a large number of lexical variables like that suggests a bad design - should they perhaps not live in a hash or an array? Then they could be iterated over much simpler.

Upvotes: 0

ikegami
ikegami

Reputation: 385657

Also put a ref to the var in the array.

my @vars = (
   [ '$x', \$x ],
   [ '$y', \$y ],
   [ '$z', \$z ],
);

for (@vars) {
   my ($name, $ref) = @$_;
   print("$name is undefined\n") if !defined($$ref);
}

I don't see what's so hard about including a name when you include the variable. The alternative is to have PadWalker scan the internals. I wouldn't use that in production, but it can be useful in a debugging tool.

Upvotes: 2

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