On Oct 30, 11:15 am, [EMAIL PROTECTED] (Chas. Owens) wrote: > On 10/30/07, Kaushal Shriyan <[EMAIL PROTECTED]> wrote: > snip> Whats the exact purpose of use strict > > snip > > The strict pragma has three effects (unless modified by arguments): > 1. most variables must be declared (there are some exceptions)
This is a common misperception. use strict 'vars' in fact does not require anything to be declared. All it requires is that global variables must be fully qualified. You cannot use the short-name of globals that belong to the current package. That is, without strict: #!/usr/bin/perl $foo = "hello, world\n"; print $foo; __END__ is the same as: #!/usr/bin/perl $main::foo = "hello, world\n"; print $main::foo; __END__ When Perl sees '$foo' and sees that no lexical with that name has been declared in the current scope, it assumes you are talking about the global $foo from the current package (which is in this small example, 'main'). It then pretends that you wrote $main::foo instead of $foo. With strict 'vars' enabled, Perl makes the same assumption, but this time tells you that the global variable $foo must be fully qualified (ie, written $main::foo). It won't allow the shortcut now. Regardless, you can still use global variables, and there is still no requirement to declare them: #!/usr/bin/perl use strict; $main::foo = "hello, world\n"; print $main::foo; __END__ With strict enabled, the only way to use a short-name of a variable is to declare a lexical of that name (the right choice) using 'my', or to disable strict 'vars' on a variable-by-variable case using 'our' (the wrong choice). This is what leads people to assert "use strict forces you to declare your variables". Paul Lalli -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/
