Musing on Mark Jason Dominus's Seven Useful Uses of local, I think I've come up with another one.
The most common use I have for local is with %ENV. The article doesn't specifically mention environment variables. There are instances where I am doing one of the following:
Forking several times with %ENV{FOO} set to different values, and I need to keep its original or unset value in the parent. Writing tests for something that reads an environment variable (see Module::Optional for an example) Opening Tk top level windows on multiple displays (see Re: Tk - is MainWindow robust?)
Thinking about it more, I would suggest that @ARGV belongs in the same category, as used in the file slurp idiom: my $slurp = do { local (@ARGV, $/) = 'foo.txt'; <>};
There's also localising @ARGV for handling INCLUDE directives in the input stream.
These uses of local could be thought of as a special case of number 6 (Dynamic Scope Revisited), or possibly number 1 (Special Variables), but I think they are a new category.
Update:Looks like there might be a problem with plover.com - try this link as an alernative for MJD's article.
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