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) 2. only real references are allowed (symbolic references are considered an error) 3. barewords are considered to be subroutines and error if there is no definition Unless you are writing a command line invocation, you want these strictures. Here is an example of how it will save you time and effort: 1. variables my $foo = 5; $fo++; print "$foo\n"; Without strict this code runs and prints five even though the expected value was six. In this example we can easily find the error, but in a large program it is much harder. The strict pragma tells us that $fo on line 2 was not declared. 2. references Back in the dawn of time it was thought that it was a good idea to allow you to say $foo = 5; $bar = "foo"; print $$bar, "\n"; Later it was realized that this is not a good idea and we got real references my $foo = 5; my $bar = \$foo; print $$bar, "\n"; The strict pragma prevents your code from doing something weird if you try to dereference a string and forces you to use the better way of handling references. 3. barewords Also back in the dawn of time, it was thought to be a good idea to let barewords (a sequence of \w characters that Perl does not recognize) be treated as strings: print STDOUT foo, bar, baz, "\n"; Over time it was realized that barewords as strings was not a good idea (they are confusing and can cause issues with subroutine name resolution). All of these strictures cause problems for old code, so they are not made mandatory, but in truth, every modern Perl program should start with the strict pragma. -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/
