Perl: You don't want to miss! -2-

This post will be about loops and conditions! Hopefully this will be too short.

Loops and if conditions are not much differnt from other langauges:

while, for, do-while, if, foreach

What seems new to me (Cx & Java developer)

- if -elseif

- until (negative of "while": while not)

- do ... until

- unless (negative of "if": if not)

What about loop controls?

- last (aka "break")

- next (aka "continue")

- redo (the amazing keyword, just redo the loop!)

while(<STDIN>) #Keep reading the standard input

{

print; #No argument? yes, it defaults to printing the magic variable: $_

if($_ > 0) {

$_--; #Decerement

redo; #Back to the top of the loop without executing the condition body!

}

}

Expression Modifier

What about rephrasing the "redo"?

redo if $_-- > 0; #Remember, the post-decrement has the lower precedence

See, the statement (action) comes before the condition in this expression modifier.

This is valid for the "if" and "unless" too. Give it a try!