Learning Perl on Win32 Systems

Chapter 9. Miscellaneous Control Structures

The last Statement

In some of the previous exercises, you may have thought, “if I just had a C break statement here, I’d be done.” Even if you didn’t think that, let me tell you about Perl’s equivalent for getting out of a loop early: the last statement.

The last statement breaks out of the innermost enclosing loop block,^[61] causing execution to continue with the statement immediately following the block. For example:

            while (something) {
		something;
		something;
		something;
		if (somecondition) {
			somethingorother;
			somethingorother;
			last; # break out of the while loop
		}
		morethings;
		morethings;
}
# last comes here

If somecondition is true, the somethingorothers are executed, and then the last forces the while loop to terminate.

The last statement counts only looping blocks, not other blocks that are needed to make up some syntactic construct. As a result, the blocks for the if and else statement, as well as the one for a do {} while/until, do not count; only the blocks that make up the for, foreach, while, until, and “naked” blocks count. (A naked block is a block that is not otherwise part of a larger construct, such as a loop, subroutine, or if/then/else statement.)

Suppose we wanted to see whether a mail message that had been saved in a file was from Erik. Such a message might look like:

From: [e-mail] (Erik Olson) To: [e-mail] Date: 01-MAY-97 08:16:24 PM MDT -0700 Subject: A sample mail message Here's the body of the mail message. ...