The "used only once" warning isn't there to spot declared, but unused variables. They are harmless. The "used only once" warning is there to catch typos in variables - "use strict" won't catch typos in fully qualified variable names - which certainly can be harmfull.

Personally I think this warning is one of the more annoying ones. It triggers to many false positives (at least, for the way I code). I hate having to use local, our, or use vars just to quiet the warning.

I'm not sure what you mean by "using a string as a number". Scalars in Perl are both strings and numbers. But Perl does already warn you (if you have warning on) if you use a string that doesn't look like a number as an operand for an arithmetic operation. 

    $ perl -we '"foo" + "bar"'
    Argument "bar" isn't numeric in addition (+) at -e line 1.
    Argument "foo" isn't numeric in addition (+) at -e line 1.

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Abigail

In reply to Re: Using "my" suppresses "Name used only once" warning? by Abigail-II
in thread Using "my" suppresses "Name used only once" warning? by Wysardry

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