12 lines
732 B
Text
12 lines
732 B
Text
When an undefined variable is dereferenced, it gets silently upgraded to an
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array or hash reference (depending of the type of the dereferencing). This
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behaviour is called autovivification and usually does what you mean (e.g. when
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you store a value) but it may be unnatural or surprising because your variables
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gets populated behind your back. This is especially true when several levels of
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dereferencing are involved, in which case all levels are vivified up to the
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last, or when it happens in intuitively read-only constructs like exists.
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This pragma lets you disable autovivification for some constructs and optionally
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throws a warning or an error when it would have happened.
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WWW: https://metacpan.org/release/autovivification
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